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Himalayan black bear (Selenarctos thibetanus)

R.J.P. O'Grady, G. Law, H. Boyle, A. MacDonald & J. Johnstone

Early in 1995 the Glasgow Zoological Society was approached by officials of Dumbarton District Council for advice on a local wildlife park, the Cameron Loch Lomond Wildlife Park. Although the park was no longer open to the public, the problem of the disposal of stock remained. Earlier, escapes of bears in the collection had prejudiced public safety and the 1981 Zoo Licensing Act had placed the responsibility for zoos on local authorities.

With the assistance of the National Federation of Zoological Gardens of Great Britain and Ireland, the majority of bears, Brown bears Ursus arctos and Black bears Ursus (Euarctos) americanus, were moved to the Windsor Safari Park but it proved impossible find a home for a group of 2.4 Himalayan black bears Selenarctos thibetanus.

The owners of the park, the Alloa Brewery Company Limited, and Clive Hollands, Director of the St Andrew Animal Fund repeatedly approached the Society to house the bears at Glasgow but because of our experience with Polar bears Thalarctos maritimus (Law et al., 1986), we were unwilling to proceed unless all modern welfare requirements could be satisfied. The Society finally agreed to accept responsibility after agreeing a written statement of policy and preparing detailed financial costings. The Alloa Brewery Company offered 30,000 to sponsor the project and as much of the original fencing from the bear park as we required.

SITE AND PERIMETER FENCING

Although, in some respects, management of the bears at Loch Lomond had not accorded with modern zoo practice, there were lessons to be learned and in the designing of the new exhibit careful attention was paid to the bears' behaviour patterns. For example, none of the bears had liked the small, half-buried concrete houses, which were damp, and in which the smaller individuals could be cornered by a larger animal. All the bears had dug their own underground dens, invariably in dry sandy south-facing banks, and above ground nests had been positioned where they had good views of the approach of visitors or keepers.

From visits to safari parks housing bears, we observed that although many of the enclosures were large, from 4 to 6 ha, they were flat to permit vehicle access to all parts and to enable the staff to round up the bears at night. This terrain seemed to be lacking in interest both for visitors and the occupants and it was clear from our observations at Loch Lomond, where the animals had been housed in an enclosure of nearly 6 ha, that the bears were in the habit of monitoring everything in their field of view.

The Society owns just over 40 ha of land of which only 18 ha had been developed and creating an exhibit of the size contemplated required the provision of secure boundary fencing for part of the undeveloped land.

The site selected was situated in a valley containing many mature trees and thick with undergrowth, which we felt would offer the type of 'enriched' habitat to make a sufficiently stimulating enclosure for the bears. Based on experience with Polar bears, it was considered that two connected outdoor enclosures were essential. Both for security and ease of access the indoor quarters and smaller enclosure, c. 0-5 ha, were located on top of the hill. The adjacent enclosure, nearly 1-5 ha in extent, incorporated a section of the thickly wooded, 35 degree slope and part of a stream which flows through the bottom of the valley

Because of the steepness of the terrain, the fencing, 900m in length, proved extremely difficult to erect in places. In accordance with the recommendations of 1981 Zoo Licensing Act, the fence wire is buried to a depth of at least 1m with an inward facing return of 1m. A 1m wide concrete pathway runs around the inside of the fence of the top enclosure. Above ground the 2.5 m high weldmesh fence is topped by 1.2m of corrugated iron along its entire length to prevent the animals from climbing over it. Although the iron is potentially unsightly, discreet painting and careful siting close into the bank or against hedging, as well as additional planting on the outside of the fence, has softened its impact considerably. The 120 m long section of fencing along the valley bottom is almost invisible on the other side of the valley because it is tight into the banking below and hidden by vegetation. As electric fencing is not in general effective for bears, the alternative would have been a prohibitively expensive 3.5 m high brick or blockwork wall. The cost of the perimeter barrier is probably the main reason why the majority of zoo bear enclosures world-wide are still too small. This group of bears was 'fence trained' on arrival and have never attempted to climb the fence. We appreciate that to release bears used to traditional zoo 'cages' into such an enclosure might be more difficult.

When the bears were on the platform in the top enclosure, the corrugated sheeting obscured the visitor's view and it has been replaced in two places with 6 mm bullet-proof clear plastic Lexan sheeting. Although this material will scratch (there is a more expensive non-scratchable version), as it is above head height for both humans and bears, this has not been a problem. We are now experimenting with alternatives to the corrugated iron and in time we intend to replace it wherever possible where it is in public view.

