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Brief report Chimpanzees tools and termites New record from Gabon.

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American Journal of Primatology 5:171-174 (1983)
BRIEF REPORT
Chimpanzees, Tools, and Termites: New Record
From Gabon
W.C. McGREW' A N D M.E. ROGERS'
'Department ofPsychology, University of Stirling, and 'Department
Edinburgh, Scotland
of
Zoology, University of
Wild chimpanzees (Pun troglodytes) in northeastern Gabon use tools made
of vegetation to obtain termites (Macrotermes Znobilis) for food. They mostly
use probes in termite fishing, as recorded elsewhere in eastern and far
western Africa. This is the first record of termite fishing by the central west
African race of chimpanzees. There are signs that they also use stouter
tools, perhaps to perforate the mounds of the termites. These new findings
further complicate the status of material culture in this species of ape in
nature.
Key words: tool use, chimpanzee, termite, Pan troglodytes, Macrotermes, culture
INTRODUCTION
Chimpanzees in the wild use tools made of vegetation to obtain termites for
food. Since this was first found by Goodall [1963] a t Gombe in Tanzania, it has been
recorded a t eight other sites in Africa [McGrew et al, 1979; Nishida & Uehara,
19801. This note describes a newly discovered case of this tool use, at Belinga in
northeastern Gabon. This has important ethnological implications; for example, it
is the first report of termite fishing in primary forest, and it may be the first instance
of one population of apes using tools for both fishing and perforating.
METHODS
We spent 7 weeks (15 July-31 August, 1981) collecting ecological data on chimpanzees (Pun t. troglodytes) and gorillas (GoriZZa g. goriZZa) a t Belinga (1'06' N,
13"12' El. Most of the area is primary rain forest, although the annual rainfall is
only about 1,700 mm [Hladik, 19781. Over this period we spent 276 h searching for
apes or their signs. The apes of the area are unhabituated to humans, and the
vegetation is dense, so it is very difficult to obtain direct sightings. On 3 days spent
following chimpanzees, we found tools left by them on the surfaces of the subterranean nests of Macrotermes ?nobilis.
Received July 24, 1982; accepted May 23, 1983.
Address reprint requests to W.C. McGrew, Department of Psychology, University of Stirling, Stirling,
FK9 4LA. Scotland.
0 1983 Alan R. Liss, Inc.
172
McGrew and Rogers
As we never saw chimpanzees using these objects, how can we say that they
were tools used by chimpanzees? This question assumes even greater importance as
the gorillas of the area regularly eat termites [Tutin and Fernandez, in press]. In
fact, the evidence is circumstantial, and a previous paper gave eight criteria to be
met in considering the validity of such data [McGrew et al, 1979, pp 189-1901. Table
I lists these criteria and their definitions. The objects we collected meet seven of the
eight criteria with only the year-to-year reliability of the data yet to be tested.
Perhaps the crucial criterion is that of close proximity to chimpanzees. On 1 August
we tracked and intermittently sighted a group of chimpanzees for almost 4 h.
Midway through this period, we found fresh signs of tool use only minutes after
chimpanzees had passed that way. There was no sign of gorillas in the area a t the
time. One tool was found in situ-ie, inserted into the soil surface of a termites’ nest.
The possibility of confusion with traces of gorilla activity is further reduced
because the two species of ape feed on different species of termites [Tutin and
Fernandez, in press]. Faecal samples show that gorillas at Belinga eat Cubitermes
sp., a smaller type of termite which builds tiered, earthen nests above the ground,
usually against the trunks of large trees. There are no records of chimpanzees eating
this genus, just as there are no records of gorillas eating Macrotermes. Gorillas have
not been seen to use tools to obtain the insects, but instead appear to break open the
nests by hand.
RESULTS
We found 30 tools. Nine additional artifacts were discarded as doubtful, and
fragments of tools resulting from manufacture were ignored. Twenty-eight of the
tools were fishing probes, and all but one of these (made of a liana) were made of
twigs stripped of leaves and twiglets. None of the tools were peeled of bark. Sixteen
tools were bent or frayed from use a t their distal ends; only five of the tools showed
such signs of wear at the proximal ends. (See Table 11).
TABLE I. Criteria for Evaluating Circumstantial Evidence of Fishing For
Termites by Chimpanzees
1. Alteration
2. Use
3. Site
4. Season
5. Coincidence
6. Association
7. Near-Miss
8. Persistence
Objects are unnaturally modified-eg, peeled of
bark, stripped of leaves, etc.
Objects show signs of wear-eg, frayed from
insertion, bitten by termites, etc.
Objects found only on termite mounds.
Objects found only when mound’s surface is
vulnerable to probing.
Objects found only at mounds of one species of
termites, and subterranean forms of only that
species found in the feces of chimpanzees at that
time.
Objects found in association with other signs of
chimpanzees-eg, footprints, hairs, feces.
Objects found in close proximity to chimpanzees
seen or heard by observers.
Criteria 1-7 hold over more than one annual
cycle.
Chimpanzee Termite-Fishing in Gabon
173
TABLE 11. Characteristics of Fishing Probes Used by Chimpanzeesat Belinga, Gabon
Proximal
diameter
Length
N
-
=
23a
N
25
0.4 cm
Median = 0.4 cm
=
x = 37.8 cm
x
Median = 38 cm
Range = 17-59 cm
Range = 0.3-0.9 cm
=
Distal
diameter
N = 23a
x = 0.3 cm
Median = 0.3 cm
Range = 0.15-0.6 cm
Signs of wear
= 25
9-Frayed
6-Bent
5 Frayed and bent
5-Neither
N
aTwo of the tools were unfinished-ie. not modified at the distal end.
The other two tools were very different, being stout sticks. They were longer (68
and 76 cm) and thicker at both proximal (1.7 and 1.8 cm) and distal (1.4 and 1.6 cm)
ends. They too were stripped of leaves and twigs.
Only four sources of raw materials could be identified: Scaphopetalum thonneri
(Sterculiaceae), Calpocalyx sp. (Mimosaceae), Drypetes sp. (Euphorbiaceae), and a
species of Tiliaceae.
DISCUSSION
That another population of wild chimpanzees should be found to use tools to
obtain termites is not surprising. This is the first record from Gabon, but Hladik
[1973] noted that chimpanzees that had been transported and provisioned but which
were free-ranging near Makokou (about 100 km southwest of Belinga) ate several
other types of termites: Nasutitermes, Microterotermes, Procubitermes, etc. They did
so without tools, however and ignored Macrotermes spp.
The nearest other records of tool use to obtain termites come from Equatorial
Guinea (formerly Rio Muni). There chimpanzees used sticks as perforating tools to
break open the mounds of M. rnuelleri and M. lilljeborgi [Jones & Sabater Pi, 19693.
However, only two of the tools found at Belinga resembled the sticks found by Jones
and Sabater Pi, and we found no fresh evidence of digging a t the nests of termites.
It may be significant that, unlike M. muelleri, which builds 1-2 m high, mamillated
mounds, the earthen dome over the underground nest of M. nobilis is low, flat, and
spread out [Ruelle, 1970, p 4191. Perforating and breaking up the latter type of nest
would seem to be a n inefficient way of extracting termites from it, because excavation would be required.
The other tools closely resembled the fishing probes found at sites in eastern
and far western Africa [McGrew et al, 19791. This is the first record of their use by
the central west African race of chimpanzees. Also, all other cases of termite fishing
come from chimpanzees living in savanna, woodland, or mixed forest-woodland sites
with lower annual rainfall.
There is no other evidence of such tool use from studies of forest-living chimpanzees [eg, Ghiglieri, 19791. However, work in Tanzania [Nishida & Uehara, 1980;
Uehara, 19821 suggests that chimpanzees in wetter habitats seem to use tools less
than those living in drier areas.
McGrew et a1 [1979] proposed hypotheses about the cultural origins of tool use
by chimpanzees to obtain termites. We hypothesised three separate inventions of the
custom, with two of these being for fishing in northern Guinea and in western
Tanzania, and one being for perforation in Rio Muni or Cameroon. We proposed four
ways in which this hypothesis could be falsified. If both fishing and perforation are
used in Gabon (and possibly in Tanzania also), the the two methods of obtaining
174
McGrew and Rogers
termites cannot be simply correlated with differences in habitat and may not have
been invented separately. Much more systematic study is needed, but it seems likely
that the material culture of chimpanzees will not be explained simply in terms of
environmental constraints.
CONCLUSIONS
1. Wild chimpanzees in Gabon use slender probes to fish for termites.
2. They may also use stouter sticks to perforate or excavate termite mounds.
ACKNOWLEDGMENTS
We thank C. Tutin and M. Fernandez for essential help in the field, P. Hecketsweiler and A. Moungazi for identification of plants, A. Collins and T. Nishida for
critical comments on the manuscript, L.S.B. Leakey Trust and the Internal Research
Fund of the University of Stirling for financial aid, and the Centre International de
Recherches Medicales de Franceville and L’Institut de Recherche sur 1’Ecologie
Tropicale for sponsorship in Gabon.
REFERENCES
Ghiglieri, M.P. THE SOCIOECOLOGY OF
CHIMPANZEES IN KIBALE FOREST,
UGANDA. Ph.D. thesis, University of California, Davis, 1979.
Goodall, J. My life among wild chimpanzees.
NATIONAL GEOGRAPHIC 124(2):272308,1963.
Hladik, A. Phenology of leaf production in
rain forest of Gabon: Distribution and composition of food for folivores, pp 51-71 in
THE ECOLOGY OF ARBOREAL FOLIVORES. G.G. Montgomery, ed. Washington, Smithsonian Institution Press, 1978.
Hladik, M. Alimentation et activite d’un
groupe de chimpanzes reintroduits en foret
Gabonaise. LA TERRE ET LA VIE 27:343413, 1973.
Jones, C; Sabater Pi, J. Sticks used by chimuanzees in Rio Muni. West Africa. NAh J R E 223:lOO-101,1969,
McGrew, W.C.; Tutin, C.E.G.; Baldwin, P.J.
Chimpanzees, tools, and termites: Cross cultural comparisons of Senegal, Tanzania, and
Rio Muni. MAN 14:185-214, 1979.
Nishida, T.: Uehara, S. Chimpanzee, tools,
and termites: Another example from Tanzania. CURRENT ANTHROPOLOGY 21:
671-672,1980.
Ruelle. J.E. A revision of the termites of the
genus Macrotermes from the Ethiopian region (Isoptera: Termitidae). BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY), ENTOMOLOGICAL SERIES 24:
365-444,1970.
Tutin, C.E.G.; Fernandez, M. Gorillas feeding on termites in Gabon, West Africa.
JOURNAL OF MAMMALOGY (in press).
Uehara, S. Seasonal changes in the techniques employed by wild chimpanzees in
the Mahale Mountains, Tanzania, to feed on
termites (Pseudacanthotermes spiniger).
FOLIA PRIMATOLOGICA 37:44-76,1982.
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