Is The Animal In Figure 9.15 A Primate? How Do You Know?
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| Ring-tailed lemurs | |
The o rder Primates 
includes humans, apes, monkeys, and prosimians. Many of them may exist familiar, but it would not exist surprising if yous cannot immediately visualize prosimians (like the ring-tailed lemurs in the picture on the correct) .
How many living primate species be today is not clear. The number varies depending on whether closely related groups are considered to exist varieties of each other or distinct species. Some taxonomic splitters classify up to 350 species, while lumpers include as few every bit 190. Most estimates are in the range of 230-270. This ambiguity may be partly resolved in the future with DNA sequencing data. Compounding the problem is the fact that every few years new species of primates are found. The tropical forests of South America, Africa, and Southeast Asia may withal be hiding ones that are unknown to the scientific earth. However, information technology is likely that all major groupings of primates have been discovered.
Mwhatsoever primate species are now in danger of becoming extinct. The master cause is deforestation, driven ultimately by human population growth. Additional pressure is placed on primate populations past humans hunting them to sell for food and pets. Monkeys and apes are popular sources of "bush meat" in Westward Africa. At to the lowest degree 22 species of primates and many other kinds of wildlife are being hunted in Africa for this purpose. Despite the fact that the auction of "bush meat" is outlawed in well-nigh countries, it is at present beingness sold illegally in Europe and North America. In recent years, it could be bought at stores that cater to African immigrants in Paris, New York, Chicago, San Francisco, Montreal, and some other major cities.
Today, not-man primates are express in their natural habitats primarily to the tropical and subtropical regions of the New and Old Worlds. They take never lived in Australia and most of the islands in the Pacific ocean. However, the earliest primates also lived in Northward America and Europe beginning around 55-50 one thousand thousand years ago.
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| Natural range of non-human primates |
General Characteristics of Primates
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| Lowland gorilla |
Primates are surprisingly variable in size. They range all the way from the pygmy mouse lemur that weighs less than 2 ounces (55 g.) and can fit in the palm of your manus to the gorilla that grows to as much as 440 pounds (200 kg.) in the wild and even heavier in captivity. Even so larger primates existed in the past but are at present extinct.
Primates are generally lively, clever, and very successful at adapting to unlike environmental opportunities. Physically, however, they are relatively unspecialized compared to animals such as birds, horses, and cats. Primates are not especially fast runners, they do not accept the sharpest hearing, they cannot fly, nor are they efficient hunters.
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| Spider monkey Count the number of fingers... | |
With the exception of spider monkeys, all of the primates take retained the aboriginal mammalian trait of pentadactylism , which is having 5 fingers on each hand and five toes on each foot. An increasing refinement of the hands and anxiety for grasping objects has been a hallmark of primate evolution. Their fingers and toes are mobile and accept very sensitive tactile pads at the tips, unlike well-nigh other mammals. At least some digits on all primates also accept flat nails in place of rigid claws. This makes the manipulation of bits of food and other objects much easier.
The grasping, or prehensile , power of primate hands varies significantly as well with the caste of opposability of the thumb. Partially rotating the thumb and pressing information technology forcefully towards the fingers provides a secure grip for hanging on branches and for manipulating small objects. All primates, with the exception of humans, have prehensile feet in addition to hands. However, few have the loftier caste of thumb opposability and strength typical of humans.
The small New World monkeys called marmosets and tamarins usually hang onto a tree branch by pressing against information technology with their palms and using all of their aptitude fingers together as counter pressure in a claw-like power grip. The more dexterous monkeys and apes can also use a secure ability grip formed past the partial flexion of the fingers and the palm with counter force applied by the pollex. Humans and some apes likewise can apply precision grips formed past pinching with the tips of their flexed forefingers and the thumb. This allows their easily to exist used effectively for manipulating small objects, such every bit the fork in the hand of the chimpanzee shown below.
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| Claw-similar ability grip | Precision grip | |||
| Secure power grip |
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| Upright posture (lowland gorilla) |
All primates accept a marked tendency towards erectness in their upper bodies. This can exist seen in their sitting and standing postures likewise as occasional bipedalism . They also have shoulder joints that are unusually flexible for mammals. This is due to secure ball joints and stiff clavicles , or collarbones, which take allowed them to use their arms very effectively in climbing copse. Clavicles are another ancient mammalian trait that primates have retained.
In primate evolution, there was a progressive reduction in olfactory organ size and in the olfactory areas of the encephalon. Lemurs are an exception. They are very much like the early primates 50 meg years ago. Note the marked departure between lemur, monkey, and man noses in the photos below. Most monkeys and apes have evolved relatively modest noses like the states, while lemurs have retained long snouts similar to foxes and raccoons. Information technology is non surprising that lemurs have a comparatively good sense of scent.
Almost mammals have about the aforementioned number of genes that code for odor receptors in their nasal tracks. Withal, the majority of these genes in humans, and presumably other big primates, are no longer functional. Contempo enquiry has shown that of the approximately 1,000 human olfactory receptor genes, but 347 remain functional. The rest have mutations that deactivate them. Does this really mean that people have a poor sense of smell? The answer is both aye and no. We are poor at sensing brusque-chain chemic compounds just good at discriminating between complex long-chain ones such as those of many foods and flowers. Dogs are just the opposite in this. However, the smelling ability of dogs is far superior to people in ane way. Fewer molecules of a substance are commonly needed for dogs to detect it.
