Programme  Poster session 2  abstract 132

Our cousins chimpanzees and baboons face global warming by digging wells to filtrate drinking water

Author(s): G. Galat, A. Galat-Luong, G. Nizinski
IRD UR 60 CLIFA. BP 64501. 34394 Montpellier cedex. France. Tel 33467636961. Fax 33467412138.

Keyword(s): Increasing dryness, Drinking water, Filtrated water, Wild life, Chimpanzees, Baboons

Article: abs132_article.pdf
Poster: abs132_poster.pdf
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Session: Poster session 2
AbstractIntroduction. Surface water is an essential source of life for mammals

and higher vertebrates. Global warming and dryness restrict available water resources. In the African Sudanese

climate, an annual rainfall deficit period, up to 350mm, began in the 1970’. Objective. How do Chimpanzees living in

dry habitats face increasing dryness as water pools dry at the end of the dry season? Methods. In 1975, 1976, and

from 1988 to 1999, we followed groups of chimpanzees and baboons living inside and outside the Niokolo Koba

national Park in the Kédougou department, Senegal, and recorded water related behaviors and indices. Additionally,

comparative blind tests of water samples drink ability were made. Results. In contrast with the 1975-1994 surveys,

those carried in the 1995-1999 period revealed that chimpanzees and baboons dig wells in river basins during the

dry season. The wells are hand dug holes of 20 to 40 cm depth, localized in fine sand zones less than 2m far from

stagnant water puddles. The water in the wells is therefore filtrated by the surrounding sand. Indices of animals

access to water were only found around the wells dug in the sand, not near the stagnant water puddles. The water of

the wells was clear and limpid, contrasting with the stagnant water of the natural puddles. Some wells dug by

chimpanzees were dug with wood sticks used as “tools”. Results of comparative bacteriological analyses show that

pathogenic germs characteristic of stagnant putrid water were present in the natural puddle water and made water

unsuitable for consumption, but were absent in the wells. The water of the wells contained only pathogenic germs

typical of mammal species which came to drink there, indicating that the chimpanzees have contaminated the water

with their own germs. Discussion. Some mammal species like warthogs and antelopes dig for water in the bottom of

dried pools as the water vanishes in the dry season. Although water is still available as stagnant putrid water pools,

chimpanzees and baboons dig holes in the sand nearby the stagnant water pools and get clear, limpid, filtrated water

without pathogenic germs, except for germs that probably came from the primates themselves. Conclusion. Among

the Chimpanzees populations studied on the long term in Africa, the Senegalese one lives in a very hot and dry

habitat and is the first one recorded, in 1995, to filtrate water. This behaviour has then been observed in other sites

like in Uganda, were it has been recorded from 1997. Digging wells in order to get filtrated water is a new cultural

behavior. It appeared recently independently in different Chimpanzees populations, as an adaptation to face a long

increase of dryness period. Acknowledgements. National Parks of Sénégal. Grants ORSTOM, IRD, DDR.

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