African Elephant Loxodonta africana - Life Stages (Literature Reports)

Living Organisms / Animalia / Craniata / Mammalia / Proboscidea / Elephantidae / Loxodonta / Species:

< > LIFE STAGES with literature reports for the African Elephant - Loxodonta africana: Use sub-contents list below, or simply scroll down the page to view findings.

Breeding Season
Oestrus / Ovulation
Mating / Gestation / Pregnancy
Parturition / Birth
Neonatal Development
Litter Size
Time between Litters/ Litters per year
Lactation / Milk Production
Sexual Maturity
Male Seasonal Variation
Longevity / Mortality
- Age Estimation Techniques
Authors & Referees

LIFE STAGES - Editorial Comment

Editorial Comment

(Editorial Overview Text Replicated on Overall Species page - Loxodonta africana - African Elephant)

BREEDING SEASON: Mating may occur in all months, but even on the equator there are breeding peaks, generally during the rainy season. Such peaks may be associated with better nutrition and protein intake with the growth of new grass promoted by the rains.

OESTRUS/OVULATION/FERTILITY: Female African elephants are polyoestrous and monovular (produce a single egg at any one oestrus). There are several sterile oestrus cycles prior to ovulation and conception. Oestrus lasts two to six days, possibly up to ten days. It is generally stated that the oestrus cycle is about three weeks long with a series of cycles lasting for about two months; a cycle of about 16 days has been recorded in captive elephants while a study of elephants in Amboseli found that if a female failed to conceive the next heat occurred about three months later. Recent studies on hormone levels have shown that the cycle is about 14 to 16 weeks long, with two LH peaks, three weeks apart, the second of which is followed by ovulation. Following calving, there may be a lactational anoestrus, (i.e. the female does not come into oestrus while she is lactating); this may last until the calf is about two years old. Females may be most fertile from about 25 years old and show declining fertility after about 40 or 45 years old, although even cows over fifty may produce calves. Conception rates may be reduced with poor nutrition, as seen in drought conditions.

GESTATION/PREGNANCY: Gestation generally lasts about 22 months; from zoo data a gestation length averaging 660 days has been determined while the average in one wild population (Amboseli) was 656 days.

PARTURITION/BIRTH: The cow may or may nor separate from her group before giving birth. Other females often gather around the calving cow. The cow is restless before the birth and may scrape the ground (the effect is to remove twigs and pebbles from the area where she is standing, although opinions differ as to whether this is deliberate). Usually, the birth itself is quick, although a labour of four hours has been observed in the wild. In a watched birth of twins in the wild, the calves were born twenty minutes apart. The umbilical cord ruptures as the calf drops to the floor. The fetal membranes are removed by the mother and/or other females, not always gently, and the mother (and sometimes other females) encourages and assists the calf to stand, using feet, trunk and tusks.

Seasonality: Births may occur all year but there is generally a peak in births just before the peak of the rains. This timing allows good lactation (due to the growing grass) as well as providing cover and cool conditions for the very young calf.

NEONATAL/DEVELOPMENT:

Elephant calves are precocial; they attempt to stand almost immediately and may stand after a period of a few minutes to an hour or more (about thirty minutes may be average). Once on their feet they search for the nipples and suckle using their mouth (NOT the trunk).
The ears are tight against the head at birth.
Male calves generally grow faster than do female calves; from 0.85 m at birth the calf may reach 1.1 - 1.5 m by one year old. Hand-reared calves grow more slowly than do mother-reared calves, but calves in captivity may grow faster after weaning than do wild calves, due to better nutrition and reduced parasitism.
The first cheek tooth cuts the gum when the calf is about six weeks old and is lost at one to two years.
Calves suckle frequently, every hour or less, for about 1.5 minutes at a time. Suckling becomes less frequent when the calf is about six months old. They continue suckling to at least two years old, and rarely survive if they lose their mother before this age. Calves may still suckle at three and a half or four years or even older.
Calves start to play with vegetation very early, and may investigate and sample food from their mother's mouth, but only start to actually swallow some grass at about four months. They are eating a significant amount of vegetation by six months and by two years they spend as much of their time eating as the adults do. They can manipulate sizeable branches by about six to ten years of age.
Calves first start to drink water with their trunks from about three months old.
Calves may initially have poor trunk control and may be shaky on their legs for the first few days, but can move with the herd usually from about two days old. Calves remain very close to their mother for about the first six months, then begin to move further away, to explore and to play with other calves. Young calves play vigorously with bouts lasting 30 to 50 seconds; older juveniles play less. Play includes chases, rolling over each other, mock fights, gambolling and mounting one another.

LITTER SIZE: There is usually one calf but about 1% of pregnancies may produce twins.

TIME BETWEEN LITTERS / LITTERS PER YEAR: The minimum possible calving interval is about two years, however there may be a lactational anoestrus, (i.e. the female does not come into oestrus while she is lactating) while the calf is suckling, increasing the inter-birth period to three or four years (less if the calf dies and suckling stops) . Longer inter-calf intervals may occur in conditions of poor nutrition or overcrowding, giving inter-calf intervals of sever years or longer.

LACTATION / MILK PRODUCTION: Calves are generally basically weaned by about two years old; lactation may continue during the next pregnancy but ceases before parturition with the mammary glands then developing visibly again about seven weeks before calving. Elephant milk is considered to be moderate in its contents of dry matter, fat, protein and carbohydrate.

SEXUAL MATURITY: In optimum conditions, elephants may become sexually mature at about 10 or 11 years old. Both nutritional and social factors may affect sexual maturity, so that puberty may be delayed to about 16 - 18 years of age in drought conditions or in an overcrowded population. Males, although they may be producing sperm at as young as 10 - 13 years, are unlikely to be able to compete successfully with other males and actually mate a female under about 20 years of age.

MALE SEASONAL VARIATION: There does not appear to be any male reproductive seasonality in term of spermatogenesis. [For a discussion of musth see African Elephant Loxodonta africana - Sexual Behaviour (Literature Reports)]

LONGEVITY / MORTALITY: Wild elephants may reach about 60 years of age; in captivity this might be extended to as long as 80 years. Recent data from one study suggested that calf survival to one year may be as high as 95%, although other studies have reported mortality rates as high as 10% or even 36%. Twins are rarely raised successfully. Survival may be higher for calves which have "allomothers" or "aunties". After weaning, the mortality rate may be about 5.1 - 6.6% per year to about 50 years. Mortality then rises sharply as the last molar is used up, with deaths generally occurring during the dry season since dry food cannot be effectively sheared by the remaining, smooth, grinding surface. In drought years mortality is increased; the effect on animals of different age classes may vary; bull calves, with higher growth rates and nutritional needs, are more likely to die during drought than are female calves. Deaths during drought are often from starvation rather than dehydration, with elephants, reluctant to leave a known water source, running out of vegetation in the local area. The greatest vulnerability to predation by lions, hyenas and hunting dogs is just after birth, and also when the calf starts to stray further from its mother at about six months old. As well as natural predation, elephants may die from hunting, poisoning due to eating toxic plants, disease, accidents, starvation, drowning, heat stress, and congenital malformation; snake bite is another possible cause of death.

