A team of researchers coordinated by neuroscientist Daniel Cattaert, from the University of Bordeaux, in France, has discovered that some crustaceans, such as crayfish, show some anxiety when under stress.
In a study published in Science , these experts emphasize that under these conditions, these animals show high levels of serotonin , a neurotransmitter that can also be found in high concentrations in stressed humans.
The scientists also found that if they injected the crustaceans with chlordiazepoxide , a compound that is used as an anxiolytic in many treatments, the crabs calmed down . To check how they responded, the researchers applied small electric shocks to some of them and placed them in a cross-shaped aquarium, specially designed so that some areas were well lit and others remained in the dark.
The stressed specimens, which had received the current, avoided the areas with light, probably as a defensive tactic , while the other specimens roamed through them without problem. However, if these were administered serotonin, they exhibited the same cautious behavior as the former.
The researchers clarify that their findings do not clarify whether crustaceans experience stress or anxiety in the same way that we do , but they suggest that the mechanism behind these phenomena is similar and that, from an evolutionary point of view, it could have the same source.
“Crabs have been on the planet for hundreds of millions of years . They are primitive. And yet, until now, the idea that they could express some kind of anxiety didn’t seem possible. However, with our tests we are more and more convinced that this is the case, ”says Cattaert.
