Special Problems in Working with Free-Living Animals

Abstract

Although the same basic techniques are used for study and management of disease in wild animals, domestic livestock, and humans, the wildlife specialist encounters difficulties that are unimportant or that can be controlled, literally or statistically, in studies of the other two groups. Most of these difficulties are a result of the “wildness” of the subject animals. The word wild has many meanings, including “growing without the care of man”, “unaffected by civilization”, “of great violence or intensity”, “undisciplined” and “extravagant or fantastic”. No wild animal is unaffected by civilization, since all inhabitants of the globe share effects, such as chlorinated hydrocarbon residues and the greenhouse effect, but most wild animals grow without, and some grow despite, the care of man. Most of the other definitions are applicable to free-ranging species. Disease in wildlife has often been compared to an iceberg, with only a tiny fraction or tip of the total mass being visible at any time. Part of this phenomenon is because very few people are looking for, and even fewer are reporting, disease when it does occur. Disease is notoriously hard to detect, even in humans and domestic animals. However, the covert nature of disease, and particularly its quantitative aspects, is inherently more important in wild animals than in either livestock or humans. The wildlife worker has much greater difficulty finding diseased individuals than does either the physician or the veterinarian, and is seldom able to count wild populations in the wav that cattle in a pen or children in a school can be counted.