Comparative Primate Blog Post

Lemurs (Prosimians/Strepsirhini):

a.)   Lemurs are forest creatures, many species live in Madagascar’s tropical rainforests, but some live in dry deciduous forests with dry brush and scrub, but can also be found in closed canopy forest. Lemurs have the most restricted range of all primates, being found exclusively on the island of Madagascar and the nearby Comoro Islands, where they do not have to contend with competition from the more advanced non-human primates. Ring-tailed lemurs spend a lot of time on the ground, almost as much time on the ground as in the trees; which is unusual among lemur species. They forage for fruit, which makes up the greater part of their diet, but also eat leaves, flowers, tree bark, and sap. The pygmy mouse lemur is the smallest primate in the world. Its head and body are less than two and a half inches long, though its tail is a bit more than twice that length. Unlike other lemur species it is found in open areas and will walk along the ground as well as moving between the trees

b.)  Ring-tailed lemurs live in groups known as troops. These groups may include 6 to 30 animals, but average about 17. Both sexes live in the troops, but a dominant female presides over the group. Lemurs are unusually sociable for prosimians, this is especially true of the ring-tailed lemurs. Unlike most other primate species, lemur females generally dominate males in their social interactions. They communicate through powerful scent glands and use their unique odor as an interaction tool. During mating season, male lemurs battle for dominance by trying to out-stink each other. They cover their long tails with their smelly secretions and wave them in the air to determine which animal is most powerful. After successfully mating, some lemur species, such as the dwarf and mouse lemurs, have litters of two or more young. Others, such as the sifakas and ring-tailed lemurs, give birth to only one baby at a time.

c.)   During an evolution that lasted millions of years, different species developed. Lemurs’ behaviors and adaptations evolved differently from the primates in other parts of the world. Lemurs have strong hands and fingers to help them to climb trees easily and their muscular legs are adapted for jumping. They have also formed troops for security, there’s safety in numbers. Hawks and other predators are less likely to attack a group than a lone lemur. 

Spider Monkey (New World Monkey/Platyrrhini) :

a.)   New World monkeys, like the spider monkey, are limited to  the tropical forest environments of southern Mexico, Central, and South America. The tropical rainforest provides a comfortable and safe environment for the monkeys to inhabit. Spider monkeys find food in the treetops and feast on nuts, fruits, leaves, bird eggs, and spiders. Spider monkeys spend almost all of their time in the canopy and rarely descend to the forest floor.

b.)  These New World primates are social and gather in groups of up to two- or three-dozen animals. At night, these groups split up into smaller sleeping parties of a half dozen or fewer. Foraging also occurs in smaller groups, and is usually takes place early in the day. Spider monkeys can be noisy animals (I’ve experienced this myself) and often communicate with many calls, screeches, barks, and other sounds. Mating between black spider monkeys first involves the female approaching a potential male and presenting her genitals. If he shows interest, the mating pair separate themselves from the group either briefly or up to several days. If a female is ranging in a subgroup without males, she will react to the calls of males from neighboring groups by leading her group in the direction of the calls and will either choose to mate with one of the males of this new subgroup or will continue on, looking for other potential mates. Typically, females give birth to only a single baby every two to five years.

c.)    One characteristic that defines the New World Monkeys is the presence of a prehensile tail. A prehensile tail is characterized by having a patch of skin at the tip of the tail enabling the animal to use it like a fifth hand. The hands of the Spider Monkey possess no thumbs their tails allow them to grip and pick up objects. Also, the presence of a central eye area is characteristic of this group. It can be seen in the phylogenetic tree as a characteristic that differentiates the spider monkeys from the lemurs. 

Baboons(Old World Monkey/Cercopithecidae):

a.)   The Old World monkeys occupy a wide variety of environments in South and East Asia, the Middle East, Africa, and even Gibraltar at the southern tip of Spain.  Some species inhabit tropical forests, while others live on arid grasslands and even mountainous areas with heavy winter snows. There are five different species of baboons. All of them live in Africa or Arabia. Baboons generally prefer savanna and other semi-arid habitats, though a few live in tropical forests. They spend much of their time on the ground. Baboons are opportunistic eaters and, fond of crops, become destructive pests to many African farmers. They eat fruits, grasses, seeds, bark, and roots, but also have a taste for meat and will eat birds, rodents, and even the young of larger mammals, such as antelopes and sheep.

b.)  Baboons form large troops, composed of dozens or even hundreds of baboons, governed by a complex hierarchy. Males use shows of physical power to dominate rivals, and troop members spend endless hours carefully grooming one another to remove insects and dead skin. Baboons are among the most social animals and their strong social bonds are fundamental to their lives.  Baboons are usually very sexually dimorphic.  In these species, adult males are often twice as large as females and much more aggressive. These are effective weapons in defense against predators and competition with other males for mates. Females develop prominent sexual skins around the time of ovulation.  This is a signal to males that they are sexually receptive.

c.)   Although they are affected by ecological variables in similar ways as other animals, baboons are more adaptable than most and as a result have colonized a wide variety of niches across Africa. As one outcome of their ecological flexibility, they do quite well when living alongside humans.

