Indicating acts during counting by a chimpanzee (Pan troglodytes).

Indicating acts during counting by a chimpanzee (Pan troglodytes).

A chimpanzee (Pan troglodytes) experienced in counting arrays of 0-7 items and trained for comprehension of number symbols, spontaneously displayed a variety of indicating acts (e.g., pointing, touching, and rearranging items) during counting. Twenty-five sessions were videotaped, and all trials were evaluated for the relations among number of items presented, number of indicating acts displaye...

Chimpanzee (Pan troglodytes) Counting in a Computerized Testing Paradigm

Numerical competence in a chimpanzee (Pan troglodytes).

A chimpanzee (Pan troglodytes), trained to count foods and objects by using Arabic numbers, demonstrated the ability to sum arrays of 0-4 food items placed in 2 of 3 possible sites. To address representational use of numbers, we next baited sites with Arabic numbers as stimuli. In both cases performance was significantly above chance from the first sessions, which suggests that without explicit...

Visual texture segregation by the chimpanzee (Pan troglodytes).

One adult male chimpanzee (Pan troglodytes) was trained to detect a target area consisting of texture elements from the background texture made of the different elements from the target area. The subject was given eight different stimulus conditions. In Condition 1, segregation was based on the difference of local feature of elements but not on global similarity. Conditions 2-3 investigated the...

A case of maxillary sarcoma in a chimpanzee (Pan troglodytes).

Oral malignancy is rare in chimpanzees. A 34-year-old female chimpanzee (Pan troglodytes) at Kumamoto Sanctuary, Japan, had developed it. Treatment is technically difficult for chimpanzees while malignant neoplasm is seemingly rising in captive populations. Widespread expert discussion, guidelines for treatment, especially for great apes in terminal stages is urgently needed.