Sharks choose “friends” based on genetic similarity and size
Washington: In a new research, a team of biologists has determined that lemon sharks choose their “friends” based on two qualities, namely, genetically similar species and size.
According to a report in Discovery News, British biologists, led by Tristan Guttridge of the University of Leeds, UK, did the research.
They looked at lemon shark groupings in the waters off of Bimini, Bahamas. The sharks congregate around this small chain of islands east of Miami, Florida.
The first shared quality that seems to connect social sharks is species.
Lemon sharks regularly interact with other genetically similar elasmobranchs, such as nurse sharks.
When given a choice, a lemon shark will therefore hang out with other lemon sharks, according to the study.
The other shared attribute among probable shark “friends” is size, although young sharks aged 0-1 years weren’t so picky.
The researchers focused on 42 juveniles aged 2-3 years old and determined they preferred to chill with similar sized sharks.
The biologists also discovered juvenile sharks would rather be in the company of other similarly sized lemon sharks than to be alone.
Perhaps mini gangs help the sharks with foraging, warding off predators, dealing with bigger bullies of their own species, or with some other aspect of survival.
The fact that these sharks are so social opens the doors to additional possibilities about their behaviour.
According to the researchers, this type of associative pattern has been linked to the evolution of cooperation and may also have implications for the flow of information through a population and social learning, adding that the sharks’ relative brain mass overlaps with that of mammals and birds.
In short, sharks are brainy.