Providing appropriate amounts of space is a critical, but often overlooked, aspect of polar bear husbandry. Space allocation is arbitrary and often seems to be based more on convenience and finances than on the biological and behavioural requirements of the animals themselves.
All captive animals must be provided with space appropriate to their needs. A good rule to follow is the bigger the better. There is no upper limit. It is far better for an animal to have more space than it needs, than for it to need more space and not have it.
When considering the spatial requirements of polar bears in captivity, it is important to consider the fact that polar bears inhabit enormous territories in the wild. In his book Bears, Majestic Creatures of the Wild, biologist Ian Stirling comments on the range of wild polar bears,
According to The Great Bear Almanac, the range of a single polar bear is more than 51,800 sq km (20,000 sq miles). In fact, polar bears inhabit the largest living space of any terrestrial animal species.
While many polar bears spend a great deal of time in terrestrial habitats, they may also spend considerable time in aquatic environments. In fact, polar bears are capable of swimming enormous distances in the wild and are classified as marine mammals in the United States. In 2005 scientists reported that they had tracked a tagged polar bear as it swam a distance between 74 km (46 miles) and 99 km (62 miles) in a 24 hour time period. While it has long been known that polar bears swam great distances, this was the first time such a long swim had been scientifically tracked.
According to Gary Brown in The Great Bear Almanac,
Another almost universally ignored aspect of polar bears is their ability to climb a variety of natural features. In The Great Bear Almanac, Gary Brown states that the polar bear is an "... agile climber of ice ridges; climbs to travel and pursue prey. Can jump/scale over six-foot high ice barriers; can jump down ten feet; can scale a thirty-five foot ice wall”. Yet zoos the world over ignore this fact and house polar bears on predominantly flat surfaces.
Polar bears have traditionally been kept in barren concrete floored enclosures (grottoes) surrounded by walls, often with a dry moat in front so spectators can view them at eye level. These exhibits were constructed this way for several reasons, including security, ease of maintenance and erroneous ideas about the pack-ice environments that wild polar bears inhabit. The practice of maintaining polar bears permanently on hard floor surfaces is widespread and persistent, even though hard surfaces are detrimental from a health and behavioural perspective.
Nothing in nature has prepared polar bears for living on concrete. Exhibit designers often think that concrete simulates the look and feel of pack ice, but they don't seem to realize that pack ice differs dramatically in appearance, texture, consistency and every other aspect. Unlike real pack ice, the surface consistency of molded concrete tends to be uniform and alien. In the wild, polar bears walk over a broad range of ice and snow substrates, as well as natural rock and earth substrates. They will construct nests and dig burrows when given the chance. Simulated concrete ice is not biologically or behaviourally relevant to polar bears.
In The Behaviour of Captive Polar Bears, Alison Ames indicates that all polar bears, including those in captivity, actually prefer soft substrates:
Substrate preference of a captive, male/female pair of polar bears was recorded following the addition of natural substrates to their concrete enclosure. A total of 60 hours of observations were collected. The substrate on which these bears were lying, rubbing, feeding, or digging was recorded. For all of these behaviours, the male spent at least 78% of the total activity time in the natural areas. The female was observed to use the natural pits for 19% and 21% of feeding time and lying time respectively. 75% of the male’s foraging time occurred in either the water or a natural area while 60% of the female’s foraging occurred in these areas. The female’s use of the natural pits was much reduced because the male monopolized the areas. The captive animals’ preference for softer substrates was supported by observations collected on the ecology of wild polar bears in the Churchill area of Canada’s Hudson Bay. Wild bears were observed over a three month period during the autumn of 1991. Over 77% of the bears seen on the inland tundra were found in either heavily wooded areas along the sides of streams or lakes or in areas covered in lichens and berries. Along the coastline, over 80% of the polar bears were on sand banks or tall grass areas. As snow began to accumulate, the majority of bears rested in snow banks, kelp or willows.
Some populations of wild polar bears spend up to five months of the year moving across beaches and through inland tundra. Nothing in a polar bear's biology or behaviour has prepared them for living permanently on hard surfaces.
In an ideal world, all polar bears currently held in captivity would be moved to expansive, complex, naturalistic paddocks that allow them to roam and behave normally. Unfortunately, those kinds of captive situations are few and far between and many zoo resist the idea that their facilities are inadequate. Many still claim their existing old style enclosures are adequate and that their polar bears are stimulated through programs of environmental enrichment.
Environmental enrichment is a process for improving captive animal environments within the context of their behavioural biology and natural history. Enrichment involves changes to objects, structures and husbandry practices that facilitate the expression of species-typical behaviours and increase behavioural opportunities.
While environmental enrichment is often touted as a solution to a broad range of problems and can be a useful strategy for improving zoo animal welfare in some cases, it tends to address the symptoms of the problems rather than the problem itself (i.e., inherently deficient captive environments).
Veterinarian Samantha Lindley warns against seeing environmental enrichment as a panacea for polar bears in captivity:
Polar bears have long been known as a species that is especially prone to the development of abnormal behaviour patterns in captivity. These usually manifest themselves as stereotypic pacing, head turning and swimming patterns. Stereotypies are prolonged, repetitive, apparently purposeless behaviours that do not occur in the wild. They are usually associated with substandard conditions and poor welfare.
Even zoos with the largest budgets have difficulty keeping polar bears free of stereotypic behaviours. Sea World San Diego has not been able to stop the development of stereotypies in their polar bears despite spending millions of dollars on their polar bear exhibit. Sea World Gold Coast Australia has had the same experience. The Calgary Zoo in Alberta and the Central Park Wildlife Centre in New York have put polar bears on prozac to reduce abnormal behaviour patterns.
Zoo consultant Stephan Abbott Ormrod in his report A Review of Captive Polar Bears in Great Britain and Ireland is convinced that
The unique biology and behaviour of polar bears make them extremely poor candidates for captivity. It is doubtful that an enclosure could be constructed (especially in an urban setting) that would satisfy their full range of needs and prevent the development of aberrant behaviours.
Clear, hollow guard hairs comprise the outer layer of hair. These serve to reflect light down the shaft of the hair where it is absorbed by the polar bears black skin, another unique adaptation to the cold.
Fur covers the entire body except for the nose and footpads, and the ears and tail are small and rounded to reduce heat loss. The nose is long and helps warm cold air as the bear inhales. Hair between the foot pads provide additional protection from the cold, while the large paws aid in swimming, traveling on and shoveling snow.
Captive polar bears in warm climates often develop greenish-tinged fur due to algae growth in the hollow sheath of the guard hairs. While this may not directly impact the physical health of the bear, it is unnatural, unsightly, an indication of inappropriate conditions and it gives the visiting public a distorted view of polar bears.
Walking and swimming across large expanses of arctic territory have also led to the development of behaviours specific to cold weather environments. One hunting behaviour involves the bear pushing a block or mound of snow ahead of itself for concealment during seal stalks. Another involves an underwater stalk below the sea ice.
Polar bears are very clearly adapted to a wide-ranging life in arctic conditions. Nothing in their physical or behavioural makeup prepares them for life in confined, consistently warm environments.
New Exhibit Bells and Whistles
In recent years, some southern zoos have attempted to mitigate the effects of climate through air-conditioned dens, refrigerated pools, ice machines, specially-designed shade cloth, fans and other measures. While these measures may offer some short-term relief, they are stopgap measures that do nothing to address the larger problem of an arctic animal being kept in an inappropriate climate. The animals still experience high temperatures and humidity that they would never experience in the wild.
Veterinarian Samantha Lindley expresses concern about polar bears in warmer climates: