CARE OF CAPTIVE ANEMALS — WALKER 309 



sun is often fatal to snakes and lizards that are inhabitants of 

 desert regions and are supposed to enjoy the sun. They regularly 

 seek the shade during the hot portion of the day in hot weather; or 

 they burrow in the sand or under stones to get out of the intense 

 heat. Small den houses become unbearably hot when in the sun. 

 Shade should be provided for such enclosures in hot weather. 



Animals that particularly require sunshine frequently develop ill 

 health and become unsightly because they do not get enough sunlight 

 or ultraviolet rays. This can frequently be remedied by installing 

 ultraviolet lamps at the cages so that the animals can go into the 

 rays to such extent as they wish. Such rays can be harmful if the 

 animal is subjected to them too much. 



Sunlight is not essential or even desirable for certain animals, 

 for, being nocturnal, many of them never see the sun, not coming out 

 into the open until the sun is set, and going to bed before the sun 

 rises. Others live subterranean lives entirely away from the sun- 

 light. Presumably such creatures obtain, through their food, the 

 materials that are manufactured by other animals in sunlight. 



Developments in air conditioning, refrigeration, and special types 

 of lighting now make it fairly easy to provide physical surroundings 

 that closely approximate those of the climate in which animals would 

 normally live. The big problem is to furnish suitable substitute 

 foods. In the wild, some of the animals are what we term "speci- 

 alized feeders," that is, they eat but very few kinds of food. At first 

 thought such foods may not appear to furnish well-balanced diets. 

 However, careful consideration will disclose the fact that their 

 limited diet does provide a well-balanced ration for them. Feeding 

 these animals is sometimes the most difficult of all problems, and at 

 other times it is very simple, depending on whether or not we are 

 able to furnish palatable substitute foods that contain the necessary 

 constituents. Other animals take a wide variety of foods in the wild, 

 a nibble of this and a nibble of that, obviously selecting things that 

 are palatable to them and that contain the constituents necessary for 

 their well-being. Careful study of the feeding habits of such animals 

 in the wild discloses a surprising variety of food consumed. Some- 

 times they may eat a limited variety for a short period, but with 

 the changes of the season, the diets may be radically changed. In 

 some instances, such changes appear to be necessary for physical de- 

 velopment and growth. For example, many young birds, such as 

 finches and others, are fed insects by their parents, whereas the adults 

 eat mainly seeds for most of the year, and insects for only a short 

 season. In others, the changes appear to indicate a wide food toler- 

 ance that permits the animal to survive under seasonal conditions that 

 vary greatly from one time of the year to another. 



