engleski

What should we know when reintroducing "rehabilitated" brown bears?

Brown bears are very unique animas: as the largest terrestrial carnivores they feed predominantly on vegetation. Therefore they are very demanding towards the habitat they live in. They need large unfragmented areas with good vegetation cover and low disturbance. Depending on geographical latitude and general habitat quality an individual bear may roam over 100 km2 up to 100.000 km2. Bears walk in search for food, sexual partners and to avoid other bears of the same sex. Vegetation provides hiding cover and must comprise of various plant species that provide food in different seasons. Bears need less than 10% of proteins in their diet and most of that they do satisfy by insects and other invertebrates and eventual carrion. Human caused disturbance may interfere with the reproductive cycle, especially during winter hibernation when female gives birth. Most of the skills required for survival under this conditions of continuous search for what is needed and in avoidance of trouble bears learn during the first two years of their life in nature while accompanied with their mother. Each bear develops his own behavioral strategy exhibiting individualism rarely seen in animal kingdom. The only common component may be the opportunism; bear quickly learns to go easier way whenever possible. When this concerns the relation to man, the opportunistic behavior is typically not the safe way of life. Through the mechanisms of natural selection, however, many mothers fail to successfully raise their offspring: cubs may be killed by an adult male, may die in an accident or simply starve. There are the cases, too, that the mother dies while nursing. Chances for survival of orphaned cubs are directly proportional with the length of time they spent with the mother. Due to opportunistic behavior orphaned cubs occasionally survive by searching food from human sources. They become habituated to people and as nuisance individuals never last long; either have to be killed or do die in traffic accidents. Acceptance of bears as part of our natural environment directly depends on how much they effect the living of local human population. The bears that cause considerable damage or even threat human lives are highly unacceptable. It is the individual bear behavior that makes most of the difference, although the bad things done by a single bear are typically blamed to the entire bear population. Any situation that stimulates creation of problem bears should be avoided as the matter of the first priority. Open garbage dumps in bear habitat are one of such places where bears may learn and adopt the undesirable behavior. It is nearly impossible to hand raise orphaned wild or captive born bears in the way that will develop all skills necessary for their life in nature and to behave properly in relation to man. The problems of releasing "rehabilitated" bears in areas with low human population and with healthy bear population are mainly the questions of their survival and eventual successful reproduction in wild. That could be measured by intensive radiotelemetry tracking. Considering that the measures against possible gene pollution by mixing foreign populations have been implemented, each successfully reintroduced cub can be welcomed as a merely ethical achievement. Biologically this addition to viable population is negligible. On the other hand bear populations that are critically low and typically in a human dominated surrounding can not afford the risk of adding a bear with potentially unacceptable behavior. Even for reintroductions from other wild populations extreme care has to be taken to decrease the risk of bringing the misbehaving individuals. In conclusion I propose the investments in efforts to prevent the situations where wild born bears become orphaned and to prevent the birth of unwanted captive bears. The existing captive population should be given the best possible care and used as ambassadors to raise public awareness about situation of free-living consepcifics.

brown bear; rehabilitation; captive; hand raised

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