Investigation on Perception and Behavior of the American Black Bear (Ursus americanus)

Behavioral information concerning the American black bear Ursus americanus is limited. The present study was conducted to assess various aspects of ingestive behavior and visual discrimination of the black bear using two captive females. Information available pertaining to the management of black bears in captivity is also limited. Therefore a large portion of the study revolved around the care and maintenance of the bears in a semi-natural enclosure.

The ingestive behaviors were studied using ethological observations and a longitudinal food preference test. Observations were obtained as the subjects procured and consumed food items both naturally occurring and introduced into the enclosure. The observed feeding behaviors were discussed in three categories: foraging, predation, and consumption. The foraging behaviors appeared to be uncomplicated and consisted primarily of apparently random walking and use of the front paws to dig and manipulate objects in the enclosure. Olfactory scanning was integrated with locomotion and use of the paws. Predatory behaviors were infrequently observed but are described.

Detailed descriptions of the consumption of the native food items (acorns, blackberries, and grass) were based on motion picture analysis. Visual orientation toward the food items was particularly evident and is considered an important facit of the ingestive behaviors. The bears were also found to be very clean feeders, consuming very little debris.

The preferences for two sets of food items (native food items and non-native food items) was determined during a one year testing program. The bears were found to exhibit definite scalable preferences among both sets of foods. The preferences were significantly correlated between the subjects and were consistent throughout the one year period. The consistency of preference among seasons indicated that the naturally occurring diet of the black bear is controlled by availability of the foods. In the native food test acorns were the most preferred. In the non-native food test fish was the most preferred food.

The foods most highly preferred were rich either in protein or carbohydrates. The carbohydrate preference, unusual for a member of the order Carnivora, is considered a function of the change to herbivorous dietary patterns in the bear.

The research on visual capacities of the captive bears consisted of two discrimination studies. The bears were tested for their abilities to perform discriminations on the basis of hue and pattern using specially designed methods involving small painted containers. The basic task was a two-choice correction procedure with food reinforcement.

The results of the color vision testing indicate that blue was successfully discriminated from gray, green, red, and yellow. Green was successfully discriminated from gray, blue and red. The acquisition of the discriminations was very rapid. The consistency of the hue discrimination and the rapidity of learning indicated that the subjects were very adept at hue discrimination and, most likely, utilized this ability with frequency.

The form discrimination study was designed to assess one bear's abilities to differentiate and recognize patterns. It was found that the ability to choose the correct stimulus was not affected by size of the stimuli, configurational placement, or the introduction of novel negative stimuli. The reversal of backgrounds produced an initial but very short period of confusion.

The retention of the discrimination was found to be perfect after four and eight month delays. The rate of learning the initial discrimination was also very rapid. It was concluded that the bear was very capable of making visual discriminations on the basis of pattern.