CONDITIONS OF ANIMAL DOMESTICATION 229 



cats, when young, can resist the temptation to kill 

 a cage-bird, and though they can be taught to respect 

 particular individuals, no pigeon or canary is safe 

 from the ' strange cat ' in other words, all other 

 cats but those living on the same premises.* That 

 none of the larger cats except the puma have been 

 even partly domesticated is not surprising. They 

 are the representatives, beyond all others, of the 

 non-communal instinct in animals, living alone or 

 in temporary association limited to the family, and, 

 with the exception of the cheetah, are too dangerous 

 to admit of the encouragement of any initial effort 

 to train them to the service of man. Physical causes 

 only affect domestication in a minor degree. That 

 animals should reproduce their species is an essential 

 condition to their continuance as domesticated species ; 

 and Mr Bartlett considers that the elephant is only 

 ' on the border-line ' because it will not, as a rule, 

 breed in captivity. Its length of life counterbalances 

 this disadvantage. But other species tend to become 

 rather more than less prolific when accustomed to 

 their new conditions. Among water-fowl the widgeon 

 is the only example of a bird which as a rule refuses 

 to pair, and this may in part be due to arrested migra- 

 tion. The turkey of our farm-yards was originally 



* A friend asks, * Are there no mice in Persia ? because Persian cats always seem 

 to kill birds and neglect mice altogether.' 



