According to the CNRS, about 90% of humans are right-handed. We are talking about lateralitylinked to cerebral asymmetry, that is to say to differences in functioning and anatomy between the cerebral hemispheres. In other words, the left side controls your right hand and vice versa, and your hand preference predicts some of the activity that takes place in each half of the brain.
But if for many years, scientists thought that laterality was a particularity of humans, this is not the case. According to a growing body of research, many animals have a favorite hand, limb, or even tentacle. Even more surprising, this is linked to fascinating evolutionary and neurological mechanisms. And good news: there is an easy way to do the test at home, with your pet. The British magazines BBC Science Focus and the American Discover Magazine tell us more.
Among our cousins the great apes, the majority show a preference for the right hand, according to William Hopkins, director and president of the Keeling Center for Comparative Medicine and Research at the University of Texas (United States). For example, when measuring behaviors such as which hand they use for throwing, chimpanzees and other great apes show a 65-70% predominance in favor of the right hand. And they are not the only ones. Like most humans, walruses often prefer their right fin. Even single-celled organisms without a brain can turn right more often than left.
If scientists believe that handedness has its origins in brain asymmetry, this preference could also be influenced by evolution. According to the theory of the postural origin of the hand, early primates lived in trees and used their dominant left hand to grasp food and branches, while holding the tree with their right hand. Then, as they adapted to life on the ground, they began to use their right hand more, which became dominant over time. However, this theory has its detractors, who point out that some primates do not follow these rules, such as Brazza’s monkeys or orangutans.
A tip to know
Other animals also have their preferences. Glossy black cockatoos hold seed cones with their left paw and red-necked wallabies prefer to use their right paw to catch food. As for octopuses, despite the large number of limbs available, they still seem to have preferences when it comes to tentacle use, but this appears to be determined at the individual level.
It’s unlikely that you have an octopus in an aquarium to verify our claims at home, but rest assured: if you are the happy owner of a cat or dog, you can test this quite simply. Place a treat in a narrow, empty container and see which paw they use to retrieve it.
Many animals are ambilateral (the non-human equivalent of ambidexterity) and sometimes these preferences are gender biased. If the science is correct, most males will favor their left paw, while most females will favor their right paw. Come on, it’s up to you, but keep in mind that the animal kingdom is full of exceptions.
Source: www.slate.fr
