Sharks Have Personality Traits
Is there such a thing as a friendly shark? Most of us would feel happy ascribing ‘personalities’ to our pets, but sharks seem to be the perfect cold-blooded predator of the deep. However, recent research into shark ‘personalities’ has produced evidence that there is more to these ferocious predators then meets the eye?
Recent studies have examined the behaviour of a range of animals, from fish to spiders, and in every case there is evidence that individuals react in unique ways, which can be classified as different ‘personalities’. A paper published earlier this week by the University of Exeter focused on spotted catsharks. This species is ideal for this type of behavioural experiment because they are common to British waters, easy to keep in captivity, and are usually gregarious, gathering in small groups to rest on the seabed.
To test their behaviour the researchers divided the sharks into ten groups and placed them in large tanks containing three different types of environment which varied in their complexity. This meant some parts of the tank had gravel plains whilst some had rocks and other features. The size of the groups often varied between these environments but each time those individual sharks which preferred large groups continued to seek out companionship, while the sharks which preferred solitude swam away to camouflage themselves separately. This led to the rough distinction between sharks which were ‘sociable’ and others which were ‘anti-social’. Importantly these traits did not vary depending on the type of terrain, so individuals were not simply adapting their behaviour to best suit the environment, but were instead demonstrating a genuine, unique preference.
This isn’t the first attempt to test the personality of sharks however. In 2012 the Bimini Sharklab started a long-term project aimed at Lemon Sharks. They tested 121 juvenile Lemon Sharks of which 81 underwent later retesting. Their results are preliminary as the project is still ongoing, but it seems that lemon sharks also demonstrate different individual social tendencies, which are repeated over time and space. This suggests that personality may be more widely spread within shark species then previously realised.
Photo Source: Wikimedia Commons