Gibbon(Lesser ape/Hylobatidae)
 :

a.)  These acrobatic mammals, are prevalent in the dense forests of southern Asia, are perfectly adapted to life in the trees and rarely descend to the ground.. There are 15 recognized species of gibbons ranging from northeastern India to southern China to Borneo. They are all tailless, and their long coats vary from cream to brown to black. Gibbons thrive on the abundant fruit trees in their tropical range, and are especially fond of figs. They will occasionally supplement their diet with leaves and insects.

b.)  Gibbons are monogamous (a rare trait among primates) and live in family groups consisting of an adult pair and their young offspring. Adults regularly defend their territory against others of their species with piercingly loud whooping and hooting vocalizations. Also, the family will stake out a territory and defend it using loud, haunting calls that can echo for miles throughout the forest. Mated pairs, and even whole families, will sing long, complex songs together.

c.)  Some species of gibbon have even adapted large throat pouches to amplify their calls. Gibbons have long arms with sturdy rotary cup shoulder joints, comparatively short legs, permanently curved fingers, and light weight bodies.  These traits allow them to swing long distances with little effort. Their shoulder joints are even specially adapted to allow greater range of motion when swinging. They have strong, hook-shaped hands for grasping branches, comically outsized arms for reaching faraway limbs, and long, powerful legs for propelling and gasping. When gibbons walk, whether along branches or in the rare instances when they descend to the ground, they often do so on two feet, throwing their arms above their head for balance.

Chimpanzee(Great ape/Hominidae)

a.)   Chimpanzees habituate themselves to African rain forests, woodlands, and grasslands. The chimpanzee diet is usually at least 90% vegetarian.  Males are more likely to eat meat than are females, although chimp-hunting skills are relatively poor. Chimpanzees usually sleep in the trees as well, employing nests of leaves. Chimps are generally fruit and plant eaters, but they also consume insects, eggs, and meat, including carrion. They have a tremendously varied diet that includes hundreds of known foods.

b.)  Chimps are intelligent animals with generally pleasant personalities. However, the males are less peaceful than the smaller females. Chimpanzees live in fluid societies of 10-50 individuals without monogamous mating bonds.  Membership changes through time as females move from one community to another seeking new mates.  In contrast, males usually stay together in their natal community throughout their lives and act as a group in defending the food resources of their territory against incursions by other chimpanzee communities.  These interactions can be quite noisy, violent, and sometimes fatal. Chimpanzees live in social communities of several dozen animals, Females can give birth at any time of year, typically to a single infant that clings to its mother's fur and later rides on her back until the age of two. Females reach reproductive age at 13, while males are not considered adults until they are 16 years old.

c.)   Chimpanzees are comfortable walking quadrupedally on the ground in addition to climbing in trees. Chimpanzees are our closest living relatives, sharing more than 98 percent of our genetic blueprint. Humans and chimps are also thought to share a common ancestor who lived some four to eight million years ago. Although they normally walk on all fours (knuckle-walking), chimpanzees can stand and walk upright. By swinging from branch to branch they can also move quite efficiently in the trees, where they do most of their eating. Chimpanzees are one of the few animal species that employ tools. They shape and use sticks to retrieve insects from their nests or dig grubs out of logs. They also use stones to smash open tasty nuts and employ leaves as sponges to soak up drinking water. Chimpanzees can even be taught to use some basic human sign language.

Summary:

All species of primates have adapted very well to the environment in which that inhabit. Primates that primarily inhabit the canopy of forests have evolved physically to suit their environment some with prehensile tails others with rotary joints and permanently curved finger joints to enable them to swing through trees. Primates have also adapted socially, often living in large troops or families to improve their chance for survival, forever proving that there is power in numbers. Socializing within these troops and families is also a very significant aspect to the life of a primate as well. It’s interesting that the different species of primates are so scattered throughout the world and are often isolated from other types of primates, its an interesting aspect to their evolution that the different types of species with all of their physical and behavioral traits are so different from each other. This idea is proven through the fact that the environment that these primates live in drastically influences their expression of physical and behavioral traits.

Information provided by: Introduction to Physical Anthropology Course Book, National Geographic Website, Palomar.edu 

Below are images that my boyfriend and I took in Costa Rica, we were on a random hike and to our surprise, these monkeys surrounded us!! One of the coolest experiences we've ever had!!