New research reveals that bull sharks form social relationships with specific "friends," challenging the long-standing belief that these predators live mostly solitary lives.

The study -- conducted at the Shark Reef Marine Reserve in Fiji -- found that bull sharks do not simply mix randomly. Instead, they display "active social preferences," choosing certain individuals to spend time with while avoiding others.

The work involved researchers from the University of Exeter, University of Lancaster, Fiji Shark Lab, and Beqa Adventure Divers.

"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," said lead author Natasha D.…