by
Mary E. Allen and Mark L. Kuhlmann
Department of Biology
Hartwick College, Oneonta, NY
All the evidence collected by Estes and his coworkers points to killer whales as the cause of the decline in sea otters: the increase in observed killer whale attacks on sea otters, the differences in sea otter survival and population trends at the two locations on Adak Island (Figures 3 and 4), and the energetics data (Table 1). Yet prior to the 1990s, killer whales and sea otters had co-existed peacefully for decades. What do you think has caused the killer whales to start eating sea otters? Discuss this question with your group and develop some working hypotheses to share with the class.
Originally published at http://www.sciencecases.org/sea_otters/sea_otters3.asp
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