This just in from the Grand Academy of Lagado, administering electric shocks to crayfish can make them 'fear' the prospect of future electric shocks.
An experiment showed that the humble freshwater crayfish can be induced into a state of deep anxiety - one that can only be alleviated by the same type of tranquilisers used to treat humans.
The invertebrates, somewhat understandably, became nervous and flicked their tails as an escape response as a result of being subjected to the shocks.
Fear: an aversion to an imminent threat is almost universal in the animal kingdom. Rodents have been shown to fear the smell of a predator, and birds in a nest will lie low when a hawk flies overhead.
Love: bonding and attachment are also universal. Some animals, such as swans, will form long-term mating bonds.
Sadness: any dog owner will attest to the ability of a pet to show signs of sadness, and elephants and chimpanzees have been shown to mourn their dead.
Happiness: social mammals such as wolves are particularly good at displays of “happiness”.
Scientists from the University of Bordeaux in France said they believed it was the first time a state of anxiety normally associated with higher forms of life had been identified in a species that is literally spineless.
Anxiety is different from fear, which is something that even the simplest animals show. Anxiety is a kind of fear of the fear, and animals who experience it will display adaptive behaviour to minimise the threat.
It doesn’t mean that the emotions are the same, although we have found that the mechanism that has been developed in vertebrates is also present in crayfish. But I wouldn’t say that this changes totally our view of crayfish.
Daniel Cattaert, neuroscientist