(References are available in detailed literature reports below)

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Breeding Season

Source Information

SUMMARY: Mating may occur in all months, but even on the equator there are breeding peaks, generally during the rainy season. Such peaks may be associated with better nutrition and protein intake with the growth of new grass promoted by the rains.

Breeding may be initiated by the change in diet from low protein dry grass and browse in the dry season to high protein fresh green grass in the wet season. (B147)
A study of populations in East Africa, based on an assumed gestation length of 660 days and birth weight of 120 kg, estimated that for Murchison Fall National Park, Uganda, all calves were conceived between October and May and for the South bank all were conceived between January to October one year and March to September the following year. For elephants from Tsavo National Park, Kenya, for the period November 1964 to July 1966, conceptions occurred during the periods November to January and May to July only. It was noted that the method used probably gave a greater spread than the true dates, due to individual variations in fetal growth rate and gestation time. (P17.21.w1)
- It was suggested that the data available for the Murchison Falls populations indicated a gradual increase in fertility over the breeding season, and that the increased fertility was correlated with rainfall patterns, fertility increasing during the rains (with the February to May rains for the North bank and with the July to October rains for the South bank population). (P17.21.w1)
While mating can occur in all months, especially near the Equator, there are clear peaks even in these regions. (B451.4.w4)
- In several studies peak conceptions occur at the time of the greatest rainfall, and birth occur as the rains are increasing. Where there are two rainy seasons, the biggest peak of conceptions occurs during the first, longer rainy season, but there may be a second peak in the second rainy season. (B451.4.w4)
Mating peaks two or three months after the birth peak (which occurs just before the peak of the rains). (B387.w4)
Females generally enter oestrus during the rains. (B285.w3)
- After drought, when the rains come and food is more available, one to two months is required to improve body fat to a level where ovulation can occur. (B285.w3)

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Oestrus / Ovulation / Fertility

Source Information

SUMMARY: Female African elephants are polyoestrous and monovular (produce a single egg at any one oestrus). There are several sterile oestrus cycles prior to ovulation and conception. Oestrus lasts two to six days, possibly up to ten days. It is generally stated that the oestrus cycle is about three weeks long with a series of cycles lasting for about two months; a cycle of about 16 days has been recorded in captive elephants while a study of elephants in Amboseli found that if a female failed to conceive the next heat occurred about three months later. Recent studies of hormone levels and using ultrasound monitoring of the reproductive tract have shown that the cycle is about 14 to 16 weeks long, with two LH peaks, three weeks apart, the second of which is followed by ovulation. Following calving, there may be a lactational anoestrus, (i.e. the female does not come into oestrus while she is lactating); this may last until the calf is about two years old. Females may be most fertile from about 25 years old and show declining fertility after about 40 or 45 years old, although even cows over fifty may produce calves. Conception rates may be reduced with poor nutrition, as seen in drought conditions.

