close

Вход

Забыли?

вход по аккаунту

?

Body weights of wild chimpanzees (Pan troglodytes schweinfurthii) of the Mahale Mountains National Park Tanzania.

код для вставкиСкачать
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 723155321 119871
Body Weights of Wild Chimpanzees (Pantroglodytes schweinfurthii)
of the Mahale Mountains National Park, Tanzania
SHIGEO UEHARA AND TOSHISADA NISHIDA
Faculty of General Education, Sapporo Uniuersity, Sapporo 062, Japan
6.
U.) and Department ofAnthropology, The University of Tokyo, Tokyo 113,
Japan (TN.)
KEY WORDS Pan troglodytes schweinfurthii, Body weight, I n t r a
subspecific variation
ABSTRACT
Ten male and nine female habituated chimpanzees (Pan t r e
glodytes schweinfurthii) in the Kasoje area of the Mahale Mountains National
Park, Tanzania, were weighed intermittently between December 1973 and
March 1980 by luring them up a rope hung on a spring balance: six adult
males averaged 42.0 k g and eight adult females 35.2 kg. Seasonal change in
body weight was recognized at least partially; body weights tended to decrease
in the later part of the wet season presumably because of food shortage in the
middle of the wet season. Comparison of body weight among three populations
of the same subspecies suggests that adult female chimpanzees of Mahale
appear to be heavier than those of the Gombe National Park, Tanzania, and
that they seem to be similar to the forest-living counterparts of eastern Zaire.
On the other hand, body weights of adult male chimpanzees from the three
populations do not show significant differences. Perhaps feeding competition
among adult females in a small, isolated habitat is more severe than that
among adult males, which may result in the body weight reduction among
adult female chimpanzees at Gombe.
Among various chimpanzee populations
studied in the wild, only eastern or longhaired chimpanzees in the Gombe National
Park, Tanzania, have been weighed systematically with minimal disturbance; they have
been habituated enough with attractive food
to be induced to climb a rope hung on a
spring balance (Wrangham, 1975; Pusey,
1978; Wrangham and Smuts, 1980). Another
systematic data set on body weight of the
same subspecies in eastern Zaire is available
(Rahm, 19679, but the measurements were
taken when unhabituated individuals were
captured for laboratory research.
Jungers and Susman (1984) point out that
the differences observed among subspecies of
Pan troglodytes may turn out to be as important and instructive to our understanding of
chimpanzee evolution as are those differences seen between pygmy chimpanzees and
the various subspecies of common chimpanzees. However, intra-subspecific variation
should be clarified before inter-subspecific
0 1987 ALAN R. LISS, INC
and inter-specific comparisons are undertaken. This report describes newly compiled
body weight data, collected in the wild by the
same method as that at Gombe, on a third
population of the same subspecies (Z? t.
schweinfurthii) in the Mahale Mountains
National Park, Tanzania, and discusses the
intra-subspecific variation in body weight observed among the three populations.
SUBJECT AND METHOD
Wild chimpanzees of K- and M-groups in
the Kasoje area of the Mahale Mountains
National Park, Tanzania, were weighed between December 1973 and March 1980. Although the chimpanzees of K- and M-groups
have been habituated and provisioned with
sugarcane and bananas since 1966, the
amount of food given to the chimpanzees was
reduced from 1975 onwards. Also, data on KReceived August 18, 1986; revision accepted October 16, 1986.
3 16
S. UEHARA AND T. NISHIDA
TABLE 1. Body weights of adult chimpanzees at Mahale
Condition'
Males
KM
KS
KN
SB
LU
MU
Mean
Females
WB
WW
WT
WS
CH
WL
GW
ND
Body weight (kg)
Mean
Range
No. of days2
Prime: K-group
Prime: K-group
Prime: K-group
Prime: K-group
Prime: M-group
Prime: M-group
34.3
49.6
46.1
42.9
38.8
40.3
42.0
30.3-38.0
47.5-52.0
44.3-49.0
38.0-48.0
38.0-39.5
37.0-44.0
39.2-45.1
Past prime: K-group
Past prime: K-group
Past prime: K-group
Prime: K-group
Prime: K- or Mgroup
Prime (nulliparous):
K-group
Prime (nulliparous):
K- or M-group
Young prime: Mgroup
30.5
38.3
36.2
33.8
41.8
36.0-40.5
33.5-40.5
32.5-35.0
35.5-45.5
1 (Aug. '77)
2 (Aug. '75)
6 (Jan. '74-Seat. '78)
2 (Aug. '75-J;ly '78)
27 (Dec. '73-Mar. '80)
35.3
32.5-38.0
2 (Mar.-Jun. '78)
35.5
33.5-37.5
2 (Nov. '77-Apr. '78)
Mean
30.0
35.2
30 (Jan. '74-Mar. '80)
5 (Aug. '75-Feb. '76)
4 (Jan. '74)
40 (Jan. '74-Oct. '78)
2 (Sept. '75-July '78)
3 (Sept. '75-Sept. '78)
1 (Aug. '75)
33.0-37.2
'Condition when measurements were taken
*On which measurements were taken.
