Aquarium Number 
PREPARED BY THE ASSISTANT DIRECTOR OF THE AQUARIUM 
ZOOLOGICAL 
SOCIETY BULLETIN 
Number 42 
Published by the New York Zoological Society 
November, 1910 
ADAPTIVE 
COLOR CHANGES 
AMONG FISHES.* 
By Dr. F. B. Sumner, 
Director or THE U.S. FisHertes Laporarory, Woops Horr, Mass. 
Illustrated from photographs by Dr. Sumner. 
N the Thirteenth Annual Report of the New 
York Zoological Society, Dr. Charles H. 
Townsend has described and figured some of 
the color changes undergone by fishes of a num- 
ber of species in the New York Aquarium. 
Now, such changes as form the subject matter of 
that article, although of great interest in them- 
selves, probably have no adaptive significance in 
the majority of cases. They are nervous re- 
*The general results of these investigations were 
presented before the American Fisheries Society, New 
York, September 28, 1910. A fuller and more tech- 
nical account will be published shortly. The studies 
were made, for the most part, at the Naples Zoolog- 
ical Station. 
flexes, called forth by some disturbance of the 
fish, and may be of no more utility to the animal 
than are blushing and various other manifesta- 
tions of emotional excitement in ourselves. 
The present writer has devoted considerable 
study to the color changes of certain species of 
flounders, with especial reference to the influence 
of the bottom on which they lie. The most 
striking results were obtained from a member of 
the turbot group, Rhomboidichthys podas, oc- 
curring in the Bay of Naples. It was found 
that this fish not only adapted itself to the gen- 
eral color tone of the background, but to the 
texture and pattern as well. Thus most speci- 
mens not only assumed a very dark shade upon 
Fic. 1 
z Fic. 2. 
PHOTOGRAPHS OF THE SAME FISH ON DIFFERENT BOTTOMS. 