Female African elephants are polyoestrous. (B147)
The oestrus cycle is about two months long. (B147)
Based on data from hormone profiles in several cows, it has been shown that the oestrus cycle has a duration of about 14 to 16 weeks. (B396.3.w3)
- The main progestins secreted by the corpus luteum of African elephants have been shown to be 5α-prenane-3,20-dione (5α-DHP) and 3α-hydroxy-5α-pregnan-20-one (5α-P-3α-OH). (B396.3.w3)
- It appears that there are perhaps five waves of follicular growth, about three weeks apart, with the obvious progestin cycle of 14-16 weeks representing the culmination of one of these ovulation waves, and formation of a functional corpus luteum. (B396.3.w3)
- There appear to be two LH surges within the 14-16 week cycle, about three weeks apart and with the second peak being associated with increased progestin levels. (B396.3.w3)
- Elevated FSH levels at the start of the non-luteal phase initiate two waves of follicular development, each with a distinct LH peak; which the follicles of the first wave never ovulate but regress and form corpora lutea (these secreting hormones later in the cycle), the second wave of follicular development results in one large follicle which ovulates after the second surge in LH. Following ovulation, progestin levels rise as the CL matures while FSH rises gradually to peak at the end of the luteal phase. (B396.3.w3)
The oestrus cycle of elephants in 13 - 17 weeks long, including a luteal phase of 8 - 10 weeks and a follicular phase of 4 - 7 weeks. (J23.40.w1)
Analysis of progesterone and luteinizing hormone concentrations in serum of four female African elephants found the ovarian cycle to average 15.9 +/- 0.6 weeks (based on data for 25 cycles), with the active luteal phase lasting 10.0 +/- 0.3 weeks (range 8 - 14 weeks) and the interluteal phase 5.9 +/- 0.6 weeks. Average progesterone concentrations during the luteal phase were 328 +/- 13 pg/mL. (J371.38.w1)
An ovarian ultrasound study found that elephants are monovular. There were two follicular waves; the first occurred following the first LH peak and involved development of several small follicles (range 10 - 199 mm each, average 13.7 +/- 0.73 mm); these follicles were then replaced with ovarian tissue. After the second LH surge a single large follicle developed, average diameter 21.0 +/- 0.52 mm, significantly (P <0.01) larger than the multiple follicles; ovulation of this follicle occurred on the day of the LH surge or the following day, and a corpus luteum was formed following rupture of the follicle (22.5 +/- 0.81 mm). One to five days before the ovulatory LH surge, several structures, resembling corpora lutea, were observed. These were 14.3 +/- 1.2 mm, significantly (P<0.005) smaller than the CL which formed following rupture of the dominant follicle, and may result from luteinization of the first wave of follicles. During the luteal phase, both the post-ovulatory CL and the non-ovulatory luteal structures were imaged, developing to round-to-oval homogeneous, medium to medium-high echogenicity structures, 10 - 38 mm diameter (average 21.9 +/- 1.1 mm), with maximum diameters in week four of the luteal phase. When the luteal structures declined in diameter there was a corresponding decline in serum progesterone concentrations. All luteal structures regressed by the early non-luteal phase. (J54.19.w3)
In the cycling African elephant, serial blood sampling has shown the following pattern of hormones: (J386.136.w1)
- There are two LH peaks, about three weeks apart, with ovulation induced by the second LH peak. Peak LH levels reached 5.3 +/- 1.1 ng/mL serum in this study. (J386.136.w1)
- FSH secretion shows a cyclic pattern, with highest concentrations at the start of the non-luteal phase, declining to reach the lowest concentration within four days before the second LH surge, remaining low immediately after the second LH surge, then increasing during the luteal phase. (J386.136.w1)
- Progestins are low during the follicular phase and increase following ovulation. (J386.136.w1)
- Prolactin levels increase during the follicular phase of the cycle, peaking about four or five weeks after ovulation, then declining again. (J386.136.w1)
- Oestradiol levels varied across the cycle, with average levels under 25 pg/mL, but spikes up to 65 pg/mL; in some individuals, increases in oestradiol were measured preceding the LH surges, but this was not detected consistently. (J386.136.w1)
- There are no differences in TSH, free T3, free T4, total T3, total T4 or cortisol related to the stage of the oestrus cycle. (J386.136.w1)
Oestrus lasts for about two to six days. (B147)
The period of heat may be as little as two days. (B451.4.w4)
In both Zambia and Uganda, most conceptions (nearly 88% in Zambia) occur during the rainy season. (B147)
It is thought that ovulation may be stimulated by the change from the low crude protein level of the dry season diet of browse and dry grass to the higher protein content of the diet of fresh green grass at the height of the rainy season. (B147)
Females remain fertile to about 55 to 60 years old. (B147)
Oestrus last from two to six days in African elephants; it may possibly last up to 10 days. (B384.5.w5)
Oestrus cycles have been recorded as about 16 days long in captive African elephants. In Amboseli, the interval between heats if a female failed to conceive was found to be about three months. (B384.5.w5)
Elephants are monovular and polyoestrous; they undergo several sterile oestrus cycles prior to conception; it is not clear whether these cycles have associated signs of oestrus. The corpora lutea from these cycles do not regress but remain, therefore with each cycle another corpus luteum is added, until pregnancy occurs. Each cycle may last two to three weeks and a series of cycles may last about two months. (B453.6.w6)
Elephants are monovular and polyoestrous. Oestrus cycles last two to three weeks and are repeated for about two months, unless an egg is fertilised. The first three or four cycles are sterile. (B451.4.w4)
Females may have sterile oestrus cycles prior to a fertile cycle and conception. (B387.w4)
There is a variable period of anoestrus after parturition. (B453.6.w6)
There is a lactational anoestrus and female elephants generally do not come into oestrus until their calf is about two years old. (B387.w4)
Females are most fecund at 25 - 45 years of age. (B285.w3)
Female African elephants are most fertile at about 18 to 19 years old, with declining fertility after 40 years old, although they may remain reproductively active to 52 years. (B384.5.w5)
- In a population in Uganda, peak fertility was at 30 to 40 years, with declining fertility after 45 years and no conceptions by 55 years. (B384.5.w5)
- In the Kruger, of cows more than 50 years old, 88% of 42 animals were lactating and pregnant; one cow was 60 years old and was pregnant but not lactating. (B384.5.w5)
- In Amboseli, births have been recorded to mothers as old as 52 and 58 years, but the calves did not survive. (B384.5.w5)
Females may remain reproductively active into old age. One elderly herd matriarch, with a young suckling calf at foot, was thought to be more than 60 years old and possibly as old as 70 years. (B453.8.w8)
Poor nutrition may lead to decreased fertility. (B387.w4)
At Amboseli, the conception rate was 50 to 70%. (B384.5.w5)
Conception may be less successful in drought conditions. (B384.5.w5)
Conception rates may be decreased where poaching has greatly reduced the population of adult males. (B384.5.w5)

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Gestation / Pregnancy

Source Information

SUMMARY: Gestation generally lasts about 22 months; from zoo data a gestation length averaging 660 days has been determined while the average in one wild population (Amboseli) was 656 days.

Average gestation period of African elephants is 22 months; the recorded range is 17 to 25 months. (B147)
Average gestation length of African elephants is 656 days. (B285.w3)
Average gestation period of elephants is 630 days. (B285.w3)
Gestation length from zoo data is about 660 days in African elephants. (B384.5.w5)
Wild African elephants in Ambosli were observed to have a gestation length of 652 to 660 days with an average of 656 days. (B384.5.w5)
Gestation length is about 22 months. (B453.6.w6)
Gestation lasts about 660 days or 22 months. (B451.4.w4)
Gestation lasts 21 to 22 months. (B387.w4)

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Parturition / Birth

Source Information

SUMMARY: The cow may or may nor separate from her group before giving birth. Other females often gather around the calving cow. The cow is restless before the birth and may scrape the ground (the effect is to remove twigs and pebbles from the area where she is standing, although opinions differ as to whether this is deliberate). Usually, the birth itself is quick, although a labour of four hours has been observed in the wild. In a watched birth of twins in the wild, the calves were born twenty minutes apart. The umbilical cord ruptures as the calf drops to the floor. The fetal membranes are removed by the mother and/or other females, not always gently, and the mother (and sometimes other females) encourages and assists the calf to stand, using feet, trunk and tusks.

Seasonality: Births may occur all year but there is generally a peak in births just before the peak of the rains. This timing allows good lactation (due to the growing grass) as well as providing cover and cool conditions for the very young calf.

Parturition:

