Science: Fish Society

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To Zoologist Gladwyn Kingsley Noble of Manhattan's American Museum of Natural History, fish are not gawping, cold-eyed nonentities, but personalities as ambitious and sociable as human beings.

"Fish left together in groups get to know one another personally," wrote Dr. Noble in the Collecting Net* last week, "even where there are no sexual or individual external differences which the human eye can distinguish. [They form] social hierarchies. One fish can strike a second fish without being struck in return, and the second has the same right of 'passing the blow' to a third individual. These . . . 'pecking orders' owe their existence not to strength but to psychic factors, such as the period of residence in an area. . . . Many fish devote most of their energies to trying to change their social status."

Social behavior in fish, Dr. Noble believes, depends on their forebrains. When the forebrains of ordinary, sociable minnows are removed, the fish leave school, become hermits. Strangely enough, "such fish may seem in other respects more effective organisms than fish with intact brains. [They] . . . respond to food more quickly ... exhibit much greater vigor in flight reactions, exhibit less caution. . . . The operation seems to improve their personalities, but their social relations are completely lost." Fishman Noble also noted that the sex glands of partially de-brained fish degenerate and they lose interest in breeding. When pituitary hormones are injected the fish swim out in search of mates again, although they no longer hatch eggs in the same seasons as the rest of their friends.