Turns Out Bull Sharks Have Best Friends — And They Actively Avoid Sharks They Don’t Like

Did you know a shark can have a favorite swimming buddy? New research says bull sharks do — and they’re a lot pickier about their company than anyone gave them credit for.

Bull sharks have a reputation as solitary, no-nonsense hunters. A six-year study at Fiji’s Shark Reef Marine Reserve just upended that entirely. Researchers tracked 184 individual bull sharks and found that instead of mixing together at random, these animals show real, consistent “active social preferences” — they choose who to swim near, and who to avoid.

How they figured this out: The team, led by Natasha D. Marosi of the University of Exeter and Fiji Shark Lab, logged more than a thousand social interactions over the six years — behaviors like swimming in parallel, following one another, or approaching and then turning back. If bull sharks were truly loners bumping into each other by chance, those patterns should look random. They didn’t.

“As humans, we cultivate a range of social relationships — from casual acquaintances to our best friends, but we also actively avoid certain people — and these bull sharks are doing similar things,” Marosi said.

Some genuinely charming patterns emerged. Female sharks tended to cluster tightly with other females, while males more often sought out female company. Since male bull sharks are physically smaller than females, researchers think staying socially connected may actually offer some protection from aggressive run-ins with bigger sharks. A follow-up study even found that kinship plays a subtle role too, layering family ties on top of size, sex, and age preferences to shape the group’s social web.

“Contrary to commonly held perceptions of sharks, our study shows they have relatively rich and complex social lives,” said Professor Darren Croft of Exeter’s Centre for Research in Animal Behaviour.

Why it matters: Bull sharks join a growing list of species — including reef sharks and lemon sharks — where scientists are finding real evidence of social bonds, not just aggregation around food or safety. It’s one more reason to rethink the “mindless hunter” reputation sharks have carried for decades, and a reminder that even animals we assume we understand can still surprise us.

Next time someone tells you sharks are loners, tell them about Chunky and Lady Lazarus — two bull sharks the researchers watched choose each other, again and again.

Sources : ECO Magazine ,physical.org