group between 1973 and 1974 were collected that individual on that day. This was done
when the chimpanzees of this group were because values obtained in such cases during
already fed only a small amount of food. the early days of measurement fluctuated
Thus, the effect of artificial feeding on the from one occasion to another. The measurechimpanzee body weight seems to have been ments became easier and more stable as both
reduced to a minimum (Nishida, 1981). To- the chimpanzees and the observers got used
pography, vegetation, and climate of the to the system. Two spring balances were used
study area and outlines of the two chimpan- simultaneously in Myako Camp between Oczee unit-groups are described elsewhere tober 1977 and June 1978 in order to enhance
(Nishida, 1968, 1972, 1979; Uehara, 1982; the reliability of data.
Hiraiwa-Hasegawa, Hasegawa, and Nishida,
Male subjects consisted of six prime adults
1984; Nishida et al., 1985; Collins and Mc- (KM, KS, KN, SB, LU, and MU), two adolesGrew, 1985).
cents (LJ and MS), one juvenile-infant (KB),
Chimpanzees were weighed in camps and one infant (ML). Female subjects con(Myako and Kansyana) by luring them up a sisted of three past prime adults (WW, WT,
rope attached to a spring balance; a banana and WB), five prime adults (WS, WI, CH,
or a piece of sugarcane hanging on a second WL, and GW) and one young prime adult
thin rope was fixed to the top of the main (ND). ML always clung to his mother (WI)
rope, a method basically the same as that when she was weighed, while KB (son of CH)
used at Gombe (Wrangham, 1975; Pusey, began to climb the rope by himself after he was
1978). Ten males and nine females climbed 2 314 years old.
the rope, but most individuals of M-group
refused to do so. The scale was read with
RESULTS AND DISCUSSION
binoculars while the chimpanzee ate or took
Body
weights
of chimpanzees of Mahale
away the food a t the top. A reading was taken
Body weights of 14 adult chimpanzees are
when the subject remained rather still for
several seconds. If one chimpanzee was shown in Table 1. Mean body weights were
weighed more than once on the same day, calculated for the individuals whose meathe median was used as the body weight of surements were taken on more than one day.
Feb. '76
July '77
Aug.-Oct. '77
Nov. '77Jan. '78
Feb.-Apr.
'78
May-July
'78
Sept.-Oct. '78
Feb.-Mar. '80
L.W.
E.D.
L.D.
E.W.
L.W.
n
=
30
(n = 1)
34.8
34.6 f 0.9
(n = 5)
36.1 f 1.0
(n = 4)
37.2 -f 0.6
(n = 3)
31.8 f 0.9
(n = 4)
31.2 f 0.6
(n = 7)
38.0
(n = 114
36.3 f 1.2
(n = 5)
KM
=
1)
n =5
50.3
(n = 1)
(n
+
49.2 2.5
(n = 3)
50.0
KS
'E.W., early wet; L.W., late wet; E.D., early dry; L.D., late dry.
*In which measurements were taken.
3Year of birth (Dresumed vear in Darentheses).
4Number of dais on which measdrements were taken (sample size).
Total number of davs
L.D.
E.D.
L.W.
L.D.
E.W.
Period2
Dec. '73Jan. '74
Aug.- Sept.
'75
Jan. '76
E.W.
Season'
n = 4
46.1 f 2.1
(n = 4)
KN
n
=
40
44.5 -f 2.2
(n = 5)
45.0 i 0.0
(n = 3)
47.0
(n = 1)
46.0 f 1.4
(n = 2)
43.8 f 1.1
(n = 4)
44.8 f 0.4
(n = 2)
41.8 f 0.4
(n = 2)
39.8 f 1.3
(n = 9)
42.0 f 0.5
(n = 7)
43.5 f 0.6
(n = 5)
SB
n=2
39.5
(n = 1)
38.0
(n = 1)
LU
n = 3
44.0
(n = 1)
38.5 f 2.1
(n = 2)
MU
n = l
21.0
(n = 1)
LJ
(196413
8.5 f 0.0
(n = 2)
KB
19743
30.5
(n = 1)
26.5 -f 1.4
7.5 i 0.0
(n = 3)
(n = 2)
29.0
8.0 f 0.4
(n = 7)
(n = 1)
8.5 f 0.0
31.0
(n = 2)
(n = 1)
32.5
12.3 -f 0.1
(n = 2)
(n = 1)
n = 7
= 16
-n
18.5
(n = 1)
MS
19663
TABLE 2. Mean body weights (kg f SD)of male chimpanzees at Mahale between December 1973 and March 1980
Feb. '76
July '77
Apg.-Oct.
