FOREWORD 5 
Animals also often thrive in a climate very different 
from that of their natural habitat. Some animals from 
wai-m countries, though kept outside without any artificial 
heat, get on very well during the severe weather of Phila- 
delphia winters, when the temperature often drops to 
zero Fahrenheit. For the past two years it has been the 
custom to put outdoors all monkeys — of value — that are 
suspected of having tuberculosis. The cheap monkeys are 
killed. The outdoor monkeys are kept in fair sized cages — 
five feet square and six feet high — usually singly, though 
sometimes two are together. The vervet, the grivet, the 
leonine macaque, the yellow baboon, the Hainan gibbon 
and many others, have not only survived the climatic con- 
ditions but have not succumbed to tuberculosis. South 
American monkeys do not stand cold as well as Old World 
monkeys, and cannot be kept out in severe wdnter weather. 
The monkeys that are kept indoors during winter have 
free access to the outside through swinging doors and 
they often go out voluntarily in the coldest weather. The 
same is true of other animals. A note made several years 
ago (February 12, 1914) states : * * Temperature last night 
was 1^ F. At 2 P.M. outside temperature 13° F., in car- 
nivora house 25° F., elephant house 38° F., giraffe house 
39° F., monkey house 42° F. Two Bengal tigers were 
voluntarily outside. Monkeys that have been out all 
winter are : two Barbary apes, Hainan gibbon, lion-tailed 
macaque, yellow baboon, grivet monkey, pig-tailed 
macaque, and eleven rhesus macaques. All the animals 
appeared comfortable." 
The physical condition of the animal and the kind of 
cold — damp or dry — have much to do Avith its ability to 
stand low temperatures. Monkeys have passed through 
very severe winters without damage, and subsequently in 
a less severe winter have had frozen fingers, toes or tail. 
The size of the cage or pen has not as much effect upon 
the well-being of the animal as might be expected. Rep- 
tiles, birds and mammals do as well in cages and pens of 
