Imvubu Newsletter

© Kigozi, F. 2002 Imvubu 14:2, 2-3.

Faeces, scat, droppings, pellets or wastes are a source of an enormous amount of information about animals in the wild.

These materials, which are primarily waste products, are made up of the by-products of metabolism – i.e. the undigested remains of ingested food, incidental material picked up with food and material taken in while grooming. However, faecal material also serves as a medium of communication, elucidating the social status, behavioural and health condition of animals. Faeces may also serve to identify animal species and determine the size and distribution of wildlife populations. Faeces also provide some insight into the diet of individuals as well as their sex. S

SPECIES IDENTIFICATION FROM FAECES

The form, size and odour of mammalian droppings are often characteristic of the species. However, the faeces of a single animal may vary from area to area, and over time, depending on the diet, size, health and reproductive condition of the individual, time of year and age of the faecal material.

The size of the pellets or scat may depend on the animal’s age, that of young animals being smaller than that of adults. Shape may be influenced by diet. For example, grazing young succulent growth often results in soft fluidy faeces, while old dry grass forms hard dry pellets.

The broad nature of the animal’s diet will influence faecal output, that of a grazer being relatively poor in nutritional quality, which leads to greater quantities of faeces produced relative to that of a carnivore of the same mass. Pellets shrink and lose weight as they dehydrate, so age of the pellets will influence size, mass and sometimes colour. Hyaena faeces are green when fresh and turn white with age. Placement of the faeces and the manner of defecating are often characteristic of the species. Civets defecate in middens, which are often on high vantage points.

ESTIMATION OF POPULATION SIZE FROM FAECAL COUNTS

Faecal counts have often been used in animal censuses. However, this is often done in conjunction with other observations such as the animal’s spoor, nest site or burrow counts. Factors such as the defecation rate of the species and the rate of faecal decay are considered in such indirect censuses.

MAPPING ANIMAL DISTRIBUTION FROM FAECES

The presence of positively identified faeces is good evidence for the occurrence of animals in an area. Faecal materials, fossilized faeces or coprolites are employed by palaeontologists to gain insight into the habitats, diets, behaviour and identity of dinosaurs. Faecal pellets of strictly territorial predatory animals serve as an indirect indicator of the occurrence of their prey. In many cases the only museum evidence of the presence of certain shrews, mice and rats in an area has been derived from owl pellets.

DETERMINING DIET FROM FAECES

The most common use of faecal material in ecological studies has been to assess of the diets of animals. In the case of shy, dangerous or highly endangered species faecal analysis is considered the best method for diet determination. With the use of microscopes, dietary items in the faeces can be identified with precision and preference levels of these items also computed.

DETERMINING SEX FROM FAECES

On the basis of size, smell and deposition site, the use of faeces to determine the sex of an individual animal is fairly widespread among experienced naturalists and hunters.

FAECES AS AN INDICATOR OF PHYSICAL AND HEALTH CONDITION

Normally stress is associated with an increase in the rate of defecation and the fluidity of faecal material. Faeces can also be used to estimate the mass of the individual and therefore to distinguish between adults, sub-adults and juveniles. Many parasites move through the digestive system or release eggs into it, with the result that they are voided with the faeces. Veterinarians often use faecal material to determine the degree of infestation of internal parasites. Reproductive hormones in the faeces of caribou have in the past served as useful indicators of pregnancy.

FAECES AS A MEASURE OF SOCIAL STATUS

The manner in which faeces are deposited and where they are deposited are often linked to social status, particularly among mammals. Within the African hoofed mammals, localised defecation is often attributed to individuals of high ranking status, usually adult males and occasionally females. In conclusion, it is important to note that there are a few sources of error inherent in most faecal based investigative methods, namely aggregated faeces distribution, varying capacities and rates of digestion, and varying rates of faeces deterioration. However, faeces are always readily available and can easily be collected and stored, making their use widespread.