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Enrichment Committee
The Ursidae, or bear family, is comprised of animals that normally inhabit large home ranges and have great strength proportionate to body size. Successful captive management must address the bears’ innate motivation for movement or travel, as well as containment issues relative to their potential to destroy their enclosures.
Natural History
The world’s eight bear species are distributed throughout North and South
America, Europe and Asia. Spectacled bears inhabit the Andes Mountains of
South America. The giant panda is restricted to central Chinese provinces.
Malayan sun bears are found in Southeast Asia and sloth bears in central Asia,
whereas Asiatic black bears are widely distributed throughout the entire Asian
continent. Polar bears range across the arctic coasts of North America and
Eurasia. American black bears live throughout the North American continent;
however, the widest distribution in any bear species is seen in the brown
bear, whose habitat includes North America, Eurasia and northwestern Africa.
Species with wide geographical ranges have resulted in several subspecies,
many based on size and pelage differences.
Bears live in habitats that range from arctic ice floes and tropical forests at sea level to grasslands and alpine forests. From the terrestrial and aquatic polar bear to the highly arboreal sun bear, they utilize various parts of their habitats, depending on their physical adaptations.
Ursid diets are as varied as their habitats. Whereas the American black bear is omnivorous, others, such as the giant panda, are folivorous, or carnivorous, such as the polar bear. Bears are intelligent and opportunistic. They quickly learn where their food comes from, and in captivity, when it is delivered, becoming predictable in their behaviors.
In general, bears are well adapted to their environments. They have adequate eyesight and hearing to negotiate their natural environment, accompanied by an excellent sense of smell. Many are excellent climbers, whereas others travel great distances in search of food or mates. Several species that tend to be solitary, such as the brown bear, will congregate during major feeding events, such as the beaching of a whale carcass or the salmon run. All species are heavily built with powerful limbs and can be dangerous if provoked. They possess strong claws that are adapted for tearing and digging and, for some, climbing. Random and variable enrichment can provide novelty and stimulation that mirror activity and changes in the animals’ natural world.
The management of captive bears can be challenging. Stereotypic behaviors, such as pacing, pattern swimming, food solicitation from the public, and repetitive behaviors can be common in the captive environment. The nocturnal or crepuscular nature of some species may cause animals to be inactive or hidden during much of the public viewing period. Promoting normal wild behavior through the provision of suitable species-specific enrichment can lead to improved mental and physical health. Well adjusted animals should exhibit behaviors that reflect reduced stress levels and are appropriate for public display.
Exhibit Enrichment
Ursids are relatively large and destructive animals requiring appropriately
sized enclosure furniture. Depending on the naturalistic state of the exhibit,
it may be beneficial to install sleeves or other such structures to provide
attachment points or stability to allow for large or heavy items.
Because many bears are strong diggers, enclosure mesh must be heavy gauge, but also embedded deep in the ground to prevent the bears from opportunistic tunneling. Vertical climbing opportunities are desirable for many species, and juveniles of normally terrestrial species may also benefit from climbing structures. However, large props can break, causing injury to animals, and providing potential escape routes. Therefore, climbing structures should be monitored for structural integrity and the potential of being used by the animals for escapes if broken or compromised.
Off-exhibit areas should offer suitable climbing, sleeping or denning opportunities, especially if the animals will spend evenings or winters in these areas. Bears can benefit from continuous indoor and outdoor access options. Many facilities provide considerable artificial-looking enrichment in holding areas, while maintaining naturalistic public viewing exhibits. Although the type of enrichment may differ, it must be stressed that all bear areas should contain appropriate and sufficient enrichment choices. For example, shelter, sun, shade, heated rocks, cooled areas or water features either on or off exhibit provide options that allow animals to regulate their own activity levels, temperature and visibility to the public.
Built-in visual barriers can provide a retreat for the animals from the public or cage mates. These can include rock structures, uneven terrain, tree plantings, logs and brush piles. Dens can provide escape from the elements as well as natural cubbing areas or shelter for species exhibiting winter lethargy.
Live trees and bushes can provide visual barriers, as well as shade and climbing opportunities. Certain trees may need collars, electric fencing or other barriers to prevent damage from bears clawing, scratching and rubbing on the trunks. Trees in proximity to exhibit barriers, may provide escape opportunities and should be trimmed to ensure that the bears cannot walk or jump out of the enclosure or use fallen limbs to facilitate escape. Similarly, strong animals may be able to knock down or rearrange furniture against perimeter fencing, which can lead to escapes from the enclosure.
Various substrates provide considerable interest for many ursids. Mulch, sand, gravel, soil, grass, leaves, hay, and moss can encourage natural exploratory behaviors. Ingestion is not normally a problem with these items, but animals should be monitored when first offered access to new substrates. A variety of substrates can provide bears with options for foraging and digging, as well as nest building.
Water features are desirable for many bear species and often encourage species-typical behavior. Shallow pools and streams provide a source of drinking water and can be stocked with live fish or floating objects, while deeper pools provide swimming and loafing options.
