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Living OrganismsAnimalia / Craniata / Mammalia / Lagomorpha / Leporidae / Romerolagus / Species

Romerolagus diazi - Volcano rabbit (Click photographs/illustrations for full picture & further details)

Romerolagus diazi - Volcano rabbit. Click here for full page view with caption Romerolagus diazi - Volcano rabbit in pen. Click here for full page view with caption

INDEX - INFORMATION AVAILABLE

GENERAL & REFERENCES

APPEARANCE / MORPHOLOGY

LIFE STAGES / NATURAL DIET / PHYSIOLOGY

BEHAVIOUR

HABITAT & RANGE

CONSERVATION

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General and References

Alternative Names (Synonyms)

  • Conejo de Díaz (Spanish). (W2.Apr08.w73)
  • Conejo de los Volcanes (Spanish). (W2.Apr08.w73)
  • Lapin de Diaz (French). (W2.Apr08.w73)
  • Lapin des Volcans (French). (W2.Apr08.w73)
  • Teporingo. (B607.w20, J469.360.w1, W2.Apr08.w73)
  • Zacatuche. (B51, B607.w20, W2.Apr08.w73)
  • Romerolagus nelsoni. (B607.w20)
  • Lepus diazi (J469.360.w1)

Names for new-borns / juveniles

  • Leveret (B285.w5b)

Names for males

Names for females

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General Appearance

Adult:
  • Volcano rabbits are small rabbits with dark brown fur (dark brownish grey underneath), short rounded ears and short legs and feet; the tail is not visible. (J23.10.w4)
  • This is described as the second smallest leporid, with only Brachylagus idahoensis - Pygmy rabbit being smaller (B605.12.w12). However, the Volcano rabbit has also been described as being the smallest leporid. (B607.w20)
  • "...features include short ears, legs, and feet, articulation between collar and breast bones, and no visible tail." (B607.w20)
  • This species is considered by many to be the most primitive of the living leporids. (B605.12.w12)

Newborn:

  • Fine dark brown fur, laid-back ears and closed eyes. (J23.10.w4); the tail is visible at birth. (J469.360.w1)

Similar Species

  • "Romerolagus is unlike any other leporid in Mexico and actually bears a resemblance to Ochotona [Ochotona sp.], another lagomorph with short ears and limbs, no tail, and a propensity to frequent rocky, mountainous areas." (B147)

Sexual Dimorphism

--

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References

Species Authors & Referees

Author: Kathryn Pintus BSc MSc MSc (V.w115); Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee:
Dr Vicky Ahlmann (V.w142)

ORGANISATIONS

ELECTRONIC LIBRARY
(Further Reading)
Click image for full contents list of ELECTRONIC LIBRARY

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Husbandry Information

Notes

  • --

Management Techniques

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Appearance / Morphology

Measurement & Weight

Notes

Specific Romerolagus diazi Information

LENGTH
Adult:

  • 270-315 mm. (B147)
  • 27-36 cm. (B607.w20)
  • Males: 234 - 292 mm mean 268.3 mm. (J469.360.w1)
  • Females: 24 - 321 mm, mean 285.1 mm. (J469.360.w1)
  • Minimal sexual dimorphism, with females being only slightly (non-significantly) larger than males. (B605.12.w12, J469.360.w1)

Newborns:

  • Total length: Average: 93.8 mm; Range: 83-106 mm (Sample size = 5). (B287, J469.360.w1)

HEIGHT
Adults and sub-adults: --
Juveniles: --

WEIGHT
Adult:

  • 387-602 g. (B147)
  • 400-500 g. (B607.w20)
  • 500 g. (B605.12.w12)
  • Males: 386.6 - 479.1 g (mean 417.4 g). (J469.360.w1)
  • Females: 462.1 - 602.5 g (mean 535.9 g). J469.360.w1
  • Data from captive-bred animals in Japan: 400 - 600 g. (J511.31.w1)

Newborns:

  • 23-32 g. (B147)
  • Average: 24.1 g; range: 22.6-25.0 g. (Sample size = 5). (B287, J469.360.w1)
  • Female: 25-27 g. (J511.31.w1)
  • Male: 32 g. (J511.31.w1)

GROWTH RATE 

  • Data from captive-bred young at Chapultec Zoo, Mexico City.
    • Young estimated to be about 20 days old weighed about 80g. (J23.26.w2)
    • A male weighed 440g at about 6.5 months of age. (J23.26.w2)
    • At eight months old, females weighed 410 - 650 g. (J23.26.w2)
  • Data from captive-bred animals in Japan:
    • Increasing from 25-27 g for females and 32 g for males at birth to 80-130 g for females and 95-128 g for males by three weeks old. (J511.31.w1)

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Head and Neck

Notes

GENERAL HEAD STRUCTURE:
Adult:

Specific Romerolagus diazi Information

  • "The skull of Romerolagus, like that of Ochotona [Ochotona sp.], has no anterior bony projection above the eye socket, but in most other characters it resembles that of Sylvilagus [Sylvilagus sp.]." (B147)
  • Ears: The ears are small and rounded. (B147, B605.12.w12, J469.360.w1)
    • 40-44 mm. (B147, B607.w20)
    • 40 - 45 mm, mean 43.1 mm from notch (seven females). (J469.360.w1)
    • 41 and 44 mm (two males). (J469.360.w1)
    • Mean 36 mm (six adults). (J469.360.w1)