Other females gather round during the birth. "Midwives" may assist in removal of the fetal membranes, and females may also assist the calf to stand for the first time. (B285.w3)
Usually birth is quick. Labour is not always easy and may take e.g. four hours. (B384.5.w5)
The female remains with her family herd during parturition. (B384.5.w5)
During labour, the cow may repeatedly walk a few paces backwards and then kneel with the hindlegs, lie down, then get up again. (B384.5.w5)
There may be considerable interest from other elephants when the calf is born. (B384.5.w5)
The fetal membranes are removed by the mother or by the mother plus another females. This process is not always gentle. (B384.5.w5)
The mother prods the calf with her trunk, tusks and feet, encouraging it to stand. Other females may also assist. (B384.5.w5)
The mother may eat some of the fetal membranes. (B384.5.w5)
In a birth of twins seen in Kruger Park, the whole process of birth took 30 minutes, with 20 minutes between the birth of the two calves. (B384.5.w5)
Other females, who would normally be the mother, sisters, aunts or cousins of the cow, often with their own calves, commonly are present during the birth. (B453.6.w6)
Parturition is usually rapid. (B453.6.w6)
- A prolonged and apparently difficult parturition lasting four hours has been observed in the wild. (B453.6.w6)
The cow becomes restive, looks for a cool, sheltered spot, and scrapes the ground with a forefoot, which removes twigs, pebbles etc. Remaining standing, the cow may sometimes raise one hind leg. The calf emerges head first and the umbilical cord ruptures as it drops. The cow then turns, examines the calf with her trunk and caresses it with a forefoot; these actions remove any membranes and may stimulate respiration. The afterbirth is produced just after the calf is born or within 45 minutes of the birth. The placenta is not eaten but may be rubbed into the sand using a forefoot. (B453.6.w6)
In an observed birth of twins in the wild, the second calf was born about 20 minutes after the first calf. (B453.6.w6)
The cow may or may not separate from her group prior to parturition. (B451.4.w4)
The cow does not make any special preparations for parturition. (B451.4.w4)
Labour may sometimes be very tiring. (B451.4.w4)
Females may remain with the group or be alone for the birth. If with the family, the other elephants may form a defensive circle. They will often be very keen to touch the calf and help it to stand. (B387.w4)
Females left behind by movement of the group while the calf is unable to follow may break and toss vegetation, due to tension. (B387.w4)

Seasonality:

Births may occur at any time of year, but there is a peak of births just before the height of the rainy season. At this time the environment is cool and there is abundant cover for the calves. (B147)
Births generally occur early during the rainy season; the presence of plentiful green food means that the calf's dam can lactate adequately. (B285.w3)
A study of populations in East Africa found that for the Murchison Falls National Park (Uganda) North bank population, about 73% of births occurred December to March (low rainfall) while 72% of births on the South bank occurred April to July (high rainfall). It was noted that lactational demands are not maximal at birth and it was considered that the differing birth seasons were related to the environmental effects of fertility and season of conception [see above: Breeding Season]. (P17.21.w1)
Births generally occur early in the rainy season, as the rains are increasing, which is when grass is growing well. (B451.4.w4)
Births may occur all year but in many areas a distinct peak is seen just prior to the peak of the rains; this provides young calves with cover and cool conditions, and ensures that they are several months old before they have to cope with drought. (B387.w4)

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Neonatal Development

Source Information

SUMMARY:

Elephant calves are precocial; they attempt to stand almost immediately and may stand after a period of a few minutes to an hour or more (about thirty minutes may be average). Once on their feet they search for the nipples and suckle using their mouth (NOT the trunk).
The ears are tight against the head at birth.
Male calves generally grow faster than do female calves; from 0.85 m at birth the calf may reach 1.1 - 1.5 m by one year old. Hand-reared calves grow more slowly than do mother-reared calves, but calves in captivity may grow faster after weaning than do wild calves, due to better nutrition and reduced parasitism.
The first cheek tooth cuts the gum when the calf is about six weeks old and is lost at one to two years.
Calves suckle frequently, every hour or less, for about 1.5 minutes at a time. Suckling becomes less frequent when the calf is about six months old. They continue suckling to at least two years old, and rarely survive if they lose their mother before this age. Calves may still suckle at three and a half or four years or even older.
Calves start to play with vegetation very early, and may investigate and sample food from their mother's mouth, but only start to actually swallow some grass at about four months. They are eating a significant amount of vegetation by six months and by two years they spend as much of their time eating as the adults do. They can manipulate sizeable branches by about six to ten years of age.
Calves first start to drink water with their trunks from about three months old.
Calves may initially have poor trunk control and may be shaky on their legs for the first few days, but can move with the herd usually from about two days old. Calves remain very close to their mother for about the first six months, then begin to move further away, to explore and to play with other calves. Young calves play vigorously with bouts lasting 30 to 50 seconds; older juveniles play less. Play includes chases, rolling over each other, mock fights, gambolling and mounting one another.

Birth:

Elephant calves are precocial; they can stand by about 30 minutes after birth. (B147)
Elephant calves are precocial, in that they are able to stand within minutes to a couple of hours after birth. At this time they still have poor limb coordination, often stumbling and falling, and poor vision, using smell, touch and sound to find its mother. Searching for the teats initially takes place randomly between the front and hind legs. (B396.4.w4)
With an inexperienced mother, it may be as long as four hours before the calf finds the teats. (B384.5.w5)
The calf attempts to stand almost immediately after birth and the mother assists. It is able to stand after about 15 to 29 minutes but may fall several times before getting its balance; it then searches for the teats; when it finds these it suckles with the trunk hanging to one side, uncontrolled. (B453.6.w6)
The strength of newborn calves may be very variable: some stand within a few minutes, others not for an hour or longer. (B387.w4)

Eyes and ears:

At birth, the ears are tight against the head. (B453.6.w6)

Thermoregulation:

Growth rate/weight gain:

Hand-reared calves grow more slowly than do mother-reared calves. (B10.49.w21)
After weaning, elephant calves in captivity may grow faster than wild calves, due to better nutrition and less parasitism. (B10.49.w21)
By six years old, the young elephant may weight a tonne. Growth is slower from about 15 years old, but still continues throughout life. (B285.w3)
Growth rate of males is faster than that of females. (B285.w3, B396.4.w4)
Growth and weight gain is faster in captive elephants than in wild elephants. This may be related to the greater amount of exercise taken by wild elephants. (B384.5.w5)
At one year old the calf is about 1.1 to 1.5 m tall. (B384.5.w5)
Growth rates reduce with age. In the African female elephant, growth rate is greatly reduced after puberty (at about 10 to 15 years of age. (B384.5.w5)
Male elephants (African and Asian) at about 20 years old appear to undergo a second growth spurt, for about five years. (B384.5.w5)

Tooth development:

The first molar cuts the gum when the calf is about six weeks old and all four are in use by the time the calf in 8.5 weeks of age. The second molar comes into wear when the calf is two years old, the third at five years, the fourth at nine or ten years of age, the fifth when the elephant is 20 years old and the sixth tooth comes into use when the animal is 30 to 40 years old. (B384.3.w3)
The first molar is lost at one to two years of age, the second at two to four years, the third at nine to 10 year, the fourth at 19 to 25 years and the fifth at about 43 years; the sixth, which starts erupting when the elephant is about 30 years old, is lost at about 60 years. (B384.3.w3)

Feeding, exploration and dispersal:

Suckling and weaning
- Calves suckle as soon as they can stand and find the mammary glands. They suckle small quantities at frequent intervals. Suckling continues for at least two years, however older calves, e.g. three years of age, may also be seen suckling alongside a younger sibling. (B453.6.w6)
- Young calves suckle frequently, e.g. every 37 minutes for bull calves and every 60 minutes for female calves. (B384.5.w5)
- The calf suckles using its mouth (not the trunk). (B384.5.w5)
- Each suckling bout lasts about 1.5 minutes. (B384.5.w5)
- The calf requires about 15 litres of milk per day. (B384.5.w5)
- Suckling decreases in frequency when the calf is about six months old. (B384.5.w5)
- Mothers rarely encourage their calf to find the nipple, but they are tolerant of the calf's suckling. (B384.5.w5)
- Calves are usually weaned at about six to eighteen months old, but may still nurse occasionally to six years or older. (B147)
- Calves are completely nutritionally dependent on their mothers to three months old. Having started to eat vegetation, the calf continues to suckle at the same rate as before to six months old. It still depends on milk as one source of nutrition to two years of age and usually gets significant nutrition from milk to at least three years of age. (B396.4.w4)
  - To about one year of age, elephant calves suckle for two to four minutes per hour - a high rate for an ungulate. (B396.4.w4)
- Calves are dependent on milk to about two years old but may continue suckling to 3.5 years old. (D301.1.w1)
- Elephant calves consume milk as the main part of their diet for about two years, and this continues as part of their diet to three or four years old. (B285.w3)
  - If the mother dies, the calf usually dies; other females will not let it suckle at the expense of nutrition of their own calves. (B285.w3)
- Weaning occurs gradually. (B396.4.w4)
- Weaning occurs over the period six to eighteen months, although animals as old as six years of age or older may still suckle. Mothers may vary in their tolerance for suckling by older calves. (B387.w4)
- Females have been observed to tolerate older offspring suckling, even at the age of seven or eight years. (B384.5.w5)
- Weaning starts when the calf is a few months old but is not complete until the calf is about two years old. Juveniles as old as nine years of age may still try to suckle alongside younger siblings. (B451.4.w4)
- African elephant calves are unable to survive if orphaned at under two years of age; the youngest know such survivor was 26 months old at the time of its mother's death. (B384.5.w5)
Feeding and drinking:
- Calves start to play with vegetation at a very early age, picking up and playing with leaves and grasses dropped by the cow. (B453.9.w9)
- Calves are totally dependent on their mother for the first three months. At this age they start trying to take vegetation; at four months they may swallow some grass, and may kneel and bite at grass. Calves imitate their mother in feeding; they investigate the contents of their mothers' mouths with their trunks and occasionally take some of this food and eat it. By six months old the calf is eating a significant amount of vegetation. By two years old calves spend as much time eating vegetation as adults do. (B384.5.w5)
- A calf will put the end of its trunk into its mother's mouth and take food from there. It will eat some vegetable material from about six months old. (B285.w3)
- From three months, some vegetation is eaten; more after this time, with skill at feeding independently improving and all the basic feeding skills mastered by the time the calf is a year old. (B396.4.w4)
- Calves learn which food to eat by sampling food types they see eaten by other members of the herd. (B285.w3)
- By about six to ten years old, juveniles may uproot bushes and manipulate sizeable branches while feeding. (B453.9.w9)
- Initially, calves drink water using their mouth; sucking water with the trunk starts in the fourth month; only some of the water is successfully transferred to the mouth, but by one year, the calf has fully developed this skill. (B396.4.w4)
- Calves start trying to drink water using their trunks from about three months old, but take about a year to succeed in this. (B384.5.w5)
- Even young calves will imitate their mothers in trying to dig water holes in dry sandy river beds. Older calves may be able to dig a hole but in severe droughts rely on deeper holes dug by adults. (B453.9.w9)
Movement, exploration and play:
- Newborn calves appear almost helpless and not to have proper control of their trunks. (B384.5.w5)
- In the first week, an elephant calf appears to have little control over its trunk. It may be wriggled rapidly, the calf may fall over it, but it is not useful. Control is better even in the second week and has improved substantially by the time the calf is a month old. (B396.4.w4)
- Very young calves lean heavily against their mothers' legs, keeping contact with her. (B387.w4)
- Most calves can walk well after three days; some may still be shaky in the legs for up to a month. (B387.w4)
- Calves can move with the herd when they are about two days old. (B147)
- By the second week, calves walk better and are even able to run short distances. (B396.4.w4)
- Young calves are rarely out of touching-distance of their mother. (B285.w3)
- Calves start to use their trunks to pick things up from about one week old. (B384.5.w5)
- To about six months of age, the calf remains close to its mother. (B453.9.w9)
- Small calves remain close to their mothers; by the time they are half grown the attachment is so much looser that it may be difficult to determine which cow is the mother. (B462.4.w4)
- From about six months old the calf starts to move further from its mother, exploring and tasting different leaves, for example. It is vulnerable at this time to being left behind if the herd is disturbed/stampeded, and is also most vulnerable to predators. (B453.9.w9)
- From about a year old, calves have to manage difficult terrain without assistance from their mother's trunk. However, they may still hold the tail of their mother, sister or aunt for assistance up a steep bank. (B453.9.w9)
- The calf keeps close to its mother (on average within 2 metres) until it is about eight years old. (B384.5.w5)
- Calves play using head-to-head sparring, trunk wrestling, mounting one another and chasing and rolling on one another. (B384.5.w5)
- Play is most vigorous and last longest (30 to 50 seconds) in young calves, and is less vigorous in older juveniles. (B384.5.w5)
- As yearlings, calves play with one another, with trunk slapping, mock fights, tumbling over and gambolling. (B453.9.w9)
- Teenage bulls may mount one another during play, sometimes with an erect penis. (B453.9.w9)
- If captured, calves as young as one or two years old may be aggressive initially, but soon settle (within days). (B453.9.w9)
- By as young as seven or eight years old, juveniles ca already give some threatening display and may, in the absence of an adult, even charge. (B453.9.w9)
- Calves learn to swim quite early when the elephants bathe in deep water; it is not known whether they swim instinctively or have parental assistance in learning to swim. (B453.9.w9)
- Calves learn bathing routines from their mothers; they also learn from the adults about mud and dust bathing, to give an earth pack over the skin. (B453.9.w9)
- Calves may be fearless in their explorations. (B387.w4)
- Calves go to one another and play wrestle and pushing etc while the family rests or drinks. (B387.w4)
- Elephant calves play as an important part of their development. This includes for male calves, chasing and sparring head-to-head; females tend to play by running through long grass, chasing birds, throwing sticks and attacking imaginary enemies. Calves of both sexes, particularly when juvenile, play games involving climbing over one another. (B285.w3)

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Litter Size

Source Information

SUMMARY: There is usually one calf but about 1% of pregnancies may produce twins.