Dietary Enrichment
Bears are generally omnivorous, but differ in their levels of carnivory, folivory
or insectivory. The highly carnivorous polar bear relishes certain types of
vegetable material and the mostly folivorous giant panda will opportunistically
eat meat. These tendencies allow for a great deal of variety in food enrichment,
including timing, delivery and content. For example, artificial termite mounds
and distance suction feeders might be provided to highlight specialized insect
feeding adaptations, as seen in sloth bears.
Carcass feeding encourages the normal behavior of animals at a kill. The entire carcass can be eaten, so a variety of nutrients are obtained and natural jaw action, tooth wear and digestive processes occur as well. In a social group, the pecking order, loosely based on size and reproductive condition, will also be observed, where subordinate animals may have to wait their turns to eat. Encouraging such natural behavior, however, is not without risks. These may include injury from other members of the social group, tooth breakage, or impaction and blockage from ingested bones.
Social Enrichment
For maximum activity benefit to the animals, as well as for public interest,
zoos often exhibit bears in pairs or groups, although many species in the
wild are solitary for much of the year. Housing animals in social groups can
be an effective form of enrichment, but staff should regularly monitor behavior,
food intake, and use of enrichment and exhibit furniture to ensure the needs
of all animals in the enclosure are being met. Subordinates often need places
in which to escape unwanted attention without becoming trapped. Food should
be provided in more than one location to ensure that all animals are able
to access appropriate quantities. Multiple food stations, multiple daily feedings,
and scattered foraging opportunities are all methods to alleviate this issue.
Mother and cub groupings may also be successful until animals reach sexual
maturity or become aggressive. Breeding and cub rearing opportunities can
be valuable enrichment, in that not only are both mother and cub mentally
stimulated, but this also allows both to perform species-appropriate behavior
while providing cubs with an environment in which to develop normal social
skills.
Seasonality
Several bear species exhibit winter lethargy and may den up during certain
parts of the year or in response to cold, inclement weather. Keepers need
to be aware of this seasonality, as well as normal daily activity patterns
when providing bears with enrichment opportunities. The animals may need ‘down
time’ and thus should not be expected to maintain certain activity levels
at all times of the day or year. Natural dietary fluctuations may correspond
to seasonal behavior, requiring a shift in the type and/or quantity of food
offered.
Training as Enrichment
Training programs provide animal stimulation and can be valuable management
tools. Many bears can be trained to perform simple behaviors, such as body
part presentations, or mouth open for physical examination. Training for co-operative
shifting can facilitate safe and reliable keeper access to exhibits for placement
of enrichment as well as during emergency situations. Crate training should
be considered where appropriate to minimize stress and improve keeper and
animal safety during transport. To facilitate transports, holding areas should
be designed with training or interaction areas that are safe for both staff
and animals. Removable panels or attachment sites for crates should be considered.
Safety Considerations and Documentation
Safety should be a primary consideration when introducing new enrichment.
Input from supervisory staff is important and animals should always be closely
monitored when new items are offered. Horticulturists should be consulted
regarding browse or plant toxicity. Donated leaves, limbs or trees should
be checked for prior pesticide application. Christmas trees should be free
of tinsel, fire retardant, fake snow, greening agents, etc.
Because individual animal responses to the same enrichment can be very different, careful observation and documentation are necessary. A written assessment of each enrichment event is desirable. This provides a permanent record that can be valuable in reducing future problems, such as the potential for ingestion, entanglement, or aggression from or toward cagemates. In addition, documentation and evaluation of enrichment can lead to additional applications for medication delivery and other methods for improving animal management. One animal may wrestle with an item for extended periods, while another might destroy it immediately and leave it, and yet another might try to ingest it. Documentation of individual differences will allow keepers to tailor enrichment to maximize its benefits. The assessment may be added to a compendium of ideas that may spark interest from other staff, for other species, or at least reduce the constant “reinvention of the wheel”.
Conclusion
Captive bear management remains a challenge. Bear are recognized by and popular
with zoo visitors, giving them a high profile. Increasing public concerns
regarding animal welfare can often be addressed or resolved through the provision
of and interpretation of enrichment. Conservation of wild populations and
their habitat and the importance of well adjusted animals for reproductive
success, are messages that can stimulate public appreciation for these magnificent
animals.
A successful bear enrichment program will provide a balance between risk factors associated with enrichment and maintaining species-appropriate behaviors and that promote physical and psychological well being for captive bears. Incorporation of enrichment as part of the keepers’ daily husbandry routines can helps to ensure the health of the animals, and therefore the educational value of the exhibit, and create a positive perception among the visiting public.
Exhibit Enrichment
Dietary Enrichment
Social Enrichment
Novel Enrichment
Safety Considerations
Bear enrichment guidelines compiled by Laurie McGivern, Bird Supervisor, Dallas Zoo, AAZK National Enrichment Committee.
Reviewed by:
Else M.B. Poulsen, Head Zookeeper, Arctic Ring of Life/Bears, Detroit Zoological
Institute
Jay Pratte, Senior Mammal Keeper, Dallas Zoo
Alicia Shelley, Keeper, North America Region, Columbus Zoo and Aquarium
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