THE HOUSE

The indoor accommodation consists of four interconnecting dens with weldmesh fronts and a service area which includes a food preparation section. The den sizes were based on the bear dens at West Berlin Zoo (Klos, 1974), the two outer dens measuring c. 4 x 2.3 m and the two smaller dens c. 2.6 x 2.6 m. They are c. 2.2 m in height and roofed with pre-cast concrete which enables the full height to be used for the animals and also allows for wire hawsers to be run above the concrete slabs to control the heavy steel guillotine exterior doors, which give access to the outside enclosure. These doors, which are operated from the service area, are counterweighted to assist lifting and enable a keeper to offer food items through the weldmesh at the front of the den to keep the animals' attention while the doors are closed. They can be locked into the open or closed positions and since the bears, assisted by the counterweight, are able to open them from outside, this has proved to be an essential feature when keepers are working in the dens. The sliding doors between dens are top hung on bogie wheels housed in a mild-steel track, there is no bottom runner and only short self-clearing brackets are required to hold the door securely.

Each den is fitted with a wooden platform, 1.5 m high, onto which the bears climb to rest and feed. We tried to simulate the tree nests of wild bears by providing hanging baskets, two of which are bolted into the corners 2m from the floor in the larger dens. The baskets are about 1 m deep and consist of flat and round bars, lined with weldmesh to retain the bedding. The two central dens are fitted with single, smaller, less deep baskets. Since bears avoid soiling their nests, by defecating and urinating over the rim keeping their bedding material clean and dry, the provision of these has not only been popular with the bears but also simplifies cleaning procedures.

In use, we found that one modification was desirable. Although the bears are good climbers, we noticed that when climbing down from the nests or ledges the females were cautious, lowering themselves backwards and feeling with hind paw for a projection for support. We therefore arranged for short blunt metal crossbars to be welded to the uprights and these are now used routinely by the bears when descending.

Although the dens are fairly warm and well-ventilated, we believe they would be improved with the addition of underfloor heating and we hope to install this in due course.

UPPER ENCLOSURE

The 0.5 m upper enclosure, connecting with the house, is the bears' 'adventure playground' and feeding area. A wooden structure with four platforms placed at increasing heights made of telegraph poles and wooden planks allows food to be presented in a variety of ways as well as giving the bears a view which covers most of the Zoo. The legs of the structure have wooden pegs fitted at various heights on with food items can be speared. Some of these can just be reached by the animals with their claws while standing upright, while others require them to climb the poles to reach them. To facilitate climbing in wet weather hemp rope has been wound in a spiral on some of the platform legs. From one of the lower platforms, a notched pole slopes to the ground at an angle of 50-55 degrees with a blunted hook attached to its underside some three-quarters of the way up from which food is hung. The bears must have a good balance to climb the pole and retrieve the food.

The tallest platform is c.5 m From the ground and although the male does go to the top without hesitation, we believe that it may have been an improvement if the construction had been spiral so that the animals always had a wall against each shoulder when ascending or descending.

Four clay pipes, 23 cm in diameter and 45 cm deep with 2.5 cm of gravel at the bottom for drainage, have been sunk into the ground to hold food items which the bears scoop out with their paws or stab with their claws. The bears, taking great care, can remove uncooked eggs from the pipes without breaking them. A 1 m length of piping of the same diameter is left in the enclosure with food inside just out of paw reach and the bears must roll the pipe, which has a flare jointing lip at one end, to cause the food to fall out of the end. Scatter feeds of raisins and other small items are spread around the enclosure or hidden in a large pile or rocks to encourage the animals to forage. The rock pile also enables the bears to avoid one another in times of conflict or stress.

A heavy duty plastic fish farm tank 3 m in diameter and 1 m deep with a 1800 litre capacity was sunk into the ground as a pool. Rosenthal (unpubl.) observed that Black bears at Oklahoma Zoo were afraid to use a pool if it was too deep. When the pool was first introduced we scattered food in it to encourage the bears to use it and were interested to see them retrieve carrots, which had sunk to the bottom, by feeling with the hind paw and lifting the food out between the claws. Our bears enjoyed the pool especially during a spell of unusually hot weather when the male which appeared to be particularly distressed by the heat, spent many hours in the water. We intend to add a further two or three similar pools to reduce competition for the facility. Other additions that we hope to install are more logs and pipes, heavy rope hammocks supported between the uprights of the platform, a 4 m tall honey log, and a number of metal baskets on legs with pitched roofs to provide each bear with a relatively private, draught and damp-free, outdoor bed in full view of the public.

VALLEY ENCLOSURE

The large wooded enclosure is reached from the feeding area via a top-hung sliding door of similar pattern to that used between the indoor dens. The valley has been left as natural as possible with no additions of artificial furniture. There are several mature trees growing to heights of 15 m or more, small younger trees of various species and an overgrown hawthorn Crataegus hedge, with a flourishing undergrowth of brambles, thistles, rose-bay willow herb and ferns. The enclosure encourages the bears to carry out a wide variety of behaviours, including different types of feeding, such as grazing, digging for roots and tearing apart decaying logs, presumably in search of grubs. They also eat wild berries and climb the hawthorn bushes to reach the ripe fruit in the autumn.

Research in the wild has shown that Black bears can seriously damage favoured feeding trees and 'some are so damaged that little beyond the tree trunk and branch stumps remain' (Schaller et al.,1989). In time it will probably be necessary to protect some of our mature trees with guards.