As the primate nose progressively shrank in size over millions of years, there was a corresponding increment in visual capabilities. Equally much as l% of the cerebral cortex in some species of monkeys is involved in visual 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 (three-D) depth perception or stereoscopic vision. At the same time, the field of view for peripheral vision was reduced.
| | Human eyes accept an overlapping field of view of nigh 120�. It is but in this field that we take stereoscopic vision. Beyond this 3-D area out to 160-180�, we see things only in ii dimensions (2-D)--i.e., flat without depth. Monkeys and apes have about the aforementioned depth perception ability every bit humans, simply the eyes of lemurs are farther apart resulting in a smaller overlapping field of view. | |
Depth perception is an invaluable tool for animals that need to move chop-chop. It allows them to estimate the distances to of import objects in their environs. For monkeys jumping from branch to branch high upwards in the canopies of forests, this is a matter of life and death. Likewise, accurate depth perception is a disquisitional adequacy for hunters, such as cats and hawks, who need to accurately judge distances in the pursuit of their prey. In contrast, information technology is often preferable to take greater peripheral vision if you lot are the casualty. Gazelles, rabbits, and chickens have most a 360� field of view, only relatively niggling of that is stereoscopic vision.
Compared to most other animals, primate brains are large relative to their torso size. Those areas of the brain that are involved with controlling manual dexterity, eye-mitt coordination, and stereoscopic vision have specially expanded. These traits were probably selected by nature mostly due to their usefulness in traveling in copse, manipulating objects, and getting food.
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| Note: primates in modern zoos often alive longer than the life spans listed here because of the medical care that they receive. | |||||||||||||||
The more than capable uterus and placenta of primates back up long gestation periods, or pregnancies, for animals of their size. For instance, the mouse lemur has a gestation flow of 60 days, but information technology is only 20 days for a comparable size rodent mouse. One thousand acaques, which are one of the most common groups of monkey species in the Old World, have 13.5-15.5 week gestations. Among comparable size domesticated dogs, it is only about nine weeks. The result of long gestations is that offspring are built-in more mature and, therefore, have a greater chance of survival. Primate mothers besides are generally very protective and nurturing with their young. Later on, primates do non demand to take many offspring to maintain their population numbers. Multiple births at whatsoever one fourth dimension are rare for them. The time gap betwixt generations is surprisingly long for the larger primates. Among humans today, parents are on boilerplate 29 years older than their children. Past comparison, chimpanzee mothers are on average 25 years older than their offspring. Among female gorillas, it is 19.3 years.
At that place oft is a correlation betwixt trunk size and longevity in the animal kingdom. Species with larger bodies by and large alive longer. All the same, primates have unusually long natural life spans for their size. For instance, mouse lemurs live about eight years. Rodent mice rarely reach two years. Rats, which are slightly larger than mouse lemurs, can live iii years. Large monkeys, such as baboons, live upwardly to 30 years. Male baboons can weigh as much every bit 90 pounds. Comparable size domesticated dogs have a life expectancy of just 10-12 years. With good medical care, chimpanzees tin live nearly as long as people (50-75+ years). This is not surprising given that they are anatomically very like to the states. Enquiry done past Herman Pontzer of Hunter College suggests that the unusual longevity of primates is due to the fact that they expend only 50% as many calories a 24-hour interval compared to other animals their size. Slower metabolism rates are associated with slower rates of growth, reproduction, and aging in mammals.
Near primates have adapted to an arboreal , or tree living, way of life. Even the terrestrial ones unremarkably slumber in the trees. The most notable exceptions are humans and gorillas. Both of these species live on the footing with occasional tree climbing for fun, particularly by children. Well-nigh all primates are diurnal , which is to say, they are active during the solar 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 add-on, they regularly groom each other, thereby keeping clean and satisfying psychological needs at the same fourth dimension. Grooming is a very pleasurable activity for primates, including humans. It is important to note that the few nocturnal primate species are the least social.
Primates have been very successful animals due largely to the fact that they are intelligent and opportunistic in getting food. Most are unusually adaptable in nutrition. This has tremendous evolutionarily selective value. Many species are omnivorous , though vegetable foods commonly make up the bulk of calories consumed by most primate species considering they are easier to obtain. By comparison, animals such equally koalas and giant pandas are by and large 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 behemothic pandas primarily swallow the shoots of a small number of bamboo species. If these food sources are not available, koalas and behemothic pandas die. Not surprisingly, their highly express range of foods restricts where they can live. This is not the case with many primate species.
Are Primates Good Pets?
Often people who have not had the responsibility of taking care of a monkey or ape in captivity call up that they would be great pets. After all, they are beautiful when they are youngsters and remarkably human-similar. However, they generally make very poor pets. As one monkey owner said "People find out when it's besides late. After six months, they're similar a two twelvemonth-sometime that can fly." Because they are intelligent, very agile, sometimes unpredictable, and easily bored, they frequently become into trouble when left alone. In improver to being destructive, most are as messy as homo babies. Unlike humans, all the same, they remain this way all of their unusually long lives. Owning large apes in particular is a lifelong delivery that takes considerable patience, free energy, and money. Male chimpanzees can be surprisingly violent in their interactions with each other and humans. In contempo years, several people have been extensively maimed and even killed by their pet chimpanzees in the U.Southward.
Copyright (C) 1998-2014 by Dennis O'Neil. All rights reserved.
illustration credits
Source: https://www2.palomar.edu/anthro/primate/prim_1.htm
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