One calf is usual; one to two percent of births may involve twins. (B147)
One calf is usual; about 1% of births may involve twins in both African and Asian elephants. There is one record of triplets in a shot elephant [species of elephant not given]. (B384.5.w5)
- In Namibia, nearly 5% of births were twins, including one pair of non-identical twins. (B384.5.w5)
A study of populations in East Africa found winning rates of about 2.78 +/- 3.87% (2.17% of 46 pregnancies from Murchison falls and 3.84% of 26 pregnancies from Tsavo. Twin pregnancies from Murchison Falls were noted to be dizygotic, with separate placentae in the two uterine horns. Adding data from a further 63 records from other studies gave an estimate of 2.23 +/- 2.51%; the authors considered that, given the lack of previous records of twins, the true incidence was probably less than 1%. (P17.21.w1)
Single calves are usual but twins do occur. (B453.6.w6)
Usually one. (J68.361.w1)

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Time between Litters/ Litters per year

Source Information

SUMMARY: The minimum possible calving interval is about two years, however there may be a lactational anoestrus, (i.e. the female does not come into oestrus while she is lactating) while the calf is suckling, increasing the inter-birth period to three or four years (less if the calf dies and suckling stops) . Longer inter-calf intervals may occur in conditions of poor nutrition or overcrowding, giving inter-calf intervals of sever years or longer.

Females calve at intervals of 2.5 to nine years; usually there are about five years between births. (B147)
Females may calve about every three to four years. (B285.w3)
Females may conceive as early as nine months after calving. (B384.5.w5)
In general, the calving interval in African elephants ranges from 2.75 to 13 years. Intervals vary between populations: in Amboseli, five years was average, while in Uganda in an overcrowded population the interval was nearly seven years. (B384.5.w5)
In Amboseli in 1973 to 1978, when females were in poor condition, the calving interval increased to six years. (B384.6.w6)
A study of populations in East Africa calculated for the Murchison Falls National Park, Uganda, a parturition to conception interval of 33.5 months and a 4.5 year mean calving interval, while for the Tsavo National Park, Kenya, the calculated parturition to conception interval was 59.8 months and the mean calving internal 6.8 years. (P17.21.w1)
Note: Estimates of calving interval may be affected by climatic conditions in the years prior to sampling: one or two years of poor fertility before sampling will produce a long estimated calving interval, while two or more fertile years will provide a short estimate. Additionally, the long gestation internal may result in alternating years of many and few births, related to e.g. good reproductive success in one year (with conditions good for high fertility) being followed naturally by few births the following year. (P17.21.w1)
The basic inter-calf period is about 2.0 - 2.5 years; a single cow elephant may be observed with two or three calves at foot, and be pregnant. Successive calvings at 123 weeks have been recorded for a captive elephant. In some areas there may be a lactational anoestrus of about two years following parturition, which would give an inter-calf interval of at least four years. (B453.6.w6)
A study in Uganda found a period of two years of lactational anoestrus after birth, which would give at least four years between births. (B451.4.w4)
Data on calving interval in most studies has been based on the number of placental scars (indicating the number of pregnancies over the life of the female) or, to give an instantaneous calving interval for the population, the percentage of females in the sample which were pregnant. Various studies have estimated the instantaneous calving interval as 2.9 to 9.1 years and the interval based on placental scars as 3.4 to 5.1 years. (B451.4.w4)
- It should be noted that a very short instantaneous calving interval for a population is likely to be followed by a longer such interval in the following year, due to the long gestation. (B451.4.w4)
- It would appear that the "ideal" calving interval is four years, and that marked deviations from this are due to nutrition, with reduced fertility when food availability is reduced. (B451.4.w4)
Calving intervals may range between 2.5 and nine years. The calving interval may be reduced if the calf dies, due to cessation of lactational anoestrus. (B387.w4)
The inter-calf interval is 3.5 - 4.0 years. (D301.1.w1)
Depending on population density and availability of food, the intercalf interval is four to eight years. (J68.361.w1)

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Lactation / Milk Production

Source Information

SUMMARY: Calves are generally basically weaned by about two years old; lactation may continue during the next pregnancy but ceases before parturition with the mammary glands then developing visibly again about seven weeks before calving. Elephant milk is considered to be moderate in its contents of dry matter, fat, protein and carbohydrate.

Lactation in elephants continues past the next conception, but ceases prior to the next calving. The breasts develop visibly about seven weeks before calving. (B384.5.w5)
The composition of elephant milk has been reported as approximately: water 82%, fat 7%, protein 4%, lactose 6.5%, ash 0.5% with vitamins A, B and D at levels similar to that seen in cattle and a level of vitamin C four times that of cattle. [No information was provided regarding the stage of lactation] (B453.6.w6)
Calves are sucked for several years. (B451.4.w4)
Elephant milk is "moderate" in its dry matter, fat, protein and carbohydrate contents. (P3.1987.w3)

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Sexual Maturity

Source Information

SUMMARY: In optimum conditions, elephants may become sexually mature at about 10 or 11 years old. Both nutritional and social factors may affect sexual maturity, so that puberty may be delayed to about 16 - 18 years of age in drought conditions or in an overcrowded population. Males, although they may be producing sperm at as young as 10 - 13 years, are unlikely to be able to compete successfully with other males and actually mate a female under about 20 years of age.

Females may become sexually mature at 11 years old in optimum conditions, but sexual maturity can be delayed to as old as 22 years. (B147)
Males may become sexually mature at 10 years old in optimum conditions, but sexual maturity can be delayed to as old as 20 years. (B147)
- Males cannot successfully compete to mate until they are more than 20 years old. (B147)
Females may reach sexual maturity at about 10 years of age, but in periods of drought, or in high population density, them may not enter oestrus for several more years. (B285.w3)
Females reach sexual maturity at nine to 18 years old; the average is probably 12 years old. (B384.5.w5)
- Conception has been recorded at seven years old. (B384.5.w5)
- At Amboseli, in a relatively undisturbed population, the earliest recorded age of conception was 10 years. (B384.5.w5)
- During a period of drought at Amboseli, puberty was delayed to 16 to 17 years. (B384.6.w6)
Defining puberty as the onset of the first oestrus cycle (at least one large follicle develops), and sexual maturity as the age at first ovulation (indicated by the presence of at least one corpus luteum), there may be two to four years between puberty and sexual maturity in female elephants. In different elephant (African and Asian) populations, the mean age at sexual maturity may be as young as nine or as old as 22 years; 11 to 14 years is typical for wild female elephants. (B396.3.w3)
Females reach puberty at 10-12 years of age. (J68.361.w1)
Based on samples from the vas deferens, examined under a high power microscope, puberty in male elephants was determined to occur at 13 to 16 years (mean 14.5 years) for elephants from Tsavo National Park, Kenya, about 13 to 17 years (mean 15 years) for those from Murchison Falls National Park North bank, Uganda and 18 to 21 years (mean 19.5 years) for elephants from Murchison Falls South bank. (P17.21.w1)
A study of elephants from three populations in East Africa determined sexual maturity in females based on the presence of either a corpus luteum or an ovulation stigmata as indicating sexual maturity, and the presence of at least one follicle more than 5.0 mm in diameter as "pubertal". The study indicated that for elephants from the Murchison Falls National Park, Uganda, there was a potential mean age at puberty of about 11 years old, with those from the North bank being "pubertal" at six to 15 years and those from the South bank at six to 22 years. It was suggested that females from both populations probably could essentially have ovulated at about 11 years of age but that full maturation of follicles, and ovulation, was inhibited "by physiological, nutritive or social stresses" and was retarded more in the South bank than in the North bank population. (P17.21.w1)
- At puberty, females from the North bank had reached 218 cm at the shoulder (85.2% of full adult height) and 1,730 kg (63% of full adult weight) and those from the South bank had reached 230 cm (89.9% of full adult height) and 2,040 kg (74.3% of full adult weight). Females from Tsavo National Park, Kenya, had reached 212 cm (82.8% of full height) and 1,830 kg (66.7% of full weight) at puberty. (P17.21.w1)
Note: estimated ages at puberty may be affected by age estimation: if two studies give different ages for the same general physical characteristics then they will also indicate difference ages at puberty even if the actual age at puberty is the same. (P17.21.w1)
Estimates of the age of puberty rage from eight to 13 years; some reported differences may be related to differences in age estimation. It is probable that females become pregnant at no younger than 10 years and give birth at no younger than 12 years of age. (B453.6.w6)
Sexual maturity occurs normally at about 11 or 12 years old in both males and females, but is very variable depending on resources. (B451.4.w4)
- In Uganda, in Kabalega Falls National Park, sexual maturity was delayed to 17 - 18 years old, and in Budongo Forest, to 22 years. (B451.4.w4)
- Females are mated soon after their first ovulation, and give birth to their first calf two years later. (B451.4.w4)
- Males reach sexual maturity at the same age as do females, but do not reach social maturity, and have a chance to mate, until much older. (B451.4.w4)
Defining puberty in males as the time viable sperm are first produced, and sexual maturity s when a dense mass of sperm is produced, male elephants may reach puberty at eight to 15 years old, depending on the population, with sexual maturity about two to three years later. (B396.3.w3)
The age of puberty may be affected by nutrition and by social factors. (B387.w4)

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Male Seasonal Variation
Source Information	SUMMARY: There does not appear to be any males reproductive seasonality. After puberty, spermatogenesis does not cease. (B453.6.w6) *For information about musth see African Elephant Loxodonta africana -* Sexual Behaviour (Literature Reports)**

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Longevity / Mortality

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SUMMARY: Wild elephants may reach about 60 years of age; in captivity this might be extended to as long as 80 years. Recent data from one study suggested that calf survival to one year may be as high as 95%, although other studies have reported mortality rates as high as 10% or even 36%. Twins are rarely raised successfully. Survival may be higher for calves which have "allomothers" or "aunties". After weaning, the mortality rate may be about 5.1 - 6.6% per year to about 50 years. Mortality then rises sharply as the last molar is used up, with deaths generally occurring during the dry season since dry food cannot be effectively sheared by the remaining, smooth, grinding surface. In drought years mortality is increased; the effect on animals of different age classes may vary; bull calves, with higher growth rates and nutritional needs, are more likely to die during drought than are female calves. Deaths during drought are often from starvation rather than dehydration, with elephants, reluctant to leave a known water source, running out of vegetation in the local area. The greatest vulnerability to predation by lions, hyenas and hunting dogs is just after birth, and also when the calf starts to stray further from its mother at about six months old. As well as natural predation, elephants may die from hunting, poisoning due to eating toxic plants, disease, accidents, starvation, drowning, heat stress, and congenital malformation; snake bite is another possible cause of death.

