Hand-rearing Brown Bears  (Disease Investigation & Management - Treatment and Care)

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Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords Hand-rearing of Ursus arctos - Brown bears
Description Hand-rearing of orphaned or rejected bear cubs.

Note: Care must be taken with orphaned wild bear cubs, which are to be released back to the wild, not to imprint the cubs on humans or let them become habituated to humans or domestic animals such as dogs. (B432.w6)

  • Staff looking after cubs for release should not speak while with the cubs, and should wear a dark mask and dark gloves. (B432.w6)
  • While giving access from an indoor den to the outside, staff should keep out of sight to avoid the bears developing a "following response" to humans. (B432.w6)
Initial Care
  • Preventative antibiotic treatment should be considered for cubs which have not received colostrum (i.e. cubs hand-reared from just after birth). (J23.9.w4)
  • Cubs at one zoo were given two teaspoons of Lactobacillus acidophilus culture every 12 hours for two days, then were given ampicillin orally for five days. (J23.13.w15)
  • Consider giving subcutaneous and possibly oral serum from an adult animal of the same species, preferably one at the same location.
    • In domestic cat kittens, parenteral administration of 150 mL serum per kilogramme bodyweight was found to produce normal serum IgG concentrations. (J4.219.w6)
  • Also see information in:
General Care (including warmth and hygiene)
  • The box needs to be lined with soft material to prevent injuries to the nose. (P85.1.w8)
  • Cubs must be kept warm and dry. (B288.w11)
  • Cubs were kept in an incubator set at 26.7 C (80 F) for the first seven weeks, reduced in the eighth week to 23.9 C (75 F); the cubs left the incubator at nine weeks. (J23.9.w3)
  • Cubs were kept in a box warmed with an electric heated pad to give a temperature of 29 - 30 C (84 - 86 F) for the first three weeks, reducing after that to 27.5 C (81 F) and by six weeks they were maintained at room temperature. . (J23.9.w4)
    • By six weeks, in a playpen with a soft mattress and cardboard sides. (J23.9.w4)
    • By eight weeks, cubs preferred to be on a cool tile floor rather than the playpen mattress. (J23.9.w4)
  • Cubs were kept in an incubator at 32.2 C for the first two weeks, reducing in the third week to 29.4 C. (J23.13.w15)
  • Cubs have been kept in a wooden box, insulated and heated by a hot water bottle, with the box kept at 37-38 C for the first 25-30 days. After this time, the hot water bottle was moved to one side of the box, giving the cubs choice about where to lie for thermal comfort. (P85.1.w8)
  • External warmth is required to 1.5 months of age. (B432.w6)
  • Young cubs need to have their muzzles wiped after feeding. (B432.w6)
  • Cubs are kept in a heated house without any humans living in it to three months of age, then in a wooden hut in an open-air, forested enclosure. (B432.w6, W159.Apr06.w1)
  • To minimise human interaction:
    • Dark, cotton gloves are worn when it is necessary to handle cubs, to avoid direct contact with humans. (B432.w6, W159.Apr06.w1)
    • Personnel do not talk while working with the cubs. (B432.w6, W159.Apr06.w1)
    • Faces are covered with dark masks while working with the cubs. (B432.w6)
    • These precautions are intended to minimise the possibility of cubs associating food with any strong, distinct external stimulus. (B432.w6)
Milk Replacer
  • A high fat, low carbohydrate milk replacer (24% fat, 12% protein, almost zero carbohydrates, 38.0% solids) has been recommended. (J54.12.w1)
  • Esbilac. In the first three weeks, powder mixed one part Esbilac to three parts water, with added multivitamins (one drop per day in week one, two drops in week two etc.). From the fourth week, mixed one part Esbilac to two parts water. (J23.9.w3)
    • After 12 weeks the cubs were gradually switched from Esbilac to canned evaporated milk. (J23.9.w3)
  • Esbilac at one part Esbilac to three parts water for the first two weeks, then one part to two parts water to six weeks, then one part to 1.5 parts water. (J23.9.w4)
    • Vitamins added (paediatric multivitamin). (J23.9.w4)
  • A cat milk replacer, KMR, has been used, at varying concentrations from 4:1 to 2:1. (J23.13.w15)
    • Multivitamins were added from day 14 and iron dextran was given on day 25. (J23.13.w15)
  • A mixture of cows milk with cream (fat 6%), 15 g, plus 1 g Mammysan milk powder (26% fat, 50% lactose, 15% protein, 6% milk-salt) and 1 g honey. (J23.4.w1)
  • Ursus arctos - Brown bear cubs can be reared on whole cow's milk from a nursing bottle. (B288.w11)

  • The mixture used by the Pazhetnovs: three litres fresh milk, one litre water, 200 mL semolina, two large spoons dried milk, two tablespoons sugar and a little salt. (D270.VI.w6)