Newborn: 

Specific Romerolagus diazi Information

  • Ears laid back at birth. (J23.10.w4)
  • Ear length 9.3 mm (range 8.0 - 10.5 mm). (J469.360.w1)

DENTITION:

General Information

  • Rabbits and hares have a total of 28 teeth. (B285.w5a)
    • The dental formula for rabbits and hares is i 2/1, c 0/0, pm 3/2, m 3/3 x 2 = 28. (B147, B285.w5a)
  • The lower tooth rows are closer together than the upper tooth rows. (B147)
  • Lagomorphs differ from rodents by having two pairs of upper incisors rather than just the one pair. The additional set of incisors are called peg teeth and are found directly behind the long pair in the upper jaw. (B147, B285.w5a, B605.1.w1)
  • At birth, lagomorphs actually have three pairs of upper incisors, but they quickly lose the outer incisor on each side. (B147)
  • The incisors are covered completely by enamel. (B147)
  • The upper incisors' roots are found in the skull's premaxillary bones. However, the length of the lower incisors' roots varies. (B147)
    • [Note: lagomorphs have teeth which grow throughout their lives. For this reason the portion of the teeth which is not exposed (not above the gum line) is strictly speaking not a "root"; however, it is sometimes convenient to describe it as a root.]
  • The first upper incisors have a cutting edge which is V-shaped. (B147)
  • The peg teeth lack a cutting edge. (B147)
  • On the anterior surface of the upper incisors of the vovano rabbit is a deep groove which is not filled with cementum. (J469.360.w1) 

EYES:
Adult:

General Information

  • Lagomorph eyes are positioned such that they allow for good broad-field vision. (B285.w5a)
  • Hares and rabbits have large eyes which are adapted to both their crepuscular and nocturnal activity patterns. (B285.w5b)
  • Leporids have "large eyes to increase visual acuity in dim light." (B430.w2)

Newborn:

Specific Romerolagus diazi Information

  • Eyes closed at birth. (J23.10.w4, J469.360.w1)

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Legs, Spine and Tracks

Notes

Specific Romerolagus diazi Information
  • Short legs and feet. (B147, B605.12.w12, B607.w20)
  • Hind foot length: 42 - 55 mm mean 51.3 mm (seven females); 40 and 55 mm (two males); 52 mm (six adults); 53 mm (one adult). (J469.360.w1)
  • Tracks normally show four toes on both the fore and hind feet, but occasionally the print of fice toes is visible for the forefoot. Front feet tracks average 3.0 cm long, 1.5 cm wide; those of the hind feet average 4.0 cm long, 1.5 cm wide. The distance between track groups when running is shorter than in other rabbits and there is always one forefoot striking the ground 10 - 12 cm behind the hind feet. (J469.360.w1)
  • Newborns: Hind foot length 17.0 mm (range 16 - 18 mm) for five individuals. (J469.360.w1)

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Tail

Notes

Specific Romerolagus diazi Information

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Skin / Coat / Pelage

Notes

Specific Romerolagus diazi Information

Adult:

  • Short and dense. (B605.12.w12, J469.360.w1)
    • There is longer fur in a pectoral mane; this is the same colour as the ventral fur. (J469.360.w1)
  • Upperparts: uniformly dark brown. (B147, B607.w20, J23.10.w4)
  • Underparts: dark brownish gray. (B147, B607.w20, , J23.10.w4)
  • "...dorsal and lateral parts dark brown to black." (B605.12.w12)
  • Dorsal and lateral fur "antimony yellow mixed with black." Feet upper distal urfaces light buff with ventral surfaces "mummy brown." The side of the nose and orbital region are light buff, ear base warm buff, "underside and throat are light buff mixed with dark-gull grey of underfur." (J469.360.w1)

Adult Colour variations: --

Newborn / Juvenile:

  • Short, dark brown fur at birth. (J23.10.w4, J469.360.w1)

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Detailed Anatomy Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

Notes

Specific Romerolagus diazi Information

Skeleton

  • "The skull of Romerolagus, like that of Ochotona [Ochotona sp.], has no anterior bony projection above the eye socket, but in most other characters it resembles that of Sylvilagus [Sylvilagus sp.]." (B147)
  • This rabbit has a complete clavicle, which articulates with the sternum. (B607.w20, J469.360.w1)

Female reproductive tract

  • This rabbit has three pairs of mammary glands (pectoral, abdominal and inguinal. (J469.360.w1)
  • When the glands are active, two longitudinal strips, up to 2 cm wide connect the three paire of glands, wit two transverse branches which connect the two anterior pairs of glands. (J469.360.w1)
  • The placenta is discoidal. (J469.360.w1)

Male reproductive tract

  • Testes average 17.5 mm long (range 14.0 - 22.0 mm), 9.7 mm wide (range 7.0 - 13.5 mm) (data from 33 wild adult males). (J469.360.w1)

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Life Stages / Natural Diet / Physiology

Life Stages

Notes

BREEDING SEASON:

Specific Romerolagus diazi Information

  • This species is though to breed year-round. (B147, J469.360.w1)
  • Breeding peaks occur during the rainy summer. (B147, J469.360.w1)
  • Breeds from December to July. (B607.w20)
  • Mexico: reproduction occurs between March and June. (B287)
  • Mexico: Known to breed from December to July, with peak breeding activity occurring between January and April. (B287)
    • Females pregnant between May and June. (B287)
  • Females are thought to mate for the first time at between five and eight months of age, weighing between 403 and 650g. (B287)
  • Males first mate at about 6.5 months of age, weighing approximately 440g. (B287)
  • One male mated first when it weighed 543g. (B287)
  • At Jersey Zoo, a wild-conceived litter was born 18th April (conceived before 25th March when the female was caught) and the female mated again in July. (J23.10.w4)
  • In the first year in captivity at Chapultepec Zoo, Mexico City, females bred all year but with a spring peak. (J23.26.w2)

OESTRUS / OVULATION:

General Information

Specific Romerolagus diazi Information

  • The oestrus cycle is reported to last 13 days. (B147, B287)
  • A post-partum oestrus is thought to occur, since females have been found which were both pregnant and lactating. (J469.360.w1)

GESTATION / PREGNANCY:

General Information

  • The gestation period for rabbits is usually between 27-30 days. (B285.w5b)
  • Under adverse conditions (such as during climatic or social stress), female lagomorphs are able to resorb embryos. (B285.w5a)
  • It is thought that some lagomorph species are able to conceive a second litter even before the last young is born; this is known as superfetation. (B285.w5a)

Specific Romerolagus diazi Information

  • Gestation period: 
    • 38 - 40 days. (B147)
    • 39 - 40 days. (B607.w20)
    • 38 - 40 days at Jersey Zoo: a female was placed with a male twice, on 11th and 13th July (copulation was not observed on the second occasion); young were found on 21st August. (J23.10.w4)
    • Estimated 34 - 48 days. (J511.31.w1) Later revised to 39 - 41 days: 39 days in 35%, 40 days in 50%, 41 days in 15% (J511.34.w1)
    • 40 days at Antwerp Zoo. (J469.360.w1)
    • 38.4 - 38.7 days for one pregnancy, based on copulations on a single day over a period of about one hour and birth time known to within nine hours. (J332.62.w2)

PARTURITION / BIRTH:

General Information

  • Newborn rabbits are born with very little or no fur, and their eyes do not open until 4-10 days after birth. (B285.w5b)
  • Rabbits produce altricial kittens (B285.w5b, B430.w2) which are born into fur-lined nests built either under dense cover or within underground chambers. (B285.w5b)

Specific Romerolagus diazi Information

  • In a zoo: young were born in May. (B287)
  • A recently capture female gave birth on 19th April. She conceived again 11-13 July and gave birth on 20-21 August. (J23.10.w4)
  • There appears to be a spring peak in births in captivity. (B287)
  • Births always took place at night in captive rabbits. (J469.360.w1)

Neonatal / Development:

General Information

  • Young were observed to be covered in brown fur at birth, with their ears laid back and eyes closed. They were seen to jump about 6 cm (2.5 inches) off the floor. (J23.10.w4)
    • Eyes open: 5 - 6 days. (J23.10.w4); 4 - 8 days. (J469.360.w1)
    • Remain in nest to 14 days. (J469.360.w1)
    • Eating solid food: 15 - 16 days. (J23.10.w4)
    • More active in the third week - bouncing, preening, jumping and becoming gradually independent of the nest. (J469.360.w1)
    • Independent: 25 - 30 days. (J23.10.w4)
  • Young of 99.4 g (154 mm long) in the wild were still being suckled, while moving around with the doe. (J469.360.w1)
  • Young are only suckled briefly once every 24 hours. (B285.w5b)
  • Rabbit kittens remain together within their breeding chambers. (B285.w5)

Specific Romerolagus diazi Information

  • Fine dark brown fur, laid-back ears and closed eyes at birth. (J23.10.w4)
  • Fur "Dusky Neutral Grey" on the back, "Antimony Yellow" on the sides, upper region of the head, and extremities, "Light Gull Grey" on the ventral side, with little hair in the inguinal region; the eyes were closed, claws large and umbilicus prominent. In another newborn, there was much less hair present. (J332.62.w2)
  • The young are reared in an underground nest. (B147)
  • The young are independent at 25-30 days. (B147)
  • Weaning mass:
    • Approximately 80 g at 20 days of age. (B287)
    • Female: 80-130 g at 3 weeks. (B287)
    • Male: 95-128 g at 3 weeks. (B287)
  • Solid food between 15 and 16 days of age. (B287)
  • Weaned at about 3 weeks of age. (B287, J511.31.w1)
  • Independent between 25 and 30 days of age. (B287)
  • Young are independent of the doe once they abandon their nest, but may remain together with one another (resting and hiding together) at two months old. (J469.360.w1)

LITTER SIZE:

Specific Romerolagus diazi Information

  • Average litter size: 2.1 young. (B147, J469.360.w1)
  • Maximum two embryos per uterine horn and maximum three embryos found per female. (J469.360.w1)
  • Range: one to four young. (B147)
  • Average litter size is two young. (B607.w20)
  • Averages of between 1.5 and 2.5 young per litter have been recorded. (B287)
  • Two young in each of two litters from one female, one conceived in the wild and the second in captivity. (J23.10.w4)
  • At Chapultepec Zoo, Mexico City, mean litter size was 2.3 (41 young from 18 litters). (J23.26.w2)
  • In two litters, two young. A female shot while near-term contained three young. (J332.62.w2)
  • In Japan, 10 young from four litters from one female. (J511.31.w1)

