London, November 12 In a new research, scientists have found out that leatherback turtles prefer to use their right rear flipper rather than their left when laying eggs.
According to a report by BBC News, the result is the first time a species of turtle has found to prefer one limb over another.
The discovery adds to growing evidence that even lower vertebrates prefer to use one side of the body more often.
Such preference is known by scientists as a "lateralised functional behaviour", and it usually indicates that an animal's brain function is also lateralised, with one side of the brain dominating control of certain tasks.
This asymmetry is called 'flipperedness' in the use of the leatherback's flipper because 'handedness' is used in primates, 'footedness' in birds and 'pawedness' in rodents.
Studies on relatively small numbers of reptiles have shown that some species display lateralised behaviour.
For example, cottonmouth snakes tend to prefer to coil one way more than the other, while upturned Mediterranean tortoises prefer to right their bodies to one side.
But, a team of US-based researchers led by Annette Sieg of Drexel University in Philadelphia, Pennsylvania investigated whether such a similar preference occurs across a large wild population of leatherback turtles.
When female leatherbacks come ashore to lay their eggs, they clear out an chamber for the eggs using repeated movements of their rear flippers.
Then as they lay their eggs, they move one rear flipper back over the opening from which the eggs emerge, called the cloaca, obscuring it, perhaps to prevent the eggs being spotted by predators.
The turtles do this spontaneously, and it is the only time when leatherbacks use a single flipper to perform a particular task.
Dr Sieg and her colleagues observed flipper use among 361 females laying at the Playa Grande rookery on the northern Pacific Coast of Costa Rica.
Over five years, they watched as these females laid eggs on 1889 occasions.
Overall, the turtles preferred to use their right hind flippers 54 percent of the time.
Although the preference is subtle, it is statistically significant, revealing a bias in flipper use at the population level.
The study is the first to show a limb preference among Testudinata, the group that comprises turtles and tortoises, and is the largest multi-year study of any spontaneous behaviour in a lower vertebrate. (ANI)
