The positions of most fishes鈥� eyes mean they cannot see their own body. So, how do they recognise others of their own species? (cont.)
Shelby Temple
University of Bristol, UK
Humans, and most animals for that matter, have eyes fixed in their heads in a manner that doesn鈥檛 allow them to see their whole self. Snails and animals whose eyes are on stalks might be the exception. Therefore, the same question applies to us.
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Some of it will be innate and some of it will be learned, just like how a baby human sees the face of its parents and learns to recognise them. We also know that, for some species, this imprinting can be tricked: this is how Konrad Lorenz, the 鈥渇ather of ethology鈥�, became the imprinted parent of newly hatched ducks and geese.
Fish are probably no different and can learn to remember people and faces for various benefits. My own archerfish learned to differentiate me from my wife and other guests, because I was the only one who fed them. So, I think the ability to see yourself isn鈥檛 really a prerequisite to recognising your own species.
Given the importance of staying in schools for some species of fish, I suspect they use a variety of inputs, including visual and olfactory, plus learned experiences of safety versus danger. Then there鈥檚 innate recognition, which must play a role in some species of fish that are so sparsely distributed that, when a male meets a mate, they attach to them and never let go, for example deep-sea anglerfishes.
I doubt a male deep-sea anglerfish in this situation has ever seen itself or even another individual of its species before, but it still seems to know to attach itself to a female.
In this case, it is almost certainly down to an olfactory cue, but there will be many other interesting and bizarre examples in the world of fish.
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