Great Uncle Fred, do fish sleep? (Pauline, Summer 2009)

Well, Pauline, it would be interesting to find out what led you to ask this interesting question. It is interesting but I think that your biology teacher might be better at answering it than me. Perhaps your biology teacher is an exceptionally busy biology teacher. It is, apparently, a controversial subject which has had a whole book written about it. I think it is controversial because fish do not have eyelids and they do not have a developed neocortex in the brain, like we do. Because they have no eyelids you cannot tell if they are sleeping, but they certainly do rest and become almost unconscious, and because our sleep is defined by the change in patterns in the neocortex, it cannot really be said that fish sleep as we do. But their metabolic rate slows down and all that sort of thing. Some fish hibernate, some fish estivate - carp spend the winter partly buried in lake mud. I think it would be fair to say that the simple answer to your interesting question is "Yes".

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