To encourage more widespread use of the enclosure, the keepers have devised a system of scent trails. This simple technique consists of tying a 'smelly' food item (meat or herring) onto a piece of twine and trailing it around the enclosure. To avoid predictable hunts not all trails lead to a reward.

BEHAVIOUR

The bears make nests in the trees and on the ground. The male is a particularly skilled nest builder and has several beds usually sited at the foot of a mature tree, which he uses in turn depending on the weather conditions. The nests are similar to those described in the wild (Schaller et al., 1985), being constructed of 20 or 30 shoots or small branches broken off from a nearby tree or bush, ash Fraxinus excelsior or willow Sulix are favoured by our animals, and lined with twigs, grasses and leaves. One of the nests showed evidence of careful construction with the branches interwoven in an elaborate manner rather than piled haphazardly in the concave at the tree's base. One of the females made a feeding nest 8 m above ground in the fork of a horse chestnut Aesculus hippocastanum, constructing it, in the manner of wild bears, by bending the nearby branches, chewing off the shoots and piling the bent or broken branches below her to form a crude platform, the remains of which could still be seen the following February after the winter storms.

The bears have also dug wet weather dens into the hillside and under an old tree root. The latter, built by the male is often used and added to, the animal scraping out the soil and lining the nest with large twigs and dried grasses. These wet weather nests have been used in winter for a period of several days for semi-hibernation.

The bears are seasonal in their activity and if allowed will feed voraciously in late summer to gain weight for semi-hibernation during the winter. If they are not allowed to feed to their maximum capacity they will remain active throughout the winter months. Our bears show a substantial weight gain during the summer and it is difficult to supply them with enough food to satisfy them. In the winter they retire to their indoor baskets for months at a time. Even the presence of the noisiest keeper does not seem to disturb them and, since it is not possible for the bears to descend from the baskets quickly even if they do wake, the cage area under the basket can be cleaned without fear of injury.

The bears have a wide range of vocalisations. A loud "tut tut", apparently made by the bear snapping its tongue against the roof of its mouth, seems to be used as one bear approaches another but is never used towards the keepers. A loud hiss, caused by a fast exhalation of breath is used as a threat or warning.

Perhaps the most alarming sound that the bears produced was heard when they were involved in squabbles during the introductory period. A very loud human-like scream, leading one to believe that the fighting was causing nothing less than fatal injuries, was produced but when the bears were separated little sign of damage could be found and it would seem that their huge neck ruffs protect them.

CONCLUSION

At the end of 1989 the exhibit housed a 1.4 bears, the male being particularly active. The design of the exhibit was intended to eliminate the major criticism of keeping of bears in captivity, that is, the lack of sufficient stimulation, leading to stereotypic behaviour. The large foraging enclosure and the many artefacts in the top enclosure provide a continuous source of changing interest.

One of the concerns expressed at the plan was the enclosure was so large and contained so much undergrowth that the visitors would have difficulty in seeing the animals. In practice this has been found not to be so. When necessary, the bears can be easily enticed into the top enclosure and they are frequently on view resting on the platforms rather than hiding in the vegetation. We apparently underestimated the interest the bears take in the people.

ACKNOWLEDGEMENTS

The Society would like to thank the many individuals and organisations for their help in the complex project. In particular our thanks go to:

  • The St Andrew Animal Fund
  • Scottish Animals Rights Network;
  • Scottish Society for the Prevention of Vivisection;
  • Animal Concern Ltd;
  • Scottish Society for the Prevention of Cruelty to Animals;
  • Roger Wheater, Director of Edinburgh Zoo;
  • Barry Pape of Ravensden Zoo;
  • J. Clubb of Clubb-Chipperfield;
  • Manpower Services Commission;
  • National Federation of Zoological Gardens of Great Britain and Ireland.

We would also like to thank the members of our Zoological Society, the staff and our veterinary surgeons for their constant encouragement and help.

PRODUCT MENTION IN THE TEXT

Lexan: polycarbonate sheeting, manufactured by GE Plastics Ltd. Birchwood Park, Risley, Warrington, Cheshire, Great Britain.

REFERENCES

  • Klos, H.-G. (1974): New bear exhibit in the West Berlin Zoo. Int. Zoo Yb. 14: 223-225.

  • Law, G., Boyle, H. & Johnston, J. (1986): Notes on polar bear management at Glasgow Zoo. Ratel 13(2): 56-58.

  • ROSENTHAL, M. (Unpublished): Lincoln Park Zoo management survey of bears in captivity. Internal report 1988.

  • SCHALLER, G. B., JINCHU, H., WENSHI, P. & JING, Z. (1985): The giant pandas of Wolong. Chicago: University of Chicago Press.

  • SCHALLER, G. B., QITAO, T., JOHNSON, K. G., XIAOMING, W., HENIINC,, S. & Jinchu, H. (1989): The feeding ecology of giant pandas and Asiatic black bears in the Tangjiahe Reserve, China. In Carnivore behaviour, ecology and evolution: 212-241. Gittleman, J. L. (Ed.). London: Chapman & Hall.