Mating Systems - Primatologists use the term “mating systems” to refer the forms courtship, mating, and parenting behavior that are characteristically seen in specific species or populations (Boyd and Silk, 1997). Some examples of mating systems are polygyny and monagamy. For example, both males and females caring for offspring characterize a monogamous mating system. The parents remain as a pair so that they can invest their time and energy raising just a few offspring. This way, the offspring that they do produce will probably survive until adulthood. This example of a mating system is also the one that humans use.

Male-female Relationships – This term is used to describe the way males and females of a certain species or population interact with each other. For example, in the population of baboons in Amboseli National Park in southern Kenya, the older females are the ones who actually make the groups major decisions for them, and the males defer to them in many cirumstances (Altman, 1998). And in bonobo society, male offspring often remain with their mothers long into adulthood (Kano, 1998). The relationships between males and females involve many things including dominance, courtship, and parenting.

Social Systems – This term is classified by primatologists by mating and residence patterns of females and males. The main social systems of primates are Solitary, Monogamy, Polyandry, Polygyny – one male, and Polygyny – multimale/multifemale (Boyd and Silk, 1997). For example, the social system of the dwarf galago is Solitary because males have solitary home ranges that overlap with the solitary home ranges of many females (Isbell, lecture). However, in vervets, they have a Polygyny – multimale/multifemale social system because they live in groups composed of several adult males, adult females, and immature animals (Isbell, lecture).

Ranging Behavior – This term is used to describe the physical living patterns of primates. All primates have home ranges, an area of land where the individual spends most of it’s life, and rarely leaves, but only  some are territorial (Boyd and Silk, 1997). Territoriality is defined as resource defense, and mate defense. Primates that are nonterritorial, like squirrel monkeys, often have home ranges that overlap. For those species that are territorial, however, the boundaries of the territory are the same as those of the home range, and the territories do not overlap. Territoriality occurs when resources are economically defensible (Boyd and Silk, 1997).

The Relationship Between Body Size and Diet – This concept is very important to primatologists because it allows them to predict the diet of an animal just from its body size, and vice versa. A limit of 500 Kg, called Kay’s Threshold, is the limit where an animal must increase its intake of both protein and calories relative to the energy it expends to acquire that food in order to get a balanced diet (Ciochon and Nisbett, 1998). The nature of a species can be reasonable assumed from its body size. For example, you would expect the Aye-aye to be an insectivore because it is fairly small with a high metabolic rate and insects are very high in protein and would be very nutritional for it. Larger animals, however, can be expected to be folivores, because the bigger an animal is, the slower its metabolism is, and things like leaves can be digested for all their nutrients (Ciochon and Nisbett, 1998).

Female Choice – This is the preference of some males over others by female primates. This does not have to be just for mating purposes. It has been shown that bonds between members of opposite sexes can form even in the absence of sexual division of labor, and without sexual exclusivity (Smuts, 1998). Also, it has been shown that males clearly provide females and infants with social benefits, even if they aren’t the fathers of the infants, or the mates of the females. Apparently, female olive baboons associate with many males who are not their mates (Smuts, 1998). This is an example of Female choice.

Infanticide – This term means literally, “the killing of infants”. In primates, this is not necessarily a bad thing. Males of some primate groups with the social structure of Polygyny – one male may actually increase their reproductive success (Boyd and Silk, 1997). This is because when the male takes over a new group of females, any offspring currently in the group are not his, and, while the females are still lactating, they are not sexually receptive. By killing any infants that they have, he can mate more frequently without any detriment to his genetic line. Another aspect of infanticide is that it can occur in any primate species, including humans, if resources are scarce, or the offspring produced does not have a good chance of surviving, and would therefore not be worth the investment of time and energy by the parents (Boyd and Silk, 1998).

Conservation – This term means the protection of a species of its environment by humans. About half of all known primate species are in real concern by primate conservationists (Ciochon and Nisbett, 1998). The three major threats to wild populations are habitat destruction, hunting, and live capture for export. As habitat is destroyed, the animals have less and less areas in which to find food and shelter. Therefore, if you can conserve the habitat, you can also conserve the species. This process, however, worked in reverse for the white ukaris in Brazil. After a study of the animal, it’s home range was set up as an Ecological Station, there by protecting the endangered rain forest from outside threats (Ayres, 1998).