320 



ORDERS OP REPTILES— CROCODILES AND ALLIGATORS 



duce by laying from thirty to sixty oblong, per- 

 fectly white eggs, in layers, in a low mound of 

 muck, or vegetable mould, or sand. The female 

 lies in wait to defend her eggs while they hatch 

 through the heat of the sun, or by regular fer- 

 mentation. From the nest of the salt-water 

 crocodile I have taken fifty-five eggs, from the 

 gavial, forty-one and forty-four, from the Florida 

 crocodile, twenty-six, and from the alligator, 

 thirty-eight. The nest of the alligator is about 

 two feet high and four feet in diameter. 



At birth, young alligators are about eight 

 inches long. As soon as they are out of the 

 shell, they are wide-eyed and alert, and ready to 

 take to the water. At this period, the muzzle is 

 short, abnormally broad, and the arch of the 

 forehead very high. 



Growth and Size. — In the Reptile House of 

 the New York Zoological Park, we have recorded 

 the following facts regarding the rate of growth 

 of our alligators: 



Inches. Weight. 

 Length when hatched, 8 If oz. 



one year old, 18 9J " 



22 months old, 23 3 lbs. 



29 " " 45 14 " 



An alligator when received measured 6 ft. 11 in. 

 During the first year it grew 1 ft. 



3 in. and measured 8 " 2 " 



During the second year it grew 1 ft. 



H in., and measured 9 " 3 " 



During the third year it grew 1 ft. 



7 in. and measured 10 " 11 " 



Length of "Old Mose," July, 1899, 12 feet. 

 Length of "Old Mose," July, 1903, 12 feet 5 in. 



Judging by the rate of growth of specimens of 

 all sizes under constant observation in the Zoo- 

 logical Park, where they probably are growing 

 as rapidly as they could in a wild state, I have 

 reached the conclusion that, under ordinary 

 circumstances, a wild crocodile or alligator is 

 about ten years in attaining a length of twelve 

 feet. The average rate of growth up to twelve 

 feet appears to be about 1.4 inches per month. 

 After twelve feet has been attained the rate is 

 much slower, being (in the case of our largest 

 specimen) about two inches per year. 



The secret in securing rapid growth in captive 

 crocodilians lies in giving them a pool four feet 



deep, of water warmed to a temperature of be- 

 tween 80 and 90 degrees F. If kept in cold water, 

 and but little of it, they are uncomfortable, they 

 feed sparingly, and grow either very slowly, or 

 not at all. 



AMERICAN SPECIES OF CROCODIL- 

 IANS. 



The Florida Crocodile 1 is the type which 

 represents the midway average between the two 

 extremes of the crocodilian series, — narrow- 

 beaked gavial and broad-snouted alligator. It is 

 a subspecies of the so-called "American" croco- 

 dile (Crocodilus acutus), of Central and South 

 America, and is not found elsewhere than in 

 southern Florida. It is the only crocodile which 

 inhabits a country that is visited by killing 

 frosts. 



The presence of a true crocodile in Florida was 

 not discovered until 1875, when a pair of speci- 

 mens of large size were collected in Arch Creek, 

 at the head of Biscayne Bay, by Mr. C. E. Jack- 

 son and the writer. The male measured 14 feet 

 2 inches (with 4 inches of his tail missing), and 

 the female 10 feet 8 inches. Since that date, at 

 least seventy specimens have been taken be- 

 tween Lake Worth and Cape Sable. Lake 

 Worth is the northern limit of the species, but 

 it is most abundant in the watery labyrinth of 

 low land and shallow water where the mainland 

 of Florida reluctantly sinks into the Gulf. 



The alleged "big 'gator" of Arch Creek was 

 very wary, and permitted no boat to approach 

 within rifle-shot. Even a boat completely masked 

 by green branches, and innocently floating with 

 the current, was enough to send the old fellow 

 quickly sliding from his basking-place on the bank 

 into deep water. At last, however, we shot him 

 from an ambush in the mangroves opposite his 

 mid-day lair, and secured him. His mounted 

 skin is now to be seen in the United States Na- 

 tional Museum. 



The adult male Florida Crocodile is very rough, 

 externally, and usually its natural colors have 

 been so far obliterated by age and exposure that 

 on its upper surfaces its color is a dull, weather- 

 beaten gray. The females, and males under 

 eleven feet, are of a clean, grayish-olive color, — 

 or dull yellowish-green, — very different indeed 

 1 Cro-co-di'lus a-cu'tus flor-i-dan'us. 



