176 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Most small crocodiles produce some noise or other. 

 The different species in a tank can be distinguished by 

 their especial calls. The Mississippi alligator has a sharp, 

 short and high-pitched grunt, the broad-fronted crocodile 

 is similar, but less musical and shorter even. The rough- 

 eyed Caiman rarely produces any sound. When it does, 

 it resembles the grating together of dry sticks. The 

 American crocodile has a prolonged lower, and more 

 grumbling note, frequently repeated. The Egyptian's is 

 a deep short sound, like a young puppy's early attempt at 

 a growl. These sounds or calls seem to be indicative of 

 either hunger or satisfaction, and the animals will respond 

 to the human voice when they get used to their keeper. 

 Anger is evinced by a long-drawn hiss, produced by a 

 deep inspiratory effort, the other sounds are expiratory. 

 Very little seems to be known definitely about their rate 

 of growth. One alligator in my possession grew half an 

 inch in length in a calendar month, and in eight weeks 

 it grew one and three-quarter inches, then measuring 

 sixteen and three-quarter inches. An Egyptian crocodile 

 in six or seven months growing about two inches. When 

 first measured this specimen was twenty-five inches long. 

 Their growth in captivity seems to be very erratic. An 

 American crocodile in three months increased one inch in 

 length, then measuring thirteen and a half inches ; a 

 small Caiman in three months growing only one inch. 



One meal each morning should be enough for most 

 specimens, except in two cases ; the first being in very 

 small specimens, when a smaller amount may be given in 

 the evening. The second case would be when there was 

 much disparity in size ; then it might be better to avoid 

 leaving a large specimen hungry with small ones perhaps 

 half, or even less, his size. 



They can easily be trained to take their food oft' a 



