Before you begin learning about individual primate species, you may wish to download and print out the table linked by the following button. This will help you grasp the relationships of the different species and understand which ones are evolutionarily close to us.
The order Primates consists of two suborders: the Strepsirrhini and the Haplorrhini . The strepsirhines all share the characteristic of having a moist, largely hairless nose tip (rhinarium ). This trait is shared with dogs, cats, and most other mammals that have a good sense of smell. In contrast, the haplorrhines do not have wet nose tips. Other anatomical traits distinguish these two primate suborders.
The strepsirhines were the first of the suborders to evolve. Subsequently, they are often called the "lower primates." They are also referred to as prosimians which literally means "pre-monkey" in Latin. When they were first given this name in the 19th century, it was only an inspired guess that early prosimians evolved before the monkeys. It was not until the mid 20th century that it was confirmed by the fossil record.
The strepsirhines include the lemurs, lorises, and related animals. At one time they lived in most tropical regions of the earth, including North America. Today, they are found in the wild only in the Old World. The lemurs have the most restricted range, 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. It is likely that the first lemurs on the Comoro Islands were brought there by humans.
Ruffed black and white lemur Red fronted lemur
Lemurs reached Madagascar early in primate evolution and became isolated reproductively from the African mainland about 250 miles (402 km.) away. Subsequently, they evolved into the 22 or more mostly arboreal species of today. Elsewhere, they became extinct.
The name lemur comes from an ancient Latin word, lemures, which refers to frightening spirits of the dead who haunt people at nighttime. This curious reference comes from the fact that people in Madagascar commonly believed that lemurs were ghosts. This belief was supported by their observations of lemur behavior--many of the species are only active at night and make eerie sounds.
There are five surviving families of lemurs. Species of the family Lemuridae , the true lemurs , range in size from that of a small to a large domestic cat. They have long bushy tails that are used for balancing as they jump from branch to branch. They have a well-developed sense of smell and often mark territorial limits with scent. They are herbivorous in diet, mostly eating fruit and some leaves. The larger species, such as those shown in the photos on the right, are primarily diurnal . The true lemurs are unusually sociable for prosimians. This is especially true of the ring-tailed lemurs, which form groups of up to 25 individuals and spend almost as much time on the ground as in the trees. Unlike most other primate species, lemur females generally dominate males in their social interactions.
Ring-tailed lemurs--video clip from National Geographic Society
(length = 31 secs)
The family Cheirogaleidae consists of the smallest primate species, the dwarf and mouse lemurs. When full grown, some of them are only slightly larger than mice. They are nocturnal and relatively solitary. Their omnivorous diet consists mostly of fruit and easily obtainable animal prey such as insects, frogs, and baby birds in nests. They have large ears and very sensitive hearing, which is a valuable aid in hunting in the dark.
Capture of a mouse lemur--video clip from National Geographic Society
(length = 2 mins, 49 secs)
The family Indriidae includes three groups of species: indris , avahis , and sifakas . They are the most monkey-like of all of the prosimians in that they are relatively big. The indris are the largest in size, reaching nearly four feet from head to toe with their legs extended and weighing up to 21 pounds (9.5 kg.). During the early evening, Indris proclaim their territories in the tree tops with loud, piercing vocalizations. By doing this, they space themselves out in the forest. They are also distinctive in having only a vestigial tail. The sifakas have long spring-like legs that allow them to jump dramatically over 30 feet (9 m.) from tree to tree. This evolutionary specialization of their legs forces them to hop rather than walk when on the ground.
Searching for sifakas--video clip from National Geographic Society
(length = 3 mins, 47 secs)
Aye-aye Aye-aye hand
The extremely rare aye-aye is the only surviving species of the family Daubentoniidae . They are not often seen because they live solitary lives mostly in forest trees, make little noise, and are nocturnal. They have unusual hands and teeth for primates. Their elongated, narrow fingers have claw-like compressed nails that are used, along with their long, curved, rodent-like incisor teeth, to get at grubs under tree bark and other hard to reach delicacies such as coconut meat. While they are primarily carnivorous, their prey only includes such things as insects, eggs, and newly hatched birds.
More than half of the lemur species are on the verge of extinction due to habitat destruction. Their forests in Madagascar have mostly been burned down by impoverished farmers seeking new farmland and wood to make charcoal for cooking. Lemurs are also commonly captured to be pets and killed to provide restaurant delicacies.
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O'Neil. All rights reserved.