Newton-Fisher adds that both the above cases occurred in the same general area near
the western border of the Sonso community. In the case he observed, the female whose
infant was eaten was not a current resident member of the Sonso community and most
likely was a peripheral female from a neighbouring community to the west, the Nature
Reserve or the Nyakafunjo community. In this case there was no evidence of harm being
done to the mother. It may be that the Sonso males knew her, perhaps she was originally
from Sonso. In that case she may have emigrated and sired the infant in the neighbour-
ing community. Why she had returned to Sonso with the infant is not known; the same
question can be asked of all such cases where females move to a new community with
a new infant. The fact the infant was a male is also of interest as the majority of cases
of infanticide occur to male infants (future competitors of the resident males but also
potential allies for hunting and territorial defence).
A fourth case that we considered was an infanticide was observed on 1 August 1997.
The following is taken from notes in the BFP Events Book made by a doctoral student,
Clea Assersohn:
10.45 High levels of excitement and vocalizing within a group of 21 individuals. At 11.54 an adult
female, Kwera (KW), with her infant Kwezi (KZ) on her back, was seen carrying an infant carcass.
Males were excitedly displaying and moving. At 12.00 KW was seen without the carcass. At 12.06
the adult male Bwoya (BY) had the carcass. He sat with the carcass between his legs, not attend-
ing to it, then at 12.12 made a day nest and took the carcass into it. At 13.02 he left the nest with
the carcass still whole. At 13.11 and 13.16 he groomed the carcass, and at 13.26 held it up and
inspected it, then at 13.32 made another nest and took the carcass into it. At 14.50 the carcass fell
to the ground and BY left the nest. (Sex of this infant was not determined.)The following notes were made on the carcass when it was inspected on the ground: it
was 27 cm long, a small baby, perhaps a week or two weeks old. It had deep lacerations
through both legs to the bone. There were tooth marks on its back. Cause of death could
not be ascertained but the injuries were too severe to have been sustained simply
through being carried in the mouth. None of the Sonso resident females had given birth
recently and it was therefore concluded that this infant was that of a non-community
female.
For three other cases we have only scanty evidence. On 12 August 1997 the young
adult female Sara (SR) was seen with an (unsexed) infant not thought to be hers. The
infant was screaming. Other chimpanzees were very excited, trying to grab the infant
from her. Tinka (TK), a low ranking male, bit SR on the back apparently harassing her
to get her to release the infant. SR and other chimpanzees were screaming a lot. We do
not know the circumstances surrounding the death of this infant, nor whose it was.
On 13 December 1999 the adult male Jambo (JM) was seen carrying a recently
born male infant around until it starved to death, after which he continued to carry it for
a further two days. The incident is described by Notman and Munn (2003). Several Sonso
females were around near JM and the infant but none appeared distressed or anxious.
The infant was producing high-pitched squeals and whimpering; JM responded by
Infanticide by Sonso males 149