Ever Heard of a Left Handed Whale?

It's True: Most Vertebrates Show a Left or Right Preference

by Shreya Dahal, age 13

We all know that most people are either left or right handed. A less known fact is that animals, including those without hands, also often prefer using one side of the body over the other.

Most humpback whales, for example, tend to tilt to the right. Researchers found that when humpbacks dive to the ocean floor in search of prey, they turn onto one side. Then they open their mouths, and glide across the mud. Abrasions found on humpbacks’ cheeks were either on the right cheek or the left, but never both.   

Octopuses tend to use a favorite tentacle to inspect or handle objects. Ninety-two percent of those with a favored tentacle also have a favored eye that focuses directly on the object it is trying to touch.   

Sidedness is found in almost all vertebrate groups. Cats, horses, rodents, reptiles, and many fish species show a preference.
Humans, who are also vertebrates, have sidedness in their hands. While more humans are right-handed than left-handed, a small number of individuals are ambidextrous—they can use both hands equally well.

[Sources: National Wildlife Federation; The Dictionary of Science]