77
Nov. '77Jan. '78
Feb.-Apr.
'78
May- July
E.W.
L.W.
E.D.
L.D.
'78
Sept.-Oct.
n = l
30.5
(n = 1)
WB
n=2
38.3 5 3.2
(n = 2)
ww
WT
n=6
34.5
(n = 1)
33.8 & 0.6
(n = 3)
40.5 f 0.0
(n = 2)4
'E.W., early wet; L.W., late wet; E.D., early dry; L.D., late dry.
'In which measurements were taken.
'Year of birth.
4Number of days on which measurements were taken (sample size).
'Weighed with KB.
Feh.-Mar.
'80
Total number of davs
L.W.
L.D.
E.D.
L.W.
E.W.
'78
.-
Aug.-Sept
'75
Jan. '76
L.D.
L.W.
Dec. '73Jan. '74
Feh. '74
Period'
E.W.
Season'
n = 2
32.5
(n = 1)
35.0
(n = 1)
ws
n=6
41.8 k 1.3
(n = 5)
40.3
(n = 1)
WI-ML
(male)
19723
44.6 k 1.0
(n = 6)
45.0
(n = 1)
40.0
(n = 115
47.0
(n = 1P
42.5
(n = 115
41.5
(n = 1)
42.6 f 0.8
(n = 3)
40.0
(n = 1)
37.1 k 1.2
(n = 5)
42.2 k 0.9
(n = 8)
41.5
(n = 1)
42.5
(n = 1)
n = 27 + 35
CH
n=2
32.5
(n = 1)
38.0
(n = 1)
WL
GW
n = 2
33.5
(n = 1)
37.5
(n = 1)
TABLE 3. Mean body weights (kg & SD) of female chimpanzees at Mahale between December 1973 and March 1980
n = l
30.0
(n = 1)
ND
319
BODY WEIGHT OF WILD CHIMPANZEES
TABLE 4.Mean body weights (kg k SD)o f adult common chimpanzees (Pan troglodytes schweinfurthii) from three
nonulotinna
Adult
female/
adult male
Pooulation
Mahale
Gombe
Eastern Zaire
Average of
the three
Adult males'
Adult females2
42.0 k 5.4 (n = 6)
Range: 34.3 -49.63
30.3-52.04
39.5 4.5 (n = 9)
Range: 33.6-47.33
31.8-49.54
42.3 (n = llI7
35.2 f 3.9 (n = 8)
Range: 30.0-41.83
30.0-45.54
29.8 k 2.2 (n = 6)
Range: 26.4-32.33
22.7-35.Ei4
30.0 (n = 7)7
42.8 f 2.8 (n = 3)
Range: 41.0-46.0
40.9 4.6 (n = 18)
Range: 33.6-49.6
34.3 f 5.6 (n = 9)
Range: 27.6-46.0
33.4 k 4.7 (n = 23)
Range: 26.4-46.0
+
+
(%)
Source
83.8
This study (Dec. 1973Mar. 198015
75.4
Wrangham and Smuts
(1980)6 (1970-1973)5
70.9
Pusey (1978)(July 1970Dec . 197iY5
Rahm (1967)(1963-1966)5
80.1
81.7
nonulationn
'Differences between the respective means are not significant.
'Differences between the means for Mahale and Gombe and for Gombe and eastern Zaire are significant (Mahale vs. Gombe, t =
3.041, d.f. = 12, p < 0.05; Gomhe vs. eastern Zaire, t = 3.513, d.f. = 13, p < 0.01). Difference between the means for Mahale and
eastern Zaire is not significant.
'Individual mean body weight.
4All measurements.
5Period in which measurements were taken.
'Statistical analysis of the present paper is based on the data from Wrangham and Smuts (1980).
7Means were calculated taking the second heaviest weight far each individual.
Six adult males averaged 42.0 kg and eight
adult females (excluding WI) 35.2 kg. Judging by the external appearance, however, KM
seemed to be the smallest among the adult
males of K- and M-groups. The mean body
weight for all adult males (more than 25
individuals recorded so far in the two groups)
may thus be higher to some extent than 42
kg. Our personal impressions do not suggest
such a bias for the female data.
Data on body weight of all individuals are
combined in three-month blocks in order to
see the body weight development and/or the
seasonal variation: November-January
(early wet season), February-April (late wet
season), May-July (early dry season), and
August-October (late dry season plus the beginning of the wet season) (Tables 2 and 3).
No clear-cut picture can be drawn for the
body weight development of four immature
chimpanzees or for the seasonal variation in
body weight of the other individuals because
the data were incomplete. However, it must
be pointed out that, except for GW, all chimpanzees including the two developing immatures (MS and KB) weighed between July
1977 and October 1978 showed marked body
weight reduction in the period of FebruaryApril 1978 (Tables 2 and 3) when no apparent
sign of disturbance was observed. According
to Wrangham (19751, wet season body
weights at Gombe are generally higher than
dry season, but not always. This finding is
clearly affected by the inter-annual fluctuation in food production or availability (Wrangham, 1977; Uehara, 1982; Nishida and
Uehara, 19831, although the middle of the
wet season is often one of the lean seasons
for fruits (Nishida, 1976).
Comparison of adult body weight among
three populations
Data sets on adult body weight from three
different populations are now available
within the same subspecies of wild common
chimpanzees (P t. schweinfurthii): Mahale
(6" S , 29" 40'E: this study), Gombe (4'403,
29'40'E: Pusey, 1978;Wrangham and Smuts,
1980), and eastern Zaire (1"30'-1"50'S, 28"28'30'E: Rahm, 1967) (Table 4).Adult male
data from the three populations show similar
tendencies, although the sample from eastern Zaire is represented only by three individuals. By contrast, adult female data are
not similar to one another. Not only is the
mean value of Gombe significantly lower
than Mahale and eastern Zaire, but the range
of the former population apparently differs
from the latter two populations (Table 4).No
significant difference in adult female body
320
S. UEHARA AND T. NISHIDA
weight exists between Mahale and eastern
Zaire.
With the current information, it is difficult
to draw a definite conclusion regarding the
factors causing the intra-subspecific variation in body weight described above. However, the following speculations are worth
testing in future studies.
Geographically, both Mahale and Gombe
are situated on the eastern shore of lake Tanganyika and consist of grassland, open woodland, thicket woodland, and gallery forest
(Collins and McGrew, 1985), while Rahm’s
study site (1967) is located in the lowland
rain forest of eastern Zaire. Physical features, climate, and vegetation at Mahale are
basically similar to those at Gombe, although some characters such as the rainfall
and vegetation indicate that Mahale is wetter than Gombe (Collins and McGrew, 1985).
Therefore, it is not expected that the intrasubspecific variation in female body weight
is explained solely on the basis of the environmental gradient.
Comparing the distribution of the three
populations, however, a conspicuous aspect
of Gombe emerges. The chimpanzees at
Gombe seem to have been confined to a relatively small, isolated habitat owing to human disturbance, although in 1960 there
were pockets and strips of forest connecting
the Gombe chimpanzee with the chimpanzee
population outside the national park (Goodall, 1983). At least in the main study unitgroups a t Gombe (Kasakela and Kahama
communities), immigrant females have exceeded emigrant females in number (Goodall, 1983). The effect of artificial feeding is
often thought to be the only cause for such
a n imbalance, but this does not seem to be
the case (Goodall, 1983: 51-52). Although it
is not certain, there remains a possibility
that the population density at Gombe is
increasing.
Core areas of female chimpanzees are much
narrower than those of male counterparts
(Wrangham, 1975, 1979; Hasegawa, unpublished data). Therefore, female chimpanzees
may be expected to be subject to more severe
feeding competition than are male chimpanzees. This situation may be exaggerated
when the habitat is small and becomes isolated, as in Gombe. (In such a situation, overt
competition among groups of adult males
may also become stronger.) The body weight
reduction among adult female chimpanzees
a t Gombe may be explained in this context.
ACKNOWLEDGMENTS
The field work was financed by the Ministry of Education, Science, and Culture, Japan, between 1973 and 1974 and in 1977
(Grants-in-Aid for Overseas Scientific Research to J. Itani and to T. Kano), and by the
Japan International Cooperation Agency between 1975 and 1980. The Tanzania National Scientific Research Council, the
Wildlife Division of the Ministry of Lands,
Natural Resources, and Tourism, Tanzania,
and the Serengeti Wildlife Research Institute permitted us to conduct the study and to
publish this paper. The staff at the Mahale
Mountains Wildlife Research Centre (Kasoje
Chimpanzee Research Station) supported the
research. M. Uehara, K. Kawanaka, T. Hasegawa, and R. Nyundo greatly contributed to
the collection of data in the field. H. Takasaki and two anonymous reviewers commented on a n earlier version of this paper. J.
Itani and T. Kano encouraged the study. The
preparation of this paper was financed in
part by a 1986 Research Grant from Sapporo
University to S.U. and in part by a Grant-inAid for Special Project Research on Biological Aspects of Optimal Strategy and Social
Structure from the Japan Ministry of Education, Science and Culture to T.N. To these
people and institutions, we make grateful
acknowledgment.
LITERATURE CITED
Collins, DA and McGrew, WC (1985)Chimpanzees’ (Pun
troglodytes) choice of prey among termites (Macrotermitinae) in western Tanzania. Primates 26t375-389.
Goodall, J (1983) Population dynamics during a 15 year
period in one community of free-living chimpanzees in
the Gombe National Park, Tanzania. Z. Tierpsychol.
61: 1-60.
Hiraiwa-Hasegawa, M, Hasegawa, T, and Nishida, T
(1984) Demographic study of a large-sized unit-group
of chimpanzees in the Mahale Mountains, Tanzania: A
preliminary report. Primates 25t401-413.
Jungers, WL and Susman, RL (1984) Body size and skeletal allometry in African apes. In RL Susman (ed): The
Pygmy Chimpanzee: Evolutionary Biology and Behavior. New York: Plenum Press, pp. 131-177.
Nishida, T (1968) The social group of wild chimpanzees
in the Mahali Mountains. Primates 9:167-224.
Nishida, T (1972)A note on the ecology of the red-colobus
monkeys (Colobus badius tephrosceles) living in the
Mahali Mountains. Primates 13:57-64.
Nishida, T (1976) The bark-eating habits in primates,
with special reference to their status in the diet of wild
chimpanzees. Folia Primatol. 255377-287.
Nishida, T (1979) Social structure among wild chimpanzees of the Mahale Mountains. In DA Hamburg and
ER McCown (eds): The Great Apes. Menlo Park: Benjamidcummings, pp. 72-121.
Nishida, T (1981) The World of Wild Chimpanzees. Tokyo: Chuokoron-sha. (in Japanese)
BODY WEIGHT OF WILD CHIMPANZEES
Nishida, T, Hiraiwa-Hasegawa, M, Hasegawa, T, and
Takahata, Y (1985) Group extinction and female transfer in wild chimpanzees in the Mahale National Park,
Tanzania. Z. Tierpsychol. 67:284-301.
Nishida, T and Uehara, S (1983) Natural diet of chimpanzees (Pan troglodytes schweinfurthii): Long-term record from the Mahale Mountains, Tanzania. Afr. Stud.
Monogr. 3t109-130.
Pusey, AE (1978) The physical and social development of
wild adolescent chimpanzees (Pan troglodytes schweinfurthii). Unpubl. dissertation. Stanford Univ.,
California.
Rahm, U (1967) Observations during chimpanzee captures in the Congo. In D Starck, R Schneider, and HJ
Kuhn (eds): Progress in Primatology. Stuttgart:
Fischer, pp. 195-207.
Uehara, S (1982) Seasonal changes in the techniques
321
employed by wild chimpanzees in the Mahale Mountains, Tanzania, to feed on termites (Pseudacanthe
termes spiniger). Folia Primatol. 37~44-76.
Wrangham, RW (1975) The behavioural ecology of chimpanzees in Gombe National Park, Tanzania. Unpubl.
dissertation, Univ. of Cambridge, England.
Wrangham, RW (1977) Feeding behaviour of chimpanzees in Gombe National Park, Tanzania. In TH Clutton-Brock (ed): Primate Ecology. London: Academic
Press, pp. 504-538.
Wrangham, RW (1979) On the evolution of ape social
systems, Social Science Information 18:335-368.
Wrangham, RW and Smuts, BB (1980) Sex differences in
the behavioural ecology of chimpanzees in Gombe National Park, Tanzania. J. Reprod. Fert., Suppl. 28:1331.
Документ
Категория
Без категории
Просмотров
7
Размер файла
426 Кб
Теги
mountain, parks, pan, chimpanzee, mahaleb, tanzania, schweinfurthii, weight, national, wild, body, troglodytes
1/--страниц
Пожаловаться на содержимое документа