TIME BETWEEN LITTERS / LITTERS PER YEAR:

General Information

  • The inter-birth interval in lagomorphs is reduced by the phenomenon of induced ovulation, and post-partum oestrus, which allows females to conceive immediately after she has given birth. (B285.w5a)
  • A female can produce up to three or four litters per year. (B430.w2)

Specific Romerolagus diazi Information

  • This species produces between one and five young per year. (B287)
  • One female produced two young on 19 April 1968 (soon after being brought to jersey Zoo and a second litter was born on 21 August 1968. (J23.10.w4)
  • In the first year in captivity at Chapultepec Zoo, Mexico City, females produced a mean of 4.5 litters each. (J23.26.w2)

LACTATION / MILK PRODUCTION: 

General Information

  • Leporids only release milk once in every 24 hour period. (B285.w5b)
  • Leporid milk has a very high fat and protein content, and as such is highly nutritious. Although the lactation period is brief, the milk is pumped into the young at a high speed.(B285.w5b)
  • The lactation period has a duration of between 17 and 23 days. (B285.w5b)

Specific Romerolagus diazi Information

  • The female does not lactate from all her six mammary galnds; a mean of four glands per lactating female are active. (J469.360.w1)
  • Solid food between 15 and 16 days of age. (B287)
  • Weaned at about 3 weeks of age. (B287)
  • Independent between 25 and 30 days of age. (B287)
  • Mexico: lactation occurs between February and December. (B287)

SEXUAL MATURITY:

Specific Romerolagus diazi Information

  • This species reaches maturity at approximately six months of age. (B147)
  • At Chapultepec Zoo, Mexico City, captive born females first mated at eight months old, when they weighed 410 - 650 g. (J23.26.w2)
  • At Chapultepec Zoo, Mexico City, captive born males were observed to have descended testes at about five months old. The youngest a male was seen sexually active was about 6.5 months old (440g). (J23.26.w2)

MALE SEASONAL VARIATION:

Specific Romerolagus diazi Information

  • At Chapultepec Zoo, Mexico City, testes of adult males were descended year-round. (J23.26.w2)
  • Testes remain descended year-round. (J469.360.w1)

LONGEVITY / MORTALITY:

General Information

  • Rabbits and hares in the wild live for less than a year on average; a maximum age of 12 years has been recorded in a couple of species. (B285.w5b)

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Natural Diet

Notes

NATURAL DIET:

General Information

  • Lagomorphs only eat vegetation, mainly grasses and other herbaceous plants. Bark from young trees and small shrub stems may be eaten when food supplies are scarce. (B147, B285.w5c, B430.w2)

Specific Romerolagus diazi Information

  • Zacaton grass. (J23.10.w4)

  • Seems to forage frequently upon the aromatic mint plant (Cunila tritifolium). (B147)

  • Captive individuals of this species were fed high-protein chinchilla pellets, and various fruits, grasses and other vegetable matter. (B147)

  • This species has been reported to eat the following "zacaton" grasses:

    • Festuca amplissima.

    • Stipa ichu.

    • Epicampes sp.

    (B605.12.w12)

  • The Volcano rabbit also feeds on Alchemilla sebaldiaefolia and Museniopsis arguta. (B605.12.w12)

  • "Volcano rabbits select the green and tender young leaves of grasses, biting the base and lower edges of the clump." (B605.12.w12)

  • This species has been observed feeding on the young leaves of spiny herbs including Erynigium and Cyrsium. (B605.12.w12)

QUANTITY EATEN: --

STUDY METHODS:

  • Analysis of fecal pellets. (J23.10.w4)

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Hibernation / Aestivation

Notes

--

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Haematology / Biochemistry

Notes

HAEMATOLOGY: --

BIOCHEMISTRY: --

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Detailed Physiology Notes
(Summary information provided for pertinent species-specific data cross-referenced in WILDPro)

Notes

METABOLISM (TEMPERATURE): --

RESPIRATORY SYSTEM (RESPIRATION): --

CIRCULATORY SYSTEM (PULSE/HEART RATE): --

GASTROINTESTINAL SYSTEM (FAECES AND GUT MOTILITY): 

General Information

  • Lagomorphs have digestive systems which are adapted for processing large quantities of vegetation. (B285.w5a)
  • Lagomorphs are well adapted for obtaining the greatest possible value from their food. They produce two types of fecal material: moist pellets and dry pellets. The moist pellets are expelled and then eaten (a behaviour known as coprophagy (B285.w5a)); this is done with little or no chewing, and as a result the majority of the food passes through the digestive tract twice (this is thought to have the same function as 'chewing the cud' in ruminants). The dry fecal pellets are not eaten. (B147)

Specific Romerolagus diazi Information

  • "The droppings are the typical lagomorph ellipsoid but are very small." (B147)
  • Droppings small and round, easily crumbling to dry dust. (J23.10.w4)
  • Discoidal faecal pellets, swollen centrally, 5 - 9 mm diameter. When fresh, ochraceous, smooth and shiny; once dry, yellowish. (J469.360.w1)
  • Pellets are found in clumps near burrows and throughout runways. (J469.360.w1)

