The Primates compiled by Dana Visalli A male Mandrill Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment. Most primate species remain at least partly arboreal. There are a surprisingly large number of primates, or ‘monkeys and their kin.’ The total number is variable, but settles in the range of approximately 325 species. The word ‘primate’ comes from a Latin root meaning ‘first rank’ or ‘numeral uno,’ a reflection of ever-present an- thropocentrism (human self-centeredness) of our species, which tends to judge nearby Homo sapiens (which means ‘wise man’) as the pinnacle of the infinitely long evolutionary journey, while those Homo sapiens at a distance are often considered to be ‘the other’ and ‘the enemy’ and therefore not wise at all. Primates range in size from a tiny lemur in Madagascar called Madame Berthe’s Mouse Lemur, which weighs one ounce, to the lowland gorillas in Africa, which weigh in at well over 400 pounds. Genetic studies indicate that the primate line originated about 85 million years ago, in the mid-Cretaceous Peri- od. New primate species are still being discovered. More than 25 species were taxonomically described in the decade of the 2000s and eleven have been described since 2010. Primates are characterized by large brains relative to other mammals, as well as an increased reliance on stereoscopic vision at the expense of smell, the dominant sensory system in most mammals. These features are more developed in monkeys and apes and noticeably less so in lorises and lemurs. Most primates have opposable thumbs and some have prehensile tails. Many species are sexually dimorphic, meaning males and females are markedly different in size; in primates males are typically larger than females (in contrast to raptors, in which females are typically larger). Depending on the species, adults may live in solitude, in mated pairs, or in groups of up to hundreds of members. Many primate species are now in danger of becoming extinct. The primary cause is deforestation, driven ultimately by human population growth and over-consumption of the Earth’s resources. Additional pressure is placed on primate populations by humans hunting them to sell for food and pets. Monkeys and apes are popular sources of ‘bush meat’ in Africa. Dana Visalli/[email protected]/www.methownaturalist.com Today, non-human primates are limited in their natural habitats primarily to the tropical and subtropical regions of the New and Old Worlds. They have never lived in Australia and most of the islands in the Pacific Ocean. However, the earliest primates also lived in North America and Europe beginning around 55-50 million years ago. In primate evolution, there was a progressive reduction in nose size and in the olfactory areas of the brain. Lemurs are an exception; they are very much like the early primates 50 million years ago. As the primate nose progressively shrank in size over millions of years, there was a corresponding increase in visual capabilities. As much as 50% of the cerebral cortex in some species of monkeys is involved in visu- al processing. Many primates have color vision comparable to our own. All have binocular vision with fields of view that significantly overlap, resulting in true three dimensional depth perception or stereo- scopic vision. At the same time, the field of view for peripheral vision was reduced. Compared to most other animals, primate brains are large relative to their body size. Those areas of the brain that are involved with controlling manual dexterity, eye-hand coordination, and stereoscopic vi- sion have particularly expanded. These traits were probably selected by nature mostly due to their useful- ness in traveling in trees. Most primates are diurnal, which is to say, they are active during the day and sleep at night. Generally, primates are highly social animals. Most of their waking hours are spent socializing with each other. This is made easier by complex vocalizations and visual displays. In addition, they regularly groom each other, thereby keeping clean and satisfying psychological needs at the same time. Grooming is a very pleasurable activity for primates, including humans. Primates have been very successful animals due largely to the fact that they are intelligent (have relative- ly flexible behavior; they are not completely dominated by genetic programming) and are opportunistic in obtaining food. Many species are omnivorous, though vegetable foods usually make up the bulk of calories consumed by most primate species because they are easier to obtain. By comparison, animals such as koalas and giant pandas are generally less successful because they are extremely limited in the kinds of foods that they can or will eat. Koalas subsist on the leaves of a few species of eucalyptus, and