332 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1941 



animals must be made adequate as to safety, must provide ample 

 space for the animals to move about and obtain exercise, and should 

 be so constructed as to be easily cleaned. Large enclosures that are 

 fenced for retaining such animals as horses, zebras, deer, antelope, 

 kangaroos, etc., may be of almost any convenient size, depending on 

 the area available. They may be large pastures in which people 

 may walk or drive. If the general public is to view the animals from 

 outside the enclosure, it is preferable that the enclosures have a depth 

 from front to back of from 150 to 200 feet; a greater depth is likely 

 to permit the animals to get so far away that the public does not 

 obtain a good view of them. The front, w^here the public is to pass, 

 may be of any convenient length, but should not be less than 50 

 feet for the larger animals. The restraining barriers for enclosures 

 of this type can be wire fences, palisades, rock walls, or moats, or 

 combinations of any or all of these. The moat treatment requires 

 greater ground area, but is particularly effective in that there is no 

 obstruction of the view. If the moat is properly constructed, the 

 animals can be entirely secure. 



The conventional cage varies from small bird cages made of wire 

 or partially of glass, to large cages adequate for gorillas and other 

 powerful or dangerous animals. The size and, to some extent, the 

 type of material to be used will largely be determined by the kind 

 of animal to be enclosed. In general, no cage should be smaller 

 than five times the length of the animal, although probably the 

 majority of animals are kept in smaller enclosures. Since maximum 

 visibility of the animal is particularly desirable, the cage should be 

 of strong material of small dimensions so that it will cause the 

 minimum obstruction to the visitor's view, at the same time furnish- 

 ing adequate security. Glass can be used for many cages. 



In constructing cages side by side, there should either be a solid 

 partition between them so that the animals cannot get their toes, 

 fingers, arms, or legs through into the adjoining cage where they might 

 be bitten or otherwise injured, or, if mesh partitions are used, these 

 should be double and far enough apart so that the animals cannot 

 reach into the adjoining cage. 



Aquaria and tanks can vary in almost infinite degree, from the 

 cans or pans in which small boys frequently and sometimes success- 

 fully keep fishes, toads, frogs, and turtles, up to elaborate aquariums 

 and large tanks. 



Restraining the animal by means of a collar about the neck or, in 

 cases of some monkeys, a belt immediately in front of the hips, or a 

 strap on the legs of birds is frequently practiced. Before leaving 

 an animal entirely unwatched in the early stages of making it secure 

 in this manner, it is well to make certain the animal does not become 

 entangled in the chain or leash attached to the collar or belt. Some 



