FISH LORE

(from Fish Behavior in the Aquarium and in the Wild, by Stephan Reebs, Cornell University Press 2001) p. 197

"Late one day, Lorenz (fish researcher and one of the founders of ethology) came to feed a pair of parental jewel chichlids he was keeping in his laboratory.  That pair had just about finished retreiving their young for the night--like many cichlids, jewels at dusk gather their free-swimming young a few at a time into their mouth and spit them into a pit so that they can watch over them at night.

The female was holding station over the pit full of fry, while the male was dashing back and forth, looking for stragglers.  Lorenz dropped a piece of earthworm into the water.  The female did not flinch from her guarding post, but the male rushed to the worm, seized it, and started chewing.  Then he saw a stray fry swimming by itself away from the pit.  Bent on retrieving it, he took it in his already full mouth--and then paused.  What to do?  To eat or not to eat? To retrieve or not to retrieve? Part of the mouth content had to go to the nest, the other to the stomach.

After a few moments, the father found a solution: he spat out both the worm piece and the young.  Both sank to the bottom--sinking is a reflex in young cichlid fry being retrieved, and as for the meat, well, that was only gravity.  Then the father ate the worm, taking his time and watching the nearby fry.  When he was done, he took the fry in his mouth once again and brought it back to its waiting mother. 

Nearby students watching the scene spontaneouslybroke into applause.  The decision by the fish almost made him look wise.