Published Papers - Matsumoto Akiko

Activity budgets of wild female chimpanzees in different reproductive states

A Matsumoto-Oda, R Oda

JOURNAL OF ETHOLOGY ( JAPAN ETHOL SOC )  19 ( 1 ) 17 - 21   2001 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Activity budgets of wild female chimpanzees (Pan troglodytes schweinfurthii) when lactating were compared with those during estrus and anestrus. Five anestrous females, seven estrous females, and three lactating females in Mahale Mountains National Park, Tanzania, were the subject of focal sampling. Time spent for feeding, resting, and moving was examined. For each of these three categories of activity, there was no significant difference of time spent for each activity between lactating females and either estrous or anestrous females. The females spent about 30% of their daytime feeding, about 40% resting, and about 30% moving. One of the reasons for the lack of difference might be the type of parties that females attended when they were observed. In most cases, the females were seen in large bisexual parties. Although lactating females are expected to need more nutrition than cycling females and this might affect their activity budget, the party type they attended might also affect the budget.

Predation of mammals by the chimpanzees of the Mahale Mountains, Tanzania

K Hosaka, T Nishida, M Hamai, A Matsumoto-Oda, S Uehara

ALL APES GREAT AND SMALL, VOL 1: AFRICAN APES ( KLUWER ACADEMIC/PLENUM PUBL )    107 - 130   2001 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Preliminary study of feeding competition between baboons and chimpanzees in the Mahale Mountains National Park, Tanzania.

Matsumoto-Oda A, Kasagura MB

Afr Stu Monogr   21   147 - 157   2000 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Female choice in the opportunistic mating of wild chimpanzees (Pan troglodytes schweinfurthii) at Mahale

A Matsumoto-Oda

BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY ( SPRINGER VERLAG )  46 ( 4 ) 258 - 266   1999.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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For female chimpanzees (Pan troglodytes schweinfurthii) in the Mahale Mountains National Park? Tanzania, the most common mating pattern is opportunistic. In such opportunistic matings, females copulated promiscuously but not randomly. This study describes female mate choice during 1-year observation of six females who exhibited regular genital-swelling cycles. During the study period, 169 opportunistic matings and four restrictive matings were recorded over the course of 51 days. As female estrus progressed, mating frequency and the number of adult male mating partners increased, although the number of potential mating partners did not change. Criteria of female choice examined were the direction and consent/rejection of courtship, proximity maintenance, and female grooming. Adult-male courtships were successful more often than those of adolescent males. During the earlier phase of estrus, females copulated rather promiscuously with many males. But during the later phase of estrus when the likelihood of conception is expected to be highest, they copulated repeatedly with high-ranking adult males. There was a positive correlation between female grooming frequency and mating frequency when the likelihood of conception was greatest. Female chimpanzees are thought to choose high-ranking males as fathers of their offspring. Moreover, female chimpanzees may adopt one or both of two mating strategies, i.e., a many-male strategy and a best-male strategy.

Nutritional aspects of fruit choice by chimpanzees

A Matsumoto-Oda, Y Hayashi

FOLIA PRIMATOLOGICA ( KARGER )  70 ( 3 ) 154 - 162   1999.05 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Mahale chimpanzees: Grouping patterns and cycling females

A Matsumoto-Oda

AMERICAN JOURNAL OF PRIMATOLOGY ( WILEY-LISS )  47 ( 3 ) 197 - 207   1999 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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The social system of chimpanzees (Pan troglodytes schweinfurthii) is characterized by the fission-fusion of social groups. Several studies have reported that females are less gregarious than males. In the current study, adult female gregariousness depended on their reproductive state. Noncycling adult females (pregnant, lactating, or post reproductive) were observed in large bisexual parties less often than cycling adult females. On the other hand, cycling adult females were observed in large bisexual parties as often as males, regardless of their estrous state. More males were in parties that included cycling adult females with maximal genital swelling (estrous females) than in parties without them. Moreover, a bisexual party including more estrous females contained more males. These results suggest that large bisexual parties of chimpanzees are constructed by a dual mechanism. First, cycling adult females are attracted to parties that consist of the top ranking male and large numbers of adult and adolescent males. Second, adult and adolescent males that did not belong to parties originally are attracted by estrous females and join them. Thus, in Mahale Mountains National Park, Tanzania, bisexual parties of chimpanzees can be characterized as "parties for reproduction." Am. J. Primatol, 47:197-207, 1999. (C) 1999 Wiley-Liss, Inc.

