Sharks have distinct personalities, just like humans, spiders, chimps, and many other animals. In biological terms, "personality" means consistent individual differences in behaviour across situations.

In this study, shark behaviour was documented across three situations (ranging from complex to simple environments). Some sharks preferred to swim solo (or in small groups), while others tended to form large groups, no matter the situation. Just like people, some sharks are loners, while others are social butterflies.

This result was not unexpected; it joins a growing body of research that reveals distinct personalities in individual animals of many species. These studies are interesting because they emphasize the evolutionary importance of individual differences in animal behaviour . There is a historical bias towards treating entire species as single, consistent behavioural units. This approach is useful for large, taxonomic studies which depend on more readily quantifiable traits, such as DNA or coloration; however, a more detailed approach is necessary for behavioural ecology.

By better understanding personality difference in animals, we may be able to understand and predict animal response to climate change and human expansion. For example, perhaps social butterfly sharks are better equipped to react, respond to, and survive the effects of industrialization, the fishing industry, and human expansion. (Living in groups can confer many advantages; e.g., it can help with migration, avoiding predators, and hunting). If this is the case, we will observe a subtle shift of species makeup over time; sharks with certain personalities will have a leg up on their solitary compatriots.

In other words, we may be heading for a future where sharks roam the water in schools to an even greater extent than they already do. Sharknado 3, anyone?