Fiji, Pacific Ocean – New research has found that bull sharks show a slight preference for spending time with their relatives, revealing a new aspect of their social behavior.

Scientists studied adult bull sharks at Shark Reef Marine Reserve in Fiji using genetic data and six years of observations. The research found that while most sharks were not closely related, individuals were slightly more likely to associate and socialize with relatives than unrelated sharks.

Researchers from the University of Exeter, Fiji Shark Lab and Lancaster University introduced the term “kinfluence” to describe how family relationships can influence social structure and behavior.

Lead author Natasha D. Marosi said that previous research showed bull sharks actively choose social partners based on factors such as sex, age and size. The new study revealed that family connections also play a role, although the effect is not as strong as those other factors.

The study measured shark relationships through proximity-based associations, where sharks were within one body length of each other, as well as social behaviors including parallel swimming, “lead-follow” formations and synchronized swimming.

Researchers found that family ties may contribute to these behaviors, especially among pairs of male sharks. They suggested that sharks may recognize relatives through early-life experiences when siblings and cousins spend time together in rivers and estuaries.

The findings challenge the perception of sharks as completely solitary animals, showing that bull shark social networks are shaped by a combination of family ties, sex, size and age.

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