    • As the cubs get older, add cooked barley (made one part barley to five parts water). (D270.VI.w6)

    • Once feeding from a bowl has started, give the formula in the morning, and two additional feeds of the formula with seven eggs, two teaspoons multi-vitamins, seven tablespoons vegetable oil and cooked barley added. (D270.VI.w6)

  • A Kodiak bear (Ursus arctos - Brown bear) cub was fed 15 g whole milk enriched with butter fat to 6% fat, heated to 28 C (82 F) every three hours, with additions of small amounts of honey and "Mammyan", a prepared food. From 90 days vitamins were added in the form of four drops of cod liver oil every three days. (B288.w11)

  • Cubs were reared on a mixture consisting of 500 mL milk, one egg yolk, 1 g glucose and 1 g salt. From 20 days 1 drop of a vitamin ADE mixture (vitamin A 100 mg, vitamin D 10,0000 IE, vitamin E 70 mg) was added. (P85.1.w8)

  • A standard rubber infant nipple with only a slightly enlarged hole. (J23.9.w3)
    • Nipples with a cross-cut hole produced too fast a milk flow for the cubs. (J23.9.w3)
  • An "Evenflo" feeding bottle and a premature baby nipple with the hole not enlarged was used. (J23.9.w4)
    • Keeping the hole small was deliberate to make the cubs work for the milk and reduce the risk of formula being inhaled. (J23.9.w4)
    • For a cub which suckled at fingers but not at the nipple, an infant pacifier (dummy), which was more finger-shaped was modified to make a nipple which was accepted better by this cub. (J23.9.w4)
  • A bottle with a plastic nipple. (B432.w6)
  • Bottle and nipple. (W159.Apr06.w1)

Feeding Frequency
The following schedules have been used:
  • 1) Weeks 1-2 nine feeds per day: every 2.5 hours during the day (0600 - 2330) plus at 0300. (J23.9.w3); Weeks 3-8 eight feeds per day: 0600 - 2330 every 2.5 hours. (J23.9.w3); Weeks 9-12 three feeds daily: 0800,1200, 1600. (J23.9.w3)
  • 2) Initially every two to three hours, including at night on demand (cubs crying), reducing after two weeks to every three to four hours (seven feeds per day), with night feeds given until six weeks of age. (J23.9.w4)
  • 3) Feeding seven times daily, reduced after 30 days to six times daily. (J23.13.w15)
  • 4) For first 23 days, eight times daily. (J23.4.w1)
  • 5) For the first ten days, six times daily, then decreasing to five time daily to 20 days, four times daily to 90 days, and three times daily from 90 days. (P85.1.w8)
  • 6) Fed five times daily. (W159.Apr06.w1)
Feeding Technique
  • Keep the cub on its stomach, body tilted up at about a 45 degree angle. Brace the cub's head and shoulders with one hand; with the other hand hold the bottle (using the thumb and forefinger), and with the rest of the hand, brace the bear's chin. (J23.9.w4)
    • Do not lie a bear cub on its back to feed. (J23.9.w4)
    • Bear cubs must be fed lying on their front with the head slightly elevated holding the nipple of the bottle. A bear cub fed lying on its back may inhale milk and this may result in aspiration pneumonia (Aspiration Pneumonia in Birds, Elephants and Bears). (B123.19.w19)
  • It may be necessary to hold the head and bottle firmly with older cubs to avoid the nipple becoming dislodged by the cub struggling. (J23.9.w3)

The following quantities have been fed:

  • Cubs were fed as much as they wanted at each feed. (J23.9.w4)
  • Five hand-reared European brown bear cubs at about 75 days of age consumed 11.1% body mass (707 g formula) per day. (J54.12.w1)
  • For first 23 days, 15 g of milk mixture per feed (eight daily feeds); by 49 days 600 gm in 24 hours; by 90 days 725 g per 24 hours and by 92 days, 1.08 kg in 24 hours. (J23.4.w1)
  • Cubs were fed as much as they would take at each feed: in the first ten days, 15-200 mL/day; days 10-20, 300-330 mL/day; days 20-30 380-400 mL/day; days 30-40 500-560 mL/day; days 40-50, 600-790 mL/day; days 50-60, 680-730 mL/day; days 60-70, 710-1270 mL/day; days 70-80, 850-1630 mL/day; days 80-90, 1,300-2,050 mL/day; days 90-100, 1,350-2,400 mL/day. (P85.1.w8)
  • Cubs need assistance to urinate and defecate, several times daily. (J23.9.w3)
  • The belly must be massaged to stimulate urination and defecation. (B432.w6)
  • Defecation stimulated by massaging the anal region immediately before each feed, until the cubs were able to walk. (J23.9.w4)
  • Stimulation of urination and defecation was carried out by massage of the belly by hand, and the anal area using a cotton wad; defecation without this stimulation was first noticed at 45 days of age. (P85.1.w8)
  • Massage after every feed. (W159.Apr06.w1)
  • Young cubs need to have their muzzles wiped after feeding. (B432.w6)
  • [No species-specific information available]
  • It is generally recommended that animals should be weighed daily at least in the initial stages of hand-rearing, to monitor progress and check that food intake is sufficient. (V.w5)
The following have been used:
  • Dry pre-cooked baby cereal was first added to the formula at the start of the 11th week. In the 12th week, pureed apples and bananas (one teaspoon per six ounces formula) were added, also ground dog chow, one tablespoon added to the milk. (J23.9.w3)
    • Food also was provided in shallow bowls from the 11th week. (J23.9.w3)
  • First solid foods added to milk at 70 days (crushed biscuits and small pieces bread). At 105 days, gruel with egg yolk and honey, and Maizena four mixed with milk. By 120 days ground carrot, chopped lettuce, biscuits in milk, small pieces of herring, scraped meat, dates, banana. (J23.4.w1)
  • Cubs given access to the outside start to eat grass at about four months. At this age some high-energy food should be given twice daily, but only a small amount so they are encouraged to forage for natural foods. (B432.w6)
    • Foraging behaviour should be well developed by five months and only a small additional evening feed is required. (B432.w6)
  • A Kodiak bear (Ursus arctos - Brown bear) cub started drinking milk from a dish at 70 days and solid foods were added gradually. (B288.w11)
  • In Croatia, five cubs were weaned gradually, starting after they were 107 days old. (P85.1.w9)
  • See: Release of Hand-reared Brown Bears (Techniques) 
  • Critics of hand-rearing for release suggest that hand-reared bears or those raised in captivity can not be released, because they have not been mother-trained to find food and dens and to avoid other bears, and are likely either to starve or to become problem bears eating human-related food sources; (P71.1995.w10, B432.w3)
  • However, other authorities suggest that hand-reared cubs, once released, quickly adapt to their natural habitat. (P71.1995.w16)
    • Accumulated data suggests many hand-reared bear releases can be successful. (D270.IX.w9)
    • A survey found that of 576 released bears (various species) from eight facilities, less than 2% were known to be involved in nuisance situations in the year following release. (D270.IX.w9)
    • Releasing hand-reared brown bears is more likely to result in the creation of problem bears than is the case with other bear species. Hand-reared bears should be released only if this can be carried out in a vast area without people. (V.w101)
Appropriate Use (?)
  • For cubs orphaned before they reach the age of self-sufficiency.
    • Self-sufficiency at seven months was documented for a brown bear cub in Alaska. (J40.37.w2)
    • Brown bear cubs in Austria which lost their mother in September survived the following winter. (P85.1.w9)
    • Cubs in Croatia were presented for hand-rearing at the estimated ages of 33, 40 and 89 days old. It has been suggested that cubs orphaned later than mid-June of their first year should not be taken into captivity at all, and that those orphaned after leaving the den should be artificially fed to no later than mid-June before release, taking care to minimise bottle feeding and taming, while younger cubs should not be reared unless they are to be placed in captivity. (P85.1.w9)
  • In Russia, cubs are orphaned at just a few weeks old when females are shot in winter den hunts in January to March. (B432.w6, W159.Apr06.w1)
  • Hand-rearing for later release is also an option when a female with cubs has become a nuisance bear and has to be euthanased, avoiding the need to euthanase the whole family group. (D270.IX.w9)
Options available for orphaned wild-born bear cubs include:
  • Leaving cubs in the wild. (D270.I.w1)
    • Bear cubs have a chance of surviving alone from as young as 5-7 months, although survival is higher for cubs which are older and larger. (D270.I.w1)
    • Young cubs without their mother are more vulnerable than are older cubs to predation. (D270.I.w1)
  • Placing cubs into permanent captive facilities. (D270.I.w1)
    • Bears are long-lived and such places are limited. (D270.I.w1)
    • For many people, keeping wild-born bears captive is not desirable. (D270.I.w1)
    • Individuals put into permanent captivity are lost to the wild population. (D270.I.w1)
    • This may be necessary for cubs which are too human-orientated and become nuisance bears after release, or are judged likely to be problem bears if released. (J417.20.w1)
  • Hand-rearing for release.
    • This requires careful rehabilitation in appropriate facilities with experienced personnel. (D270.I.w1, J417.20.w1)
    • Survival rates of such cubs after release can be similar to that of wild cubs. (D270.I.w1)
    • Hand-reared cubs, following appropriate rehabilitation methods, can function behaviourally as wild bears. (D270.I.w1)
    • Costs of rearing and rehabilitation are substantial. (D270.I.w1)
    • There is a potential disease risk to the wild population unless care is taken to ensure that released bears are free of diseases and parasites. (D270.I.w1)
    • It is important to ensure that release takes place into suitable habitat with a bear population of an appropriate status (indicated by age structure) and similar genotype to the bear being released. (D270.I.w1)
    • In small, threatened or endangered populations, every cub successfully reared and released may make a difference to the chance of the population surviving. Lessons learned from rehabilitation in non-threatened populations increases the chance of success if it is required in threatened populations. (D252.w4)
    • There are concerns that released bears could become problem bears and might be dangerous.
      • Note: "there are no reports of released bears injuring or killing a person." (D270.I.w1)
      • It has been disputed whether habituated bears are particularly likely to become nuisance animals or aggressive towards people. Initial analysis of a few hundred rehabilitated bears "indicate that only a tiny fraction of bears hand-reared from infancy engaged in nuisance behaviour once independent; few of these were ever aggressive towards people." (N20.12.w4)
    • Frequent contact between cub and caretaker is required in young cubs being bottle-fed, and bottle-fed cubs may continue to show dependence on their caretaker for a period after weaning. However, over time they become more independent and, particularly if other cubs are present to interact with, show less interest in their caretakers. Independence increases as cubs reach the age of normal family break-up in the wild. (D270.VII.w7)
  • Euthanasia.
    • This is an inexpensive option, and humane. (D270.I.w1)
    • This option eliminates any disease risks to the bear or any population it is released into, and avoids any genetic issues. (D270.I.w1)
    • This option is viewed negatively by many people, and may generate negative publicity for a government department in charge of managing and protecting bear populations if used as the default option for orphaned bears. (D270.I.w1)
    • This is an appropriate option for individuals with severe disabilities. (P62.13.w2)
  • Note: bear cubs are individuals and have individual personalities; suitability for release may have to be assessed at the time for release. (D270.I.w1)
  • Avoidance behaviours develop gradually when the cubs are two to five months of age. During this time they should be cared for by only one human, so that while this human's odour is recognised, the odour of other humans causes an appropriate fear response. (B432.w6)
  • Orphaned cubs form bonds with one another based on olfactory and auditory signals. (B432.w6)
  • Orphaned cubs raised in a semi-natural environment developed behaviours as follows: (B432.w6)
    • Foraging: 3.0 - 4.5 months. (B432.w6)
    • Predatory behaviour on small vertebrates:- 6 - 7.5 months. (B432.w6)
    • Avoidance behaviour: first emergence of fear reaction at 4.5 - 5 months; basic development of fear reaction 5 - 6.5 months - cubs become very cautious and immediately run from anything unusual. (B432.w6)
      • Full development of avoidance reaction to humans at this stage depends on isolation from exposure to multiple humans/human odours during early development. (B432.w6)
    • Den construction: 9 - 9.5 months. (B432.w6)
Complications/ Limitations / Risk
  • Cubs may root frantically with their noses in the first two weeks and can rub the skin off their noses (to the point of bleeding) doing this. (J23.9.w3, J23.9.w4)
  • Umbilical hernias, closing spontaneously after eight weeks, have been reported. (J23.9.w3)
  • Navel ill may be a problem, particularly in cubs which have not received colostrum. (J23.9.w3)
  • Cubs which have not received colostrum may be more susceptible to gastro-enteritis. (J23.9.w4)
Equipment / Chemicals required and Suppliers
  • Bottle and nipple. (W159.Apr06.w1)