Factors affecting party size in chimpanzees of the Mahale mountains

A Matsumoto-Oda, K Hosaka, MA Huffman, K Kawanaka

INTERNATIONAL JOURNAL OF PRIMATOLOGY ( KLUWER ACADEMIC/PLENUM PUBL )  19 ( 6 ) 999 - 1011   1998.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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We studied factors affecting party size and composition of wild chimpanzees at Mahale (M group) over an 11-month period Parties with 1-5 individuals were most frequent (37.8%; 153/405 parties), they included 94.7% of all male pm-ties (n = 76) and 81.3% of all female parties (n = 75). The median of monthly values was the standard for analysis. We divided the year into four period based on the median size of monthly bisexual parties (30.9 individuals; includes both males and females): monthly bisexual party sizes were larger in May-June (period II) and October-January (period IV) and smaller in February-April (period I) and July-September (period III). Only bisexual parties changed in size with period. The number of fruit items (=species) eaten was fewer in periods II and IV when abundance per item appeared to be great. The sizes of bisexual parties, which included cycling females with maximal anogenital swelling, were larger, and their representation (%) in all bisexual parties was greater in period III and IV. The numbers of both cycling females and cycling females with maximal anogenital swelling were also larger in period III and IV The percentage of cycling females with maximal anogenital swelling was greater in period II and III. The results of this study and those of Nishida (1979) suggest that seasonal variation in party size of Mahale chimpanzees maintains a relatively consistent annual cycle. The factors assumed to affect party sizes are fruit availability and the presence of cycling females with maximal anogenital swelling.

Injuries to the sexual skin of female chimpanzees at Mahale and their effect on behaviour

A Matsumoto-Oda

FOLIA PRIMATOLOGICA ( KARGER )  69 ( 6 ) 400 - 404   1998.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Changes in the activity budget of cycling female chimpanzees

A Matsumoto-Oda, R Oda

AMERICAN JOURNAL OF PRIMATOLOGY ( WILEY-LISS )  46 ( 2 ) 157 - 166   1998 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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This study is a preliminary report on the time allocated to various activities by female wild chimpanzees (Pan troglodytes schweinfurthii) during their sexual cycle. Cycling females with maximal tumescence (estrous females) tended to spend more time moving than cycling females with quiescent sexual skin (anestrous females). Although there was no statistically significant decrease in any specific activity that corresponded to the increase in time spent moving, feeding time did decrease in four of the five females. The frequency of approach by females toward males and the frequency of approach by males toward females significantly increased when females were in estrus. Direct aggression by males occurred more frequently toward estrous females than toward anestrous females. The copulation frequency and the frequency of approach to males was not significantly correlated with the increase in time spent moving. There was a high but not significant correlation between the time spent moving and the frequency of direct aggression by males toward females. Mating effort, feeding competition, male aggression, and other possible reasons that might explain the increase in moving time are discussed. (C) 1998 Wiley-Liss, Inc.

Self-suckling behaviour by a wild chimpanzee

A MatsumotoOda

FOLIA PRIMATOLOGICA ( KARGER )  68 ( 6 ) 342 - 343   1997.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

First record of a twin birth in chimpanzees of the Mahale Mountains National Park, Tanzania.

Matsumoto-Oda A

Afr Stu Monogr   16   159 - 164   1995 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)