Bolder Fish Have Svelter Shapes

Scientists find a link between personality and body type

A zebrafish
A zebrafishPhoto by Brian Langerhans

Scientists at North Carolina State University have taken a good hard look at zebrafish and determined that those that are bred to be bolder turned out to have better swimming abilities and different body types than those that weren't.

If your first question is “what is bred to be bold?” I’m with you. Boldness in zebrafish is determined based on how quickly they start moving after being placed in a new environment.

So, in the study, researchers studied bold fish (those that stayed still for only 50 seconds or less), and shy fish (those that stayed still for more than 3 minutes). They began to see that the bolder-bred fish actually had longer bodies, larger tails, and moved more quickly. Shy fish were less svelte and moved slower.

At face value, it does sort of make sense that these traits would be related. But, it is surprisingly that a personality trait could show up in morphology. These findings could end up affecting animal breeding and even pest management in the future, according to North Carolina State's press release.