Shark brains similar to humans
Shark's brains share several common features with those of humans.
Although sharks were previously thought to have relatively simple brains, the researchers have shown that sharks and other cartilaginous fishes have a battery of highly developed sensory systems and relatively large brains.
Sharks possess brain-to-body mass ratios that are similar to mammals and birds and have exhibited apparent curiosity and behaviour resembling play in the wild
The parallels are outlined in several papers published in a special edition of the journal Brain, Behavior and Evolution.
Though once thought to have empirically simple brains, cartilaginous fishes possess a battery of highly developed sensory systems, a complex range of innate behaviours, and relatively enlarged and complex brains, which, unlike many other vertebrate systems, continue to grow throughout life.
Dr Kara Yopak from University of Western Australia's (UWA) Oceans Institute said the studies suggested people may have more in common with sharks than previously thought.
Another recent study suggests that the cerebellum - which appeared first in early sharks - is an important evolutionary advancement that has paved the way for some aspects of higher neural function in vertebrates, including humans, Dr Kara adds.
Despite broad divergence, there are a number of common features of the brain that evolved at least as early as cartilaginous fishes and persist across all vertebrates.