Comparative Primate

Lemurs

 Lemurs live in trees which is why they are called arboreal. There are some large species of Lemurs though that also spend time on the ground. They are only found on the Comoro Islands and Madagascar Islands. This is off of the Southeast coast of Africa. But on these islands, lemurs live in a variety of habitats. Some live in moist, tropical rainforests, while others live in dry desert areas.

For most species of Lemurs the mating season is very short. This is usually less than three weeks per year. The female will likely only be in estrus for a few days annually. Healthy females seek out multiple mates in the few hours of one night they are receptive to mating every year. These multiple mates must have some kind of benefit to the females; however is not know how much. Males get benefits from mating with multiple females, because they can impregnate multiple partners .The social structure of the Lemur is very interesting. They live in small groups usually less than 15 individuals. These family groups have females that have power over the males. It can be very difficult to tell the difference between the males and the females. Social organization patterns include solitary but social, pair bonds, and multi-male group. Nocturnal lemurs are mostly solitary but social, foraging alone at night but often nesting in groups during the day. The degree of socialization varies by species, gender, location, and season.  The environment Lemurs live in has influenced the way they mate. Because Lemurs only mate a few months out of the year males can take advantage of this and mate with different female Lemurs.

Spider Monkey

Most spider monkeys can be found in the regions of South America, Central America, and Mexico. They live in tropical rain forests. Within these tropical rain forests, spider monkeys like to stay near the top of the canopy of trees. This helps keep them away from spider monkey predators roaming the forest's floor.

They are social animals and live in bands of up to 25 individuals but will split up to forage during the day. Spider monkeys form loose groups of 15 to 25 animals. During the day, groups break up into subgroups of two to eight animals. This social structure is found in only two other types of primates, chimpanzees and Homo sapiens. The size of subgroups and the degree to which they avoid each other during the day depends on food competition and the risk of predation. The average subgroup size is less than four animals. Males tend to stick together for their whole lives. Therefore, males in a group are more likely to be related and have closer bonds than females. The strongest social bonds are formed between females and their young offspring. The female chooses a male from her group for mating. Both males and females use genital sniffing to check their mates for readiness for copulation. The gestation period ranges from 226 to 232 days. Each female bears only one offspring on average, every three to four years. Dividing into subgroups allows the spider monkeys to avoid predator and find food a trait that have been influenced by their environment.

Baboon

Baboons are found in surprisingly varied habitats and are extremely adaptable. The major requirements for any habitat seem to be water sources and safe sleeping places in either tall trees or on cliff faces.  The grasslands, especially those near open woodland, do make up a large part of its habitat, but the baboon also inhabits rainforests and deserts. Uganda and the Democratic Republic of the Congo, both are a home for baboons. When water is readily available, baboons drink every day or two, but they can survive for long periods by licking the night dew from their fur.

The olive baboon lives in groups of 15–150, made up of a few males, many females, and their young. Each baboon has a social ranking somewhere in the group. Female dominance is hereditary, with daughters having nearly the same rank as their mothers, with adult females forming the core of the social system. Female relatives form their own subgroups in the troop. A female will often form a long-lasting, social relationship with a male in her troop, known as a "friendship". These non-sexual friendships benefit both the male and female. Males benefit from these relationships because they are usually formed soon after he immigrates into a new group. Forming a friendship with a female member helps the male integrate into the group more easily. He could also potentially end up mating with his female friend in the future. Females gain protection from threats to themselves and their infants. Also, a male will occasionally "baby-sit" for his female friend, so she can feed and forage freely without having to carry or watch the infant. These friendships are sometimes formed between sexually receptive females and newly immigrated males. These relationships are sometimes enduring and the pair will groom and remain close to each other. The beginning of their ovulation is a signal to the males that she is ready to mate. During ovulation, the skin of the female's genital area swells and turns a bright red/pink. Females with larger swellings attract more males and are more likely to cause aggressive fights between them. I think Baboons stay in large groups to try to stay safe from predators and having a greater chance of survival.

Gibbon

Gibbons live in old growth tropical rain forests in Southeast Asia. Gibbons are highly arboreal and move by  swinging from handhold to handhold under branches and vines, using their long fingers as hooks.

Gibbons are social animals and form pair bonds. Strongly territorial, they defend their boundaries with vigorous visual and vocal displays commonly sung as duets by mated pairs. Gibbons live in small, monogamous families composed of a mated pair and up to four offspring. Gibbons are one of the few apes where the adult female is the dominant animal in the group. The hierarchy places her female offspring next followed by the male offspring and finally by the adult male. In most species, males, and in some also females sing solos to attract mates, as well as advertise their territories. If a male and female like each others song, they will find the other. Gibbon and do a short mating dance followed by a vigorous mating ritual that lasts three days, and they will mate about five hundred times in this time period. Gibbons must rather stay in small groups to avoid food and mating competition.

Chimpanzee

There are only 21 countries in which chimpanzees live in the wild, all found in Africa. Common chimpanzees are able to live in a wide variety of habitats. These include rainforests, woodland areas, swamp forests and a number of other areas. Their main requirement is that there be plenty of trees.

Chimpanzees live in large multiple-male and multiple-female social groups called communities. Within a community, a definite social hierarchy is dictated by the position of an individual and the influence the individual has on others. Chimpanzees live in a leaner hierarchy in which more than one individual may be dominant enough to dominate other members of lower rank. Typically a dominant male is referred to as the alpha male. The alpha male is the highest-ranking male which controls the group and maintains order during any disputes. In chimpanzee society, the 'dominant male' does not always have to be the largest or strongest male, but rather the most manipulative and political male which can influence the goings on within a group. Female chimpanzees also have a hierarchy which is influenced by the position of a female individual within a group. In some chimpanzee communities, the young females may inherit high status from a high-ranking mother. When mating male chimpanzees prefer older female chimpanzees. Estrus in females starts at 10 years, at which time their anus and genitals swell. Female chimpanzees are considered promiscuous; however, I believe this is because they are only able to have one off-spring at a time they need to find the best mating partner.

4. I believe that the environment had a huge effect on the physical and behavioral traits. Many of these Primates live in large numbers because it increases their chance of survival. This is why I believe that the environment and there surroundings influenced these type of behaviors. Also, their ability to climb on trees and swing from branch to branch is something that has evolved through time because of the environment where they inhabit.