348 Biology in America 



them, and in some cases will pick up bits of leaves, etc., which 

 never in any likelihood form part of their normal food under 

 natural conditions. Stomach examinations however show 

 that supposedly disagreeable insects form a considerable part 

 of birds' food. Thus hairy caterpillars, stinging bees and 

 wasps, ants and species of foul-tasting or smelling bugs and 

 beetles are eaten by a great variety of birds. 



Greater doubt is cast upon the theory of warning color by 

 the work of Reighard at the Dry Tortugas. These are isolated 

 groups of coral islands lying off the Florida coast, and sur- 

 rounded by coral reefs. Inhabiting these latter are many 

 species of brilliantly colored fishes, which supposedly come 

 within the category of warningly colored forms. Living in 

 the same reefs is a predaceous fish, the gray snapper. Reig- 

 hard has shown that the brilliantly colored fishes of the reefs 

 are readily eaten by the snapper, once they are outside the 

 protection of the reefs. That the snappers can distinguish 

 different colors however and can learn to associate them with 

 unpleasant tastes was proved by attaching the stinging ten- 

 tacles of a jellyfish (Cassiopea) to a small fish upon which 

 the snappers commonly feed, and coloring the prey red. 

 After several unpleasant experiences the snappers learned 

 to leave the red fish severely alone, whether with or without 

 the tentacles attached, while they took fish which were colored 

 white even though the stinging tentacles were attached to 

 them. 



Longley also has made extensive studies of these fishes, as 

 a result of which he finds that the apparently conspicuous 

 and contrasting colors of so many coral reef fishes are really 

 protective, harmonizing their possessors with their surround- 

 ings and have no relation to warning color whatever. Long- 

 ley strongly inclines to the hypothesis of Thayer that the 

 greater the contrasts in an animal's color, the more readily 

 will it harmonize with its background, a principle most 

 strikingly illustrated in the bizarre effects of our camouflaged 

 ships in the recent war. 



