Institute, 2020). Hence, understanding their dietary needs is an effective means to study the behavior, ecology, and evolutionary history of target species.Mammals can be roughly divided into three groups according to their diet: carnivores, omnivores, and herbivores. Plants are the primary food source of herbivores and are a relatively abundant resource in the environment. The composition of plant tissue is quite

Although most felids have an exclusive carnivore diet, the presence of plant matter in scat has been reported among various species. This indicates that there may be an adaptive significance to the conservation of plant-eating behavior in felid evolution. Some studies have hypothesized that felids consume plants for self-medication or as a source of nutrition. In addition, it is thought that plant intake helps them to excrete hairballs, however, no scientific work has confirmed these effects. Thus, the objective of this study is to investigate the relationship between plant intake and hair evacuation in felid species. We selected snow leopards ( Panthera uncia ) as the study species because they have longer and denser hair than other felids. The behavior of 11 captive snow leopards was observed and scat samples from eight of them and two other captive individuals were analyzed. Snow leopards evacuate hair possibly by vomiting and excreting in scats. The frequency of plant-eating and vomiting and the amount of hair and plant in scat were evaluated. We found that the frequency of vomiting was much lower than the frequency of plant-eating. In addition, there was no significant relationship between the amount of plant matter contained in scats and the amount of hair in scats. Contrary to the common assumption, our results indicate that plant intake has little effect on hair evacuation in felid species.

The field of environmental enrichment has grown considerably, but most enrichment is still focused on tasks where highly valued food rewards are directly visible. We designed a device which would instead make use of knowledge states, motivational structure, and physical reasoning skills and could use hidden, low‐quality food items while remaining low in cost. Food items were hidden in small cardboard tubes and placed snugly inside another, larger, tube such that they were difficult to extract and presented a challenging dexterity and physical reasoning task. Rare favored food items were distributed so animals would be rewarded at irregular intervals. The devices were then presented to two groups of chimpanzees (Pan troglodytes) who either had experience extracting food from identical small cardboard tubes or had no such experience. We found that the chimpanzees with no prior experience with the small tubes used the device very little until one individual removed a small tube, revealing the food inside, at which point use time significantly increased. In the knowledgeable group, no change was observed after the first tube retrieval. Individuals in both groups used the devices for over 20 min each on average over a 1‐h observation period, and in both facilities at least one device still contained all inner tubes. Our study suggests that enrichment can make use of animals' prior knowledge, that enrichment devices can thus be layered into one another, and reiterates the importance of considering animals' psychology in designing enrichment.