URINARY SYSTEM (URINE): --

CHROMOSOMES: 2n = 48. (J469.360.w1)

MUSCULO-SKELETAL SYSTEM: --

SPECIAL SENSES AND VOCALISATIONS:

General Information

  • All lagomorphs use scent products secreted from special glands. (B285.w5a) These glands are located under the chins and in the groin, and are believed to play a key role in sexual communication, as well as in signalling social status in some gregarious species. (B285.w5b)
  • Whereas pikas tend to be more vocal, rabbits and hares rely strongly on scent rather than sound as a means of communication. (B285.w5b)
  • High-pitched distress squeals are emitted by leporids when captured by a predator, and specific alarm calls are produced in five rabbit species. (B285.w5b, B430.w2)
  • Some rabbit species thump the ground with their hind feet when faced with danger (B285.w5b, B430.w2); this reaction is thought to be a warning to nestlings underground. (B285.w5b)
  • The conspicuous white underside present on the tails of some rabbit species can act as a visual warning to other individuals when fleeing from a predator. These species tend to be found in more open habitats.(B285.w5b)

Specific Romerolagus diazi Information

  • These rabbits often utter high-pitched, penetrating calls; these have been reporte to be heard more often after rain. (J469.360.w1)
  • Two types of vocalisations have been heard: a squeak "like someone rubbing a wet thumb over a balloon" and a short, single high-pitched bark. (J23.10.w4)
  • Five different vocalizations have been described. (J469.360.w1)
  • A sharp call is given when wild volcano rabbits are alarmed. (J469.360.w1)
  • The sharp call is used when this rabbit is startled (also when handled). They also thump their hind legs on the ground, similar to Oryctolagus cuniculus - European rabbit. (J23.10.w4)
  • This species emits pica-like vocalisations. (B607.w20)

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Behaviour

Feeding Behaviour

Notes

General Information
  • Lagomorphs are well adapted for obtaining the greatest possible value from their food. They produce two types of fecal material: moist pellets and dry pellets. The moist pellets are expelled and then eaten; this is done with little or no chewing, and as a result the majority of the food passes through the digestive tract twice (this is thought toe have the same function as 'chewing the cud' in ruminants). The dry fecal pellets are not eaten. (B147)

Specific Romerolagus diazi Information

  • "Volcano rabbits select the green and tender young leaves of grasses, biting the base and lower edges of the clump." (B605.12.w12)
  • Feed on zacaton grasses, also on herbs. Seen feeding on young leaves of spiny herbs; thought to eat outer bark from young alder trees, also seeds of Sycios angulata, an annual vine. In the rainy season, young cultivated oats and maize are eaten. (J469.360.w1)

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Parental Behaviour

Notes

Note: There is very little data specific to this species so the details below are from general leporid information.
  • Male leporids are not generally involved in care of the young. However, if adult females attack young leporids, males will intervene, a behaviour known as 'policing'. (B285.w5b)
  • Even maternal care of the young is not particularly prominent in leporids, hence this reproductive strategy is known as 'absentee parentism'. (B285.w5a)
  • Leporids demonstrate an unusual system of nursing; the young are suckled only briefly (often less than five minutes) just once every 24 hours. (B285.w5b)
  • It is thought that the lack of social contact between the mother and her young is a strategy which diminishes the chances of attracting the attention of predators. (B285.w5b)
  • The entrances to breeding tunnels are carefully re-sealed following each bout of suckling (B285.w5b)

Specific Romerolagus diazi Information

  • In the wild, a small circular chambers with vegetation and some fur was found which was thought to be a nest intended for young. A nest has also been dug out from under a pine root; this was made from pine needles and lined with the rabbit's fur. (J23.10.w4)
  • Nests of wild females are a shallow hole by the base of a clump of zacaton (bunch grass) - the nest is hidden by the leaves of the zacaton. Average 15 cm diameter, 11 cm deep, lined with dry vegetation fragments (pine, alder, herbs and zacaton) and fur from the female - this lines lines and fills most of the nest cavity. Usually the nest entance is covered with plant fragments. (J469.360.w1)
  • A female gave birth in her nest box not long after arriving at Jersey Zoo and was first seen sitting over the kits, having cleaned them. Later, the kits were seen covered in hay while their mother sat by them. With a second litter later in the year, she had constructed a fur-lined nest. (J23.10.w4)
  • Females at Chapultec Zoo, Mexico City gave birth in a fur-lined nest constructed in bundle-grass (zacaton) vegetation. When no such zacaton was available, a female used an indoor den. (J23.26.w2)
  • Interactions between the doe and kits are rarely seen since she is reluctant to approach the nest when observed. However, approach of the doe has occured when the young uttered distress calls while being handled. (J469.360.w1)
  • Young are independent of the mother once they leave the nest. (J469.360.w1)

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Social Behaviour / Territoriality / Predation / Learning

Notes

SOCIAL BEHAVIOUR:

Specific Romerolagus diazi Information

  • Lives in small colonies (J23.10.w4), with observed groups consisting of between five and seven individuals. (B147)
  • Lives in groups of between two and five individuals. (B605.12.w12, B607.w20, J469.360.w1)
  • The social organisation of this species has yet to be studied in the wild. (B605.12.w12)
  • Among captive groups at Chapultec Zoo, Mexico City, kept in semi-natural enclosures, with groups of two males and four females, clear dominance hierarchies developed, with one dominant male (the other being excluded from the activities of the group) and one dominant female in each group. The dominant female chased the other rabbits (including the dominant male, was heavier than the others, and was the only female to breed. When a dominant female dies, another female gained weight and bred. (J23.26.w2)
  • In captivity, females were noted to be clearly aggressive toward both sexes, while males were never observed to initiate aggression toward a female. (B605.12.w12, J469.360.w1)
    • if males were placed together they would chase but not fight. (J469.360.w1)
    • When females and males were introduced at Antwerp Zoo, usually the female would first attack the male, but later they would only chase. (J469.360.w1)
    • A given male would always choose a single female; if she was absent, he would become interested in another female. (J469.360.w1)
  • It has been noted that the dominant individuals within a group were always females, and that aggression between females was both more frequent and violent than aggression between a male and female. (B605.12.w12)

PREDATION:

Specific Romerolagus diazi Information

PREDATOR AVOIDANCE:

General Information

  • Rabbits use dense cover to hide from predators. (B285.w5b)

POPULATION DENSITIES:

Specific Romerolagus diazi Information

  • "Density of animals is possibly high in certain patches of "zacaton" within the core habitats, as reflected by the high density of latrines." (B605.12.w12)

HOME RANGES AND DISTANCES TRAVELLED:

Specific Romerolagus diazi Information

  • Home ranges 0.25 - 3.50 hectares. (B147)

TERRITORIALITY:

General Information

  • The majority of hares and rabbits are non-territorial; some hares occupy home ranges of up to 300 ha (740 acres). ranges of individuals may overlap in favoured feeding grounds. (B285.w5b)

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Sexual Behaviour

Notes

Romerolagus diazi specific information
  • In observed copulations, the male kept pace with the female, directly behind her and sometimes nuzzling her hindquarters; the female turned back towards his flank; both rabbits then circled rapidly for several turns before the male mounted and gave a series of rapid pelvic thrusts. (J469.360.w1)
  • When a male and female were given access to one another, the female approached the male after about 100 minutes. "He then responded in like manner, then pursued her for 5 s. The performance was repeated three times before the buck mounted the doe. During copulation the doe remained motionless, "on all four outstretched legs, with the body well separated from the ground. The male stood on his hind legs with most of his body resting on the female." He maintained his position by grasping the posterior part of the thorax and gave a series of pelvic thrusts for 80 s. At the end of this time one of the rabbits gave a cry like that heard when attacked by a predator and the pair separated; each then liked its own genital area. Later the female repeated her previous behaviour of seeking then fleeing the male. Three further copulations occurred over about the next 45 minutes, after which no further sexual behaviour was seen the animals were separated 20 minutes later. (J332.62.w2)

General information

  • All lagomorphs use scent products secreted from special glands. (B285.w5a) These glands are located under the chins and in the groin, and are believed to play a key role in sexual communication, as well as in signalling social status in some gregarious species. (B285.w5b)

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Activity Patterns, Self-grooming and Navigation

Notes

ACTIVITY PATTERNS:

Specific Romerolagus diazi Information

  • "It seeks the warmth of the sun on cold mornings and after cold, heavy rainstorms." (B147)
  • In good weather, these rabbits may be found playing, foraging, fighting or sleeping above ground. (J23.10.w4)
  • The main activities seen above ground in daytime are "playing, fighting, chasing, foraging, or sleeping among the clumps of "zacaton" grass." (J469.360.w1)
  • These rabbits make extensive use of runways in the cover of bundle-grass. (J182.29.w1)
  • One individual in Antwerp zoo was noted to perch and sleep on a branch 1m above ground level. (J469.360.w1)

SELF-GROOMING: --

CIRCADIAN RHYTHM:

Specific Romerolagus diazi Information

  • Mostly active at night and twilight. (B147)
  • "Mainly active in daytime, sometimes at night." (B607.w20)
  • May be seen during the day, particularly during cloudy weather and the mating season. (B147)
  • Both diurnal and nocturnal. In the wild they have been reported to be particularly active in early morning and in the evening, and generally rested in the middle of the day. (J23.10.w4, J469.360.w1)
  • Large numbers of these rabbits are out of their burrows at 1100 and and 1400 hours. (J469.360.w1)
  • At Chapultepec Zoo, Mexico City, it was noted that daytime activity was much greater in an enclosure with plentiful zacaton (bundle-grass) ground covering vegetation than in another enclosure where the vegetation had not yet grown properly. (J23.26.w2)

SPEED OF MOVEMENT:

General Information

  • The North American leporids are able to escape predators by taking instant flight at high speed. (B430.w2)

Specific Romerolagus diazi Information

  • This species is unusual in that it trots, rather than hops. (B147)
  • Described as "scuttling away" when surprised. (J23.10.w4)