Recent data, based on 13 mothers and their calves, showed more than 95% survival to one year old. (B285.w3)
Mortality in the first two years of life is decreased for calves which have "aunties" or "allomothers". (B384.5.w5)
Mortality may be high in the first year, with rates in Uganda reported as 36%. (B384.5.w5)
Mortality of calves more than one year old is low. (B384.5.w5)
In dry years, bull calves die more than do female calves, possibly due to a higher growth rate and therefore higher food requirement. (B384.5.w5)
Just after birth the calf is most vulnerable to predation from lions, hyenas and hunting dogs: although its mother will defend it, the calf may not be able to keep in the secure position under its mother's abdomen. (B453.6.w6)
From about six months old, when the calf starts to move further from its mother, it is vulnerable to being left behind if the herd is disturbed/stampeded, and is also most vulnerable to predators. (B453.9.w9)
Twins are rarely reared successfully; they usually die within a few months of birth. (B384.5.w5)
The mortality rate after weaning is about 5.1 to 6.6% per year until 50 years, when it rises sharply as the last molar wears away. (B384.5.w5)
Deaths due to old age usually occur during the dry season, since in elephants where only a small portion of tooth is left (about seven cm by 10 cm), the grinding surface is smooth and dry food cannot be sheared effectively. (B384.5.w5)
Males may die in water after trying to feed on soft aquatic plants. (B384.5.w5)
A study of the Amboseli population (not hunted) from the 1950s to the 1980s found mortality as follows: (B384.6.w6)
- In wet years 7.5% to one year old, 15% by 2.5 years of age;
- In dry years to one year old, 10% for female calves and 25% for males.
- For the next two to five years, 12%.
(B384.6.w6)
For Tsavo Park in 1959 to 1970, tusks collected from elephants which died naturally indicated an estimated one in three mortality to one year and one tenth from one to five years, then 2% to 3% per year for cows from six years to 45 years and in bulls from six years to 25 years. (B384.6.w6)
In drought conditions, mortality is increased. In different situations, age classes affected have been noted:
- In Amboseli (drought in 1975 to 1976), in 1976 about half the calves under two months of age died, probably due to decreased milk quantity and quality, as did half the calves of five to six months, when they would have been starting to eat vegetation. Mortality was also higher in animals of four to five years, possibly recently weaned calves. (B384.6.w6)
- In Tsavo East in 1970-1971, about 5,900 of 20,000-25,000 in the area died. Mortality was highest in cows, particularly mature cows, and in calves under five years of age, particularly those three years old or less, while only 10% of those dying were adult bulls. High mortality among calves continued to 1974. (B384.6.w6)
- In Ruaha Park, young animals, either without tusks or with tusks less than 2.0 kg in weight, showed highest mortality. (B384.6.w6)
- In Zimbabwe, during the very dry year 1982, many elephants died around a natural waterhole. Most deaths were in elephants two to eight years of age; the following year was also dry and most deaths were of adult cows. (B384.6.w6)
During drought, deaths are probably from starvation, since elephants are reluctant to leave known water sources to find food. (B384.6.w6)
During drought, deaths may also be related to heat stress. (B384.6.w6)
At Manyara estimated mortality was 10% for the first year and 3% to 4% each year thereafter. (B384.5.w5)
Life expectancy for African elephants is about 50 to 70 years. (B147)
Longevity is about 60 years in the wild and may be more than 80 years in captivity. (B285.w3)
In the wild, elephants probably usually live to about 50 years old and probably have a potential 65 year life span. (B384.6.w6)
In captivity, the maximum age which has been reached by an African elephant is 44 years. (B384.6.w6)
The limit to elephant age appears to be the teeth: there are six sets of molars; once the sixth set has worn out the elephant will starve to death since it will be unable to feed itself properly. The last set of molars wears when the elephant is 50 to 70 years old. (B10.49.w21)
Elephant populations may, in favourable conditions, increase at four to five percent per year; 7% has been recorded. (B147)
In a study in East Africa, it was noted that the oldest female in a given population was about 10 years older than the oldest male for the same population, indicating a sex-specific survival rate difference. (P17.21.w1)
From a study of populations in East Africa, it was noted that annual mortality rates of adult elephants in various populations was about 4.0 - 5.0%. The rate for calves was higher and more variable: in Murchison Falls National Park (Uganda) in 1965, cumulative mortality to about 2.0 - 3.0 years was about 38% in the North bank population and 24% in the South bank elephants. (P17.21.w1)
Calf mortality may be increased due to nutritional deficiencies and/or heat stress when ranges are restricted and habitats change, with browse and shade becoming less available. (P17.21.w1)
Causes of death include "disease, accidents, starvation, drought, stress, heat stress, drowning, snake bite and congenital malformation" as well as predation. (B384.5.w5)
A female was seen which had died after falling 400 yards down a steep slope. A bull died after a baobab, weakened by elephants, fell on him. One male was found apparently dead from a fight, since a deep, tusk-sized hole was present, piercing the brain. Calves were sometimes predated by lions. (B462.16.w16)
It is possible that in some areas elephants may reach 80 years or possibly even 100 years. (B453.6.w6)
Elephants of all ages may be predated by humans. (B453.7.w7)
Elephants with driver ants in their trunks may "run amok and beat itself to death." (B453.7.w7)
Elephants may die after eating poisonous vegetation. (B453.7.w7)
Elephants may be killed by snake bite. (B453.7.w7)
Elephants will die when the last molar is practically used up. (B453.7.w7)
Elephants may die of "misadventure" including falls, fights, drowning, fire and lightning. (B453.7.w7)
In captivity, elephants have died after falling into a narrow moat, after suffocating on a tennis ball which lodged in the elephant's mouth, and during flights (due to dehydration, shock, loneliness, fear and rough handling. (B453.7.w7)
Elephants appear able to cope with temperatures ranging from below freezing to 120 �F, if they have access to water and shade, and are free to move about. (B453.8.w8)
Elephants will die from starvation and malnutrition once the last molar is used up and food can no longer be properly chewed. (B451.1.w1)
Mortality rates may be higher for calves born in areas with poorer environmental conditions, and for calves born in the dry season rather than the wet season. (B387.w4)
Droughts can kill large numbers of elephants in the presence of water but absence of available food, so that animals die of starvation rather than dehydration. During drought, young and adult females die in the greatest numbers. (B387.w4)
Abortions occur in elephants. (B387.w4)
Females may die after late term abortion or while giving birth to full-term calves. (B387.w4)
Survival of female elephants is greater than survival of male elephants: there are more females than males in elephant populations and the difference in percentages of the two sexes increases in older age classes. (B396.3.w3)

Age Estimation Techniques:

Age can be determined in dead elephants on the basis of eruption stage, and to a lesser extent wear, of the cheek teeth in the mandible. This depends on correct identification of the individual teeth; plots of length against width produce six well-defined groups with little overlap. Thirty age groups can be determined by this methods and chronological ages then can be assigned to these age groups. (P17.21.w1)
Information on age and growth was taken from captive animals and a growth curve was constructed from these data. (P17.21.w1)
Data from a study of several hundred elephants shot in east Africa (400 from Murchison Falls National Park, Uganda and 300 from Tsavo National Park, Kenya), indicated that the effective upper age limit for African elephants in the wild was about 60 years. (P17.21.w1)
Measurements of shoulder height were taken by manipulating the foreleg until it locked straight, then measuring using a steel tape from the sole to the scapular crest, in a straight line (not following body contours, sighting along the dorsal edges of the two scapulae to ensure the reading was taken at the appropriate point. (P17.21.w1)
A method of accurate estimation of whole body weight from the weight of a dissected hind leg has been developed. It is thought that this may be more accurate than weighing dead elephants, particularly in pieces, due to variable losses of fluids in the whole weighings. (P17.21.w1)
For age estimation from the teeth, the lower molars are generally used, since these wear faster and more regularly than do the upper molars. (B451.1.w1)
Various methods of age estimation have been described. Some are useful only for a given population. Methods which have been used for age estimation of live elephants in the field include: (B453.6.w6)
- The circumference of the fore foot print;
- Shoulder height;
- Degree of ear turn-over;
- Measurement of body length from aerial photographs (valid only for a given population).
(B453.6.w6)
For estimation of the age of dead elephants, the degree to which the various molars are in wear has been used, however, interpretations have varied considerably. (B453.6.w6)
The "FM" technique describes the "molar age" of the elephant in terms of molar progression in relation to the fixed point of the foramen mentale in the lower jaw: which molar is passing this point and which lamina of the molar has reached the foramen. It was considered by the originator of this method that for elephants up to 30 years old it was possible to convert "molar age" to age in years with reasonable accuracy, but that after that age it was somewhat arbitrary, due to lack of true baseline data on the actual rate of molar progression and adequate data from older elephants. (B453.6.w6)

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Authors & Referees
Authors	Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee	Susan K. Mikota DVM (V.w72)

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