giant pandas primarily eat the shoots of a small number of bamboo species. If these food sources are not available, koalas and giant pandas die. Not surprisingly, their highly limited range of foods restricts where they can live. This is not the case with most primate species. Families of Primates 1. Dwarf & Mouse Lemurs- Family Cheirogaleidae ('genus name'): 34 species. This family lives exclusively on the island of Madagascar; they are the smallest of the primates. Dwarf and mouse lemurs are nocturnal and arboreal. They are excellent climbers and can also jump far, using their long tails for balance. When on the ground (a rare occurrence), they move by hopping on their hind legs. They spend the day in tree hollows or leaf nests. They are typically solitary, but sometimes live together in pairs. They are omnivores, eating fruits, flowers, leaves and Madame Berthe’s Mouse Lemur sometimes nectar, as well as insects, spiders, and small vertebrates. Madame Berthe's mouse lemur (Microcebus berthae) is the smallest of the mouse lemurs and the smallest primate in the world; the average body length is 9.2 cm (3.6 in) and seasonal weight is around 30 g (1.1 oz). It was discovered in 1992 2. Lemurs- Family Lemuridae (Latin, 'spirits of the dead'): 21 species. This is one of five families commonly known as lemurs, all native to Madagascar. These animals were once thought to be the 2 evolutionary predecessors of monkeys and apes, but this is no longer considered correct. Lemurids are medium-sized arboreal primates, ranging from 32 to 56 cm (12-22 in) in length, excluding the tail, and weighing from 0.7 to 5 kg (1.5-11 lbs). They have long, bushy tails and soft, woolly fur of varying coloration. Most species are highly agile, and regularly leap several metres between trees. 3. Sportive Lemurs- Family Lepilemuridae ('pretty lemur'): 26 species. Ring-tailed Lemur Medium sized primates living only in Madagascar. They are strictly nocturnal, predominantly arboreal, and eat primarily leaves. They got their name from their leaping abilities. 4. Woolly Lemurs & Sifakas- Family Indriidae: 19 species. All species are arboreal, though they do come to the ground occasionally. When on the ground, they stand upright and move with short hops forward, with their arms held high. In the trees, though, they can make extraordinary leaps and are extremely agile, able to change direction from tree to tree. Like Sportive Lemur most leaf eaters they adjust for the low nutrient content of their food by long rests. Often they can be seen lying stretched on trees sunning themselves. Indrids live together in family federations from 2 to 15 animals, communicating with roars and also with facial expressions. Indrids are herbivores, eating mostly leaves, fruits and flowers. 5. Aye-Aye- Family Daubentoniidae: 1 species. The aye-aye (Daubentonia madagascariensis) is a lemur, a native to Madagascar that combines rodent- Silky Sifaka (critically endangered) like teeth and a special thin middle finger to fill the same ecological niche as a woodpecker. It is the world's largest nocturnal primate, and is characterized by its unusual method of finding food; it taps on trees to find grubs, then gnaws holes in the wood using its forward slanting incisors to create a small hole in which it inserts its narrow middle finger to pull the grubs out. It is currently classified as Endangered, and a second species, Daubentonia robusta, appears to have become extinct at some point within the last 1000 years. A full-grown aye-aye is typically about three feet long with a tail as long as its body Aye-Aye 6. Lorises & Pottos-Family Lorisidae: 28 species. Lorisids live in tropical, central Africa as well as in south and southeast Asia. The are slim, nocturnal, arboreal primates that are either solitary or live in small family groups. The main diet of most lorisids consists of insects, but they also consume bird eggs and small vertebrates as well as fruits and sap. 7. Galagos- Galagidae: 19 species. Also known as Bushbabies. Small, Red Slender Loris nocturnal primates of Africa only. According to some accounts, the name "bush baby" comes from either the animal's cries or its appearance. Galagos have large eyes that give them good night vision, strong hind limbs, acute hearing, and long tails that help them balance. Their ears are batlike and allow them to track insects in the dark. They catch insects on the ground or snatch them out of the air. They are fast, agile creatures. As they bound through the thick bushes, they fold their delicate ears back to protect them. They have nails on most of their digits, except for the second toe of the Garnett’s Galago 3 hindfoot, which bears a 'toilet' claw for grooming. Their diet is a mixture of insects and other small animals, fruit, and tree gums.