NAVIGATION: --

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Habitat and Range

General Habitat Type

Notes

Specific Romerolagus diazi Information
  • This species is only found in open pine forests in which there is heavy ground cover of zacatón grasses (Epicampes and Festuca). (B147, B605.12.w12)
  • Found in areas of pine forest with rocky substrates. (B605.12.w12)
  • This species is usually found at elevations of between 2,800 and 3,200 m. (B147)
  • Relies upon a pine forest-bunch grass ecosystem. (B147)
  • "Habitat unique "zacatón" (principally Epicampes, Festuca, and Muhlenbergia) grass layer of open pine forest at 2,800-4,000m." (B607.w20)
  • Pine-zacaton habitat. (B605.12.w12)
  • Found between elevations of 2,800 m and 4,250 m. (B605.12.w12)
  • "Most of the areas where the rabbit is found have winter drought and summer rains with a meal annual precipitation of around 1,500mm." (B605.12.w12)
  • Mean temperature in the area where rabbits were found was 9.6o C. The coldest month is January and the hottest May. (B605.12.w12)
  • "The main volcano rabbit habitat is an open forest of Pinus montezumae and Pinus hartwegi up to 25m high, intermixed with other pine species (P.rudis, P.teocote, P.patula and P.pseudostrobus). There is usually a dense ground cover of tall, coarse, clumped "zacaton" grass, mainly Muhlenbergia macroura, Festuca rosei, F.amplissima and Stipa ichu." (B605.12.w12)
  • The following herbs are associated with this species and the zacaton bunch grasses:
    • Penstemon stenophyllum.
    • Geranium potentillaae.
    • Stachys agraria.
    • Lupinus montanus.
    • Senecio salignus.
    • Gnaphalium conoideum.
    • Plantago patagonica.
    • Bidens diversifolia.
    • Alchemilla sebaldiaefolia.
    • Museniopsis arguta.

    (B605.12.w12, J469.360.w1)

  • "The rabbit occurs in a variety of plant communities, from pure stands of pine with an understorey of bunch grasses through formations of dense secondary vegetation composed of alder Alnus firmifolia and Senecio spp." (B605.12.w12)

  • It has been suggested that the scattered distribution of this species within its core habitat may be a result of correlation with the density of "zacaton" cover. (B605.12.w12)

  • Found at 2,800 - 4,250 m elevation, in pine forests with bunch grass understory, and in alder forests with a shru layer and dense zacaton-herb layer. (J469.360.w1)

  • In a study, volcano rabbits were found most in pine-alder forest (which incorporates grassland areas), although they were found also in alder forest, pine-grassland and grassland. Herbaceous cover appeared to be important and they were found more in areas with thicker cover, particularly dense tussock grass, and less modification of habitat. It was considered that their choice of habitat may be a compromise between levels of cover provided by clumped grasses, and amounts of food provided by abundant forbs (and possibly by alder leaves). (J182.29.w1)

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Nests / Burrows / Shelters

Notes

Specific Romerolagus diazi Information
  • "Unlike most rabbits, it maintains a well-defined system of runways through the dense tussocks of grass." (B147)
  • Reported to live in burrows. (B147)
  • Burrows "were generally dug on gently sloping ground facing south." They were "very complicated burrows with many different exits for escape. On two occasions we found, down short side burrows, small circular chambers which contained a small quantity of dried leaves, grass and on one occasion a small quantity of rabbit fur, which we took to be preliminary nest making as it was the beginning of the breeding season." (J23.10.w4)
  • Burrows are generally "...dug on gently sloping ground facing south, are very complicated, with many exits for escape, and apparently contain nests of grass, dried leaves, and rabbit fur." (B147)
  • Burrows may measure up to 5 m in length, and 40 cm deep. (B147)
  • Reported to live in burrows and under rock piles, with an intricate system of surface runways within dense bunchgrass vegetation. (J23.10.w4)
  • Despite reports of burrows, other authors found this species to live mainly on the surface under dense cover of zacatón. (B147)
  • Thought to make use of the abandoned burrows of armadillos, badgers, ground squirrels and pocket gophers. (B147, B605.12.w12)
  • Warrens. (B607.w20)
  • There is little evidence of this species being an active burrower. (B605.12.w12)
  • This species tends to live on the surface, under cover of dense stands of "zacaton". Runways are formed by the movement of the animals. (B605.12.w12)
  • Burrows have an entrance hidden at the base of a zacaton clump; there may be additional escape openings. The oblique openings are about 10.8 cm high and 9.3 cm wide; tunnels are about 10.9 cm high and 11.1 cm wide. Tunnels may be up to 5 m long and up to 40 cm deep; they are not straight but go around rocks and roots; sometimes they bifurcate. Within the burrow the temperature can be 4 °C lower than outside, with the humidity being higher. (J469.360.w1)
  • They may also use abandoned burrows of other species, and refuges such as hollows between rocks. (J469.360.w1)
  • Natal nests:
    • "Females build nests in the wild and in captivity and have been observed to excavate a round cavity in the soil or amidst a "zacaton" clump." (B605.12.w12)
    • Nests of wild females are a shallow hole by the base of a clump of zacaton (bunch grass) - the nest is hidden by the leaves of the zacaton. Average 15 cm diameter, 11 cm deep, lined with dry vegetation fragments (pine, alder, herbs and zacaton) and fur from the female - this lines lines and fills most of the nest cavity. Usually the nest entance is covered with plant fragments. (J469.360.w1)
    • At Chapultec Zoo, Mexico City, it was noted that females gave birth in fur-lined nests in zacaton (bundle-grass) vegetation. A female which gave birth before the bundle-grass had grown properly, used an inside den. (J23.26.w2)
    • At Chapultec Zoo, Mexico City, burrowing behaviour was not generally noted, but was seen once in an enclosure where the bundle-grass (zacaton) had not yet grown properly to form a covering layer of ground vegetation. (J23.26.w2)

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Distribution and Movement (Migration etc.)

