© Photo by Francois Gohier/VWPics/Alamy Stock Photo
The finding that male sperm whales have male friends bucks the long-standing assumption about sperm whale behavior.
Scientists have long believed that male sperm whales are among nature's loneliest creatures. Unlike female sperm whales, which spend their entire lives living in matrilineal societies among their female kin, males get kicked out of their mothers' pods once they reach sexual maturity and then spend the majority of their lives alone.
Or so we thought.
A new study has found evidence that male sperm whales can develop strong, long-lasting bonds, forming friendships with other males that can last for at least five years.
The findings of this landmark study are based on 12 years of observations conducted by researchers working in the Nemuro Strait, a narrow stretch of water sandwiched between Hokkaido, in northern Japan, and the southernmost Kuril Island. The strait is visited by hundreds of migrating sperm whales each year. Although male sperm whales have previously been observed feeding together, and even stranding themselves in all-male groups of unrelated individuals, no one knew what was driving them to do so.
To find out, researchers led by Hayao Kobayashi, a sociobiologist at Nagasaki University in Japan, spent thousands of hours aboard whale watching boats photographing 226 male sperm whales and listening in on their conversations using hydrophones.
"It takes a steady effort, extensive data sets, and patience to reveal the ecology of long-life animals," says Kobayashi. Although the data collection was arduous, it let the researchers determine which whales hung out together, and for how long.