Expertise level / Ease of Use
  • Rearing bear cubs is time-intensive and requires dedication and experience.
Cost/ Availability
  • Hand-rearing of young bear cubs requires a considerable time investment.
Legal and Ethical Considerations
  • Zoo-born bear cubs should not be hand-reared as a matter of routine. Failure of females to rear cubs usually occurs due to disturbance; every effort should be made to avoid the female being disturbed.
  • Orphaned/abandoned wild-born bear cubs should not be taken for hand-rearing if they are of an age where they are likely to survive alone.
  • Hand-rearing should not be started unless the carer is prepared to give the time and effort required for rearing to release, or to ensure that appropriate care will be continued through to release. 
  • Consider whether hand-rearing is the best option for the individual compared with leaving it in the wild. 
  • Consider whether euthanasia is a more humane/kinder option for the individual than attempting hand-rearing. 
  • If wild-born cubs are hand-reared, every effort should be made to rear them with conspecifics, and to ensure that the cubs are maintained suitable for release, preferably not habituated to humans, dogs etc. 
Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee --
References B123.19.w19, B288.w11, B432.w6, D270.I.w1, D270.VII.w7, D270.IX.w9, P71.1995.w16, P85.1.w8, P85.1.w9, J23.4.w1, J23.9.w3, J23.9.w4, J23.13.w15, J40.37.w2, W159.Apr06.w1

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