Notes

Specific Romerolagus diazi Information
  • Endemic to central Mexico. (B605.12.w12, J469.360.w1)
  • This species is found in the mountains southeast of Mexico City. (B51)
  • "...restricted to a small mountainous region of central Mexico, mainly in the Distrito Federal and the states of Mexico, Morelos, and Puebla." (B147)
  • This species is thought to have the most limited range of any mammal in Mexico. (B147)
  • "It occurs on the middle slopes of the volcanoes Popocatepetl and Ixtacihuatl and on adjoining ridges bordering the Valley of Mexico on the east and south." (B147)
  • "Distrito Federal, Mexico, and W Puebla (Mexico), in three discontinuous areas on the slopes of Volcán Pelado, Tlaloc, Popocatépetl, and Ixtaccíhuatl." (B607.w20)
  • "Restricted to two volcanic sierras (Ajusco and Ixtaccihuatl-Popocatepetl ranges) close to Mexico City." (B607.w20)
  • This species has a restricted distribution, being found only in three discontinuous areas. This core habitat covers an area of approximately 280 km2, and is found in central Mexico across four volcanoes:
    • Approximately 146 km2 of this area is found around Popocatepetl and Iztaccihuatl.
    • Approximately 48 km2 of this area is found around Pelado.
    • Approximately 86 km2 of this area is found around Tlaloc.

    (B605.12.w12)

  • Found on the slopes of the following four volcanoes within the Tranverse Neovolcanic Belt (TNB):
    • Popocatepetl (Sierra Nevada).
    • Iztaccihuatl (Sierra Nevada).
    • El Pelado (Sierra Chichinautzin).
    • Volcan Tlaloc (Sierra Chichinautzin).

    (B605.12.w12)

  • It is previously though to have been found in other areas including the eastern slopes of Iztaccihuatl and the Nevada de Toluca. (B605.12.w12)

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Conservation

Species variation

Notes

Specific Romerolagus diazi Information
  • This species is considered by many to be the most primitive of the living leporids. (B605.12.w12)

Currently recognised subspecies include:

  • Romerolagus diazi diazi: includes Romerolagus diazi nelsoni. (B607.w20)

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Conservation Status

Notes

Specific Romerolagus diazi Information

WILD POPULATION - IMPORTANCE:

  • In 1969 the population was estimated to be between 1,000 and 1,200 individuals. A later survey in the late 1980s found this to be a severe underestimate, with 6,500 individuals found around Volcano El Pelado alone. (B147)
  • "No reliable estimates." (B605.12.w12)
  • "Recent studies...indicate that this rabbit has disappeared from substantial parts of its original range and now is restricted primarily to four major discontinuous areas of suitable habitat, each centering on a volcano, which are fragmented further into 16 patches, with a total area of approximately 386 sq km." [1999](B147)

GENERAL LEGISLATION:

  • USDI - Endangered. (B147)
  • U.S. Endangered Species Act (ESA) - Endangered. (B607.w20)
  • Protected by Mexican law. (B147)
  • "Although the hunting of the volcano rabbit is now illegal, this legislation is not enforced and the species is still hunted." (B605.12.w12)
  • The areas in which this species is found are protected (Izta-Popo and Zoquiapan National Parks). (B605.12.w12)

CITES LISTING:

RED-DATA LIST STATUS:

  • IUCN - Endangered. (W2.Apr08.w73)

THREATS:

  • Hunting. (B147, B605.12.w12)
  • It was noted [1968] that although officially protected, lack of effective patrolling meant that indiscriminate shooting occurred. (J23.10.w4)
  • Habitat loss due to overgrazing, conversion to agricultural land, fire and encroaching development. (B147, B605.12.w12)
  • Habitat loss also occurs due to over-exploitation of timber and the cutting down of "zacaton" grasses for the manufacture of thatch and brush. (B605.12.w12)
  • "Building developments in the Izta-Popo National Park pose a threat to surrounding habitat." (B605.12.w12)

PEST STATUS / PEST POPULATIONS: --

CAPTIVE POPULATIONS:

  • The following organisations have kept Volcano rabbits in captivity:
    • Faculty of Science, U.N.A.M.
    • Antwerp Zoo.
    • Central Institute for Experimental Animals, Japan.
    • Jersey Wildlife Preservation Trust.
    • Chapultepec Zoo, Mexico City.

    (B605.12.w12)

  • Only three of these organisations currently hold colonies:
    • Jersey.
    • Chapultepec.
    • Central Institute for Experimental Animals, Japan.

    (B605.12.w12)

  • "The Chapultepec colony, where the animals are grouped in outdoor enclosures planted with clumps of "zacaton" grasses, bred particularly well for the first couple of years...but infant mortality has been very high." (B605.12.w12)
  • The captive breeding efforts at Jersey and Antwerp Zoo were not as successful. The captive breeding programme for Volcano rabbits at Antwerp Zoo has recently been terminated. (B605.12.w12)
  • "In an attempt to emulate the Chapultepec accomplishment, similarly planted enclosures have been set up at Jersey Wildlife Preservation Trust." (B605.12.w12)*

TRADE AND USE:

  • Extensively hunted for target practice. (B147)
  • Used as dog food. (B147)

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