Geology Reference
In-Depth Information
ies found among the red colobus. The different
subspecies have either retained their ancestral
behaviour pattens, or have adapted convergently
or divergently in response to similar or different
ecological condiions experienced over evoluion-
ary ime. Such specialisaions and changes,
illustrated here by the red colobus, are among the
evoluionary mechanisms through which new spe-
cies may evolve.
Of the 14 subspecies of red colobus five are
classified as rare and endangered (IUCN, 1966,
1986); these include all three subspecies found in
eastern Africa. The forest habitats where these
monkeys are found are disappearing owing to
human destrucive aciviies such as agriculture,
tree felling, settlement, industry and fire (Marsh,
1978a, 1985; Rodgers, 1981 and Chapter 14;
Struhsaker, 1981; Mturi, 1983, 1991 and per-
sonal observations; Wasser
&
Lovett, Chapter l;
Wasser, Chapter 13). Therefore to protect these
red colobus subspecies and other fauna and flora
there is a great need to protect the forests in
easten Africa. Hopefully, incenive to protect
these areas can be facilitated by increasing public
awareness that forests provide vital water catch-
ment to the country's predominantly arid land.
more mature leaves than those in habitats of low
tree diversity.
The red colobus showed similar group com-
posiion, with few excepions, forming multi-male
and fe male groups except the Tana red colobus.
Solitary individuals, adult and subadult males
(and, in the Gambia red colobus, adult and
subadult females) also occurred. Groups of red
colobus had more adult and subadult females
than respecive males. Among the subspecies of
red colobus there was variation in age and sex of
individuals that transferred between groups.
Variation in intra- and inter-group relations
and ranging pattens was observed both between
and within subspecies of red colobus. In the
Zanzibar, Kibale and Gombe red colobus inra-
group relaions were mostly peaceul; in the Tana
and Gambia red colobus adult and subadult males
were generally hosile to each other. Inter-group
relaions varied from tolerant to aggressive in
Zanzibar, Kibale and Gambia red colobus; but
were basically aggressive in Tana red colobus.
The Zanzibar, Kibale and Gambia red colobus
exhibited extensive range overlap; Gombe, Sene-
gal and Tana red colobus had largely or wholly
exclusive use of their ranges. All red colobus
subspecies showed polyspecific associaions with
primate species sympatric to them.
The comparison shows how habitat and phylo-
geny interact to yield the differences and similari-
ties observed among the red colobus. Such
specialisations and changes among the red col-
obus demonstrate the evolutionary mechanisms
through which new species may evolve.
All the three subspecies of red colobus in
eastern Africa are rare and endangered. There is,
therefore, an urgent need to conserve them and
other species by protecing the forests of eastern
Africa.
Summay
Food habits, group composition, ranging patterns,
intraspecific relaions and primate polyspeciic
associations of the Zanzibar red colobus monkey
Colobus badius kirkii
are described and compared
with other subspecies of red colobus monkeys
(.
b. tphrosceles in Kibale, Uganda and Gombe,
Tanzania; . b. ruamitratus in Tana, Kenya; . b.
goronorum in Mwanihana, Tanzania; . b. tem-
minckii in Fathala, Senegal and Abuko, Gambia).
Food habits of the red colobus subspecies were
very similar with only few excepions. They used a
variety of plant species and plant parts, and were
very selecive in their eeding. Feeding on animal
matter and drinking of free water were
infrequent. However, the Mwanihana red colobus
specialised on leaf peioles of various species
while charcoal eating was unique to the Zanzibar
red colobus. The subspecies in habitats with high
tree diversity had more diverse diet and used
Acknowledgements
I thank the Office of Ministry of Natural
Resources and Tourism and the Deparment of
Forestry who permitted field work in Zanzibar,
and to the University of Dar es Salaam for
financial support. Ors K. Homewood, J. I. Pol-
lock, A. M. Nikundiwe, W. A. Rodgers and A. H.
Omari gave advice and encouragement through-
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