Causes of mortality in M group chimpanzees during 19 years (1980-1999)
Causes of mortality	N	Memo
Disease	56
Senescence	28
Within-species aggression	18	17 victims were infants
Predation	at least 6	Occurred only 1989
Maternal death	4
Twin birth	2	Twin birth was observed only once
Snares	1
Unknown	91
Total	207
Source:
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[74] Hamai M., Nishida T., Takasaki H. & Turner L.A. (1992) New records of within-group infanticide and cannibalism in wild chimpanzees. Primates 33: 151-162
[75] Matsumoto-Oda A. (1995) First record of a twin birth in chimpanzees of Mahale Mountain National Park, Tanzania. African Study Monographs 16: 159-164