FOREWORD 
This is true even of the lowly forms. The keeper of the 
reptile house reported that a giant tortoise became 
despondent and refused to eat when his companion, a 
leopard tortoise, was taken from him, and that he braced 
up as soon as the leopard tortoise was returned. It is not 
necessary that the companion be of the same species, or 
even of the same family. A lion or a tiger may be satis- 
fied with a little dog for a companion, and there was an 
African rhinoceros at the Philadelphia Garden that was 
very discontented and unliappy when alone and became 
perfectly satisfied when she was given a domestic goat as 
a cage-mate; and the huge rhinoceros stood for a good 
deal of butting and bullying from the goat without 
retaliating. A sympathetic keeper may do much to relieve 
the loneliness of the animals in his care. 
Nostalgia, or homesickness, has been felt by all men. 
Some have died of it. The tradition among writers is 
that it affects young people and those who have been 
living nearest to a state of nature. In this country the 
American Indian and the negro are affected more than 
the whites. Much was written of it after the Franco- 
Prussian War and the American Civil War. It is a real 
condition, capable in extreme cases of causing death and 
of so weakening the sufferer as to make him more suscep- 
tible to the invasion of other diseases. At the present day 
we hear less of it among civilized people than formerly, 
perhaps because the conception of home has been broad- 
ened by modem methods of intercommunication. The 
wild animal's conception of home is narrow; he comes 
directly from it into an environment where he may see 
many other animals, but not one of his own kind. Pre- 
disposing causes of nostalgia are stronger with him than 
with the human. That home means a great deal to 
animals is shown by the migration of birds — the return of 
the carrier pigeon, and of the lost dog, and of the swallow, 
which returns every year to the same nesting place. 
