Male chimpanzee behavior in relation to female ano‐genital swelling

Abstract

This study examined the relationships between male agonistic, affiliative, and sexual behaviors and female estrus condition in captive adolescent and young-adult chimpanzees (Pan troglodytes). Data on agonistic, affiliative, and sexual behaviors of 11 males living in three social groups were collected during daily 45 minute observations over a 5 month period. Female estrus condition was assessed daily using the relative size of the female's ano-genital swelling. It was hypothesized that the presence of maximally tumescent females would generate conflicts between males, so an increase in inter-male agonism was predicted. Males exhibited higher rates of agonism toward other males when at least one female in the group was maximally tumescent. Male affiliative behavior directed toward other males and social play with males were affected by the presence and number of maximally tumescent females. Male sexual behaviors increased when maximally tumescent females were present.

Male Dominance Rank, Female Mate Choice and Male Mating and Reproductive Success in Captive Chimpanzees

“…For both males and females the rates of all behaviors increased significantly with the degree of swelling intensity. Thus, our data are consistent with those reported previously for other chimpanzee groups in captivity by Wallis (1992) and Shefferly and Fritz (1992) and in the wild by Tutin and McGinnis (1981) and Goodal (1986) and are also in line with data from other primate species, in which female attractivity, proceptivity and receptivity are related to the degree of swelling of female anogenitalia (tonkean macaques: Aujard et al, 1998;bonobos: Reichert et al, 2002). Via hormonal information on the timing of ovulation to provide a measure of the probability of conception in the Arnhem females, we could provide the first direct evidence that sociosexual behaviors of both sexes are not further influenced by female reproductive status, i.e., likelihood of conception.…”

<Note>Use of a novel human object as a masturbatory tool by a wild male chimpanzee at Bulindi, Uganda

“…In chimpanzees, masturbation occurs commonly in captive settings where it has been linked to restricted rearing, which can impede development of speciestypical social and sexual behaviour (Kollar et al 1968;Rogers & Davenport 1969;Lopresti-Goodman et al 2013). Masturbation by captive chimpanzees is performed by hand, foot or mouth, against a cage wall or screen, or sometimes using a manipulable object (Shefferly & Fritz 1992). In the wild, object-assisted masturbation occurs in male long-tailed macaques (Macaca fascicularis), which stimulate their genitals using stones (Cenni et al 2020).…”

Ovarian hormone concentrations and genital swelling patterns in female chimpanzees with Norplant implants

“…Social behavior is correlated with the presence of a female with genital swelling [Wallis, 1982[Wallis, , 1992Bloomsmith et al, 1991;Shefferly and Fritz, 1992], and genital swelling is under the influence of ovarian hormone secretion [Allen et al, 1936;Graham et al, 1972;Nadler et al, 1985]. The dilemma facing managers of captive chimpanzees is determining which method of contraception will temporarily prevent reproduction in select individuals while, at the same time, not interfere with the normal social behavior of the group.…”