full story, comments, photos:
The Emotional Lives of Crayfish: Stress and Anxiety
June, 13, 2014 in Animal
A new study has shown that crayfish, those "delicious" beings some people
choose to eat, actually feel
stress and respond
the same as humans when
given a drug used to treat anxiety. The results of this very interesting
study are reported in the prestigious journal, Science, in an essay titled "Anxiety-like
behavior in crayfish is controlled by serotonin". However, it is only
available to subscribers.
The research team
lead by Pascal Fossat in the Department of Life Science and Health, Université
de Bordeaux (France), concluded that this research "may alter our conceptions of
the emotional status of invertebrates." When Professor Fossat and his colleagues
mildly shocked crayfish, they placed them in an aquarium maze containing
pathways that were well lit and dark. The shocked and stressed crayfish strongly
preferred the dark paths and rarely entered the lighted ones, whereas the
non-stressed crayfish also preferred the dark pathways but also entered the
What is incredibly interesting is that light avoidance by the stressed
crayfish is associated with heightened levels of the
neurotransmitter serotonin that also is associated with human moods. In
addition, injecting crayfish with serotonin made them anxious and treating them
with the drug chlordiazepoxide that's used to treat anxiety in humans reduced
the anxiety in the stressed individuals. They then entered lighted pathways.
The ever-expanding sentience club
When I read about this fascinating research I was reminded of
research that demonstrated that crabs feel pain and work that was done on
honeybees that showed that they too
display human-like responses to stress and depression. The bees showed
altered levels of neurochemicals (dopamine,
serotonin, and octopamine) that are associated with human depression.
These fascinating studies show that we need to be very careful making claims
that invertebrates do not have emotional lives or feelings. In fact, there are
marked similarities with vertebrates including humans.
Many other invertebrates who supposedly don't feel pain are served up as food in
countless billions and it's time to reconsider how these animals are treated in
the food industry and to eliminate pain from the menu. Researchers agree.
Please stay tuned in as more "surprises" are revealed about sentience in other
animal beings and how they really do not live pain-free lives. Membership in the
sentience club is ever-expanding.