The Biology of the Crocodilia 17 
ful head, and during the breeding season especially 
is more brilliantly colored.” 
It is a very common belief, even among those 
who should be most familiar with their habits, 
that the growth of the alligator is remarkably slow, 
so that a large specimen may be described by the 
exhibitor as more than a century old. The same 
dealer in alligators quoted above says upon this 
subject: ‘“You can figure about two inches a year 
to their growth.’”’ He also says: ‘‘We judge that 
an alligator about twenty-five to thirty years old 
will breed.’”’ Even scientific writers of reputation 
have not been free from this error in their writings. 
That the alligator may live to an extreme age, as 
seems to be true of some of the tortoises, is quite pos- 
sible, and it is probable that after reaching a length 
of twelve or fifteen feet the growth is very slow. 
In captivity, when kept in warm water and 
other favorable conditions, the alligator will grow, 
according to measurements taken at the New York 
Zoological Park, at the rate of about one foot a 
year, for about the first ten years. Under unfavor- 
able conditions the growth may be exceedingly 
slow. Under favorable conditions in nature the 
rate of growth may exceed that given above. 
Instead of requiring twenty-five to thirty years 
to reach sexual maturity, as quoted above, it is 
likely that the female may lay eggs at five to ten 
years, though such a fact is difficult to determine 
of animals in their native haunts. 
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