Whitehead, H. and L. Rendell. 2004. Movements, habitat use and
feeding success of cultural clans of South Pacific sperm whales
Journal of Animal Ecology 73: 190-196
This paper is available at:
<a href="http://is.dal.ca/~whitelab/hw/JAE_798.pdf";
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ABSTRACT:
1. The population of sperm whales (Physeter macrocephalus) in
the South Pacific is divided into at least five sympatric vocal clans
that almost certainly reflect cultural variation.
2. We investigated differences in movements and feeding success
of groups from different clans off the Galápagos Islands and
northern Chile, using data from 87 days spent tracking
groups of known clan.
3. Groups from different clans showed different use of habitat and
movement patterns. Off the Galápagos Islands, 'Plus-one' clan
groups moved in relatively straight lines while 'Regular' clan groups
had more convoluted tracks and a more inshore distribution,
patterns which were consistent across years.
4. Groups from different clans had different defecation rates,
indicating between-clan variation in feeding success. Off the
Galápagos Islands, 'Plus-one' clan groups were more successful in
the depauperate ENSO ('El Niño/Southern Oscillation') conditions
of 1987. However, in the cooler conditions of 1989, groups of the
'Regular' clan had much higher feeding success than those of the
'Plus-one' clan.
5. Thus we suggest that cultural inheritance in sperm whales
incorporates foraging strategy as well as vocal patterns, and that
clan membership has fitness consequences.
6. That clans seem differentially affected by altered climate
conditions has implications for the effects of global warming on
sperm whales.
7. The results also support the hypothesis that culturally
determined differences in fitness may have affected genetic
evolution through the process of cultural hitchhiking.
Key-words: Chile, cultural hitchhiking, ENSO, Galápagos, Physeter.
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