Dolphins form social cliques and share hunting secrets, study finds
A scientific study conducted over two decades has found that wild bottlenose dolphins form social cliques and share specific, personalized information, including how to use natural objects as tools.
The Telegraph reports that these closed communities of dolphins keep their knowledge hidden from those outside their social circles, challenging previously held beliefs that "inclusive inheritability" is limited to humans.
The study results, which were published in the journal Nature Communications, was led by researchers from Georgetown University who monitored the behavior of dolphins in Shark Bay, Australia, over a 22-year period.
Specifically, the researchers followed a group of 36 dolphins that used sea sponges as tools to protect their noses while hunting. The results were compared with 69 other dolphins from the same location that did not pick up the sponging behavior.
"Homophily (the tendency to associate with similar others) based on tool-using status was evident in every analysis, although maternal kinship, sex and location also contributed to social preference," lead researcher Janet Mann writes in the study's findings.
"Female spongers were more cliquish and preferentially associated with other spongers over non-spongers. Like humans who preferentially associate with others who share their subculture, tool-using dolphins prefer others like themselves, strongly suggesting that sponge tool-use is a cultural behavior."
The researchers suggest that social behavior among certain animals may actually be learned, as opposed to simply passed down through genetic traits.
"Recently, many biologists are moving beyond genetic inheritance to examine the processes involved in inclusive heritability, which includes culture," Mann wrote.
"We sometimes think that traits such as culture are exclusively human, but a growing body of literature proves otherwise.