VOL. 52, NO. 3 (SEPTEMBER 1999) P. 307–310
Infanticide and Cannibalism of Juvenile Polar Bears (
Ursus maritimus)
in Svalbard
A.E. DEROCHER
1 and Ø. WIIG2
(
Received 29 January 1999; accepted in revised form 9 June 1999)
Intraspecific predation, infanticide, and cannibalism
have been reported in polar bears
(Belikov et al., 1977;
Hansson and Thomassen, 1983; Larsen, 1985; Lunn and
Stenhouse, 1985; Taylor et al., 1985). However, some of
the instances have followed human activities such as
harvest or immobilization (Taylor et al., 1985). Regardless,
intraspecific predation has been suggested as a regulating
feature of ursid populations (e.g., McCullough,
1981; Young and Ruff, 1982; Larsen and Kjos-Hanssen,
1983; Stringham, 1983; Taylor et al., 1985).
Five main reasons for infanticide have been proposed:
exploitation of young as an energy source, competition for
resources, sexual selection, parental manipulation of progeny,
and social pathology (Hrdy and Hausfater, 1984). We
cannot assess the possible role of competition for resources
or social pathology. In neither observation was the
mother responsible for the infanticide; therefore, maternal
manipulation of the offspring was not involved.
Polar bear cubs weighing a few kilograms are a very
small energy source for an adult polar bear that normally
feeds on ringed seals (
Phoca hispida) weighing up to 60 kg
and bearded seals (
Erignathus barbatus) weighing up to
several hundred kilograms (Stirling and Archibald, 1977).
There is speculation that adult males may obtain a
breeding opportunity with adult females if they kill their
dependent offspring and the female becomes available for
breeding (Hayssen, 1984; Hrdy and Hausfater, 1984).
ACKNOWLEDGEMENTS
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