Zoology -- Introduction to the Primates

If you are in a hurry to get information about some species of primate, click on one of the four links below to go to that section of the primate world. If you are not sure about the precise name or location of a species, use the species index to help you find what you are looking for. If you have time to read about the history of primates, the number of species and about wildlife illustrations, scroll down the page for more information. Thanks for visiting -- come back soon.

"I Didn't Come From Any Monkey!"

True enough. But you sure have a lot of relatives who did! Back in the good old days, about 30 million years ago, when we last shared a common ancestor with the Old World monkeys, there was no such thing as Monkeys, Apes or Humans as we know them today. It took all of us all those years to develop into the modern families and species that now populate much of this planet. Before then we were related to this little thumb-sized guy who lived about 45 million years ago. This fossil is a link between the earlier Prosimians and the more modern forms like us. See News Story.

How many Primate species are there today? That's difficult to say. Until recently scientists thought there might be 200-230 "good species." In 1999, Nowak's 6th Edition of Walker's Mammals of the World listed 258 living primates species (of which, four are probably extinct). In February 2000 there were announcements of 17 more new species. Conservation International estimated 310 species by May of that year. More species have been discovered since then.

Twenty-two species preceded by a green asterisk [ * ] on the following pages were described after, or too late for, Nowak 1999. Shown with a red asterisk [ * ] are 25 forms mainly considered subspecies by Nowak but given full species status by the International Union for Conservation of Nature (IUCN). Thus, I have identified 305 species in this list, and many more subspecies. No attempt is made to list all the subspecies. Almost all of those shown here are on the IUCN or USFWS lists of endangered and threatened species. There are very few primates for which there is little or no concern for their future. Their prospects are grim.

Wherever possible there are listed beside each species one or more links to information and photographs. The first one or two links usually are to species data files. Asterisks indicate at least one photo or illustration. Some foreign language sites [ *braz | *dansk | *dutch ] were selected for the superior pictures they contain. One of the wonders of the Internet