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Adult killer whales are more likely to follow an older female when times are tough. Credit: National Oceanic and Atmospheric Administration
In many human cultures, the elderly have been respected as sources of knowledge and experience. And one non¬-human culture seems to revere its elders as well: a population of killer whales. In fact, they’re most likely to follow an older female when times are tough.
Female orcas can give birth between the ages of about 12 and 40. But unlike many other mammals, which don’t live beyond their childbearing years, female orcas can live into their 80s or 90s.
Females play a leading role in groups of orcas off the coast of Washington and British Columbia. The young may stay with their mothers for life — especially the males. And the mothers often lead these family groups.
Recent research says that’s especially true when food is scarce. The killer whales eat mainly chinook salmon. But the number and location of the salmon varies from year to year. Some years, the numbers are good, so there’s plenty to eat. Other years, though, the salmon aren’t as abundant, or they’re outside their usual territory.
Researchers looked at hundreds of hours of video of more than a hundred individual orcas. They also studied records of the numbers and locations of salmon over several decades. And they found that when the salmon were scarce, the orcas were most likely to follow older females. Years of experience may have taught the females where the fish go under different conditions. The other orcas follow them to better fishing grounds — benefitting from the knowledge and experience of the older generation.
