Bull sharks, often labeled as aggressive predators responsible for a significant number of human attacks, exhibit surprisingly complex social behavior. New research reveals that these solitary sharks form deliberate friendships, choosing specific individuals to associate with over others. The study, published in Animal Behaviour, challenges the traditional view of sharks as purely instinct-driven hunters.
The Discovery of Shark Social Bonds
For six years, researchers from the University of Exeter, the University of Lancaster, Fiji Shark Lab, and Beqa Adventure Divers monitored 184 bull sharks at the Shark Reef Marine Reserve in Fiji. The sharks weren’t just swimming randomly; they actively selected companions, demonstrating preferences in their interactions. This behavior mirrors human social patterns: forming close bonds with some while avoiding others.
“We cultivate a range of social relationships, but also avoid people. Bull sharks do similar things,” explains Natasha D. Marosi, a study co-author and founder of Fiji Shark Lab.
Researchers tracked two types of interactions: broad-scale associations (sharks remaining within one body length) and fine-scale interactions (leading, following, or parallel swimming). The findings confirm that adult sharks form consistent social ties, often with individuals of similar size.
Gender and Age Dynamics in Shark Society
Interestingly, sharks of both sexes showed a preference for socializing with females. However, males had a higher average number of social connections, likely because they are smaller and benefit from integrating into larger groups to avoid aggression from dominant females.
The most socially connected sharks were adults in their prime. Older, post-reproductive sharks and younger, sub-adults were less integrated into the network. Sub-adults, still developing, often occupy different habitats, but bolder individuals have begun forming ties with adult sharks. These older sharks may act as gatekeepers, helping younger ones integrate into the social network and learn from more experienced individuals.
Why This Matters
Understanding shark social dynamics isn’t just an academic exercise. Sharks, like many animals, likely benefit from social behavior—learning new skills, finding food, avoiding conflicts, and even identifying mates. This knowledge can inform marine policy and conservation efforts. The Fiji Shark Lab is already collaborating with the Fiji Ministry of Fisheries to use these findings to protect shark populations.
“Contrary to commonly held perceptions, sharks have rich and complex social lives,” notes Darren Croft, a study co-author.
Protecting these animals requires recognizing their intelligence and social needs, not just their predatory reputation. Sharks need their friends to survive in the ocean, and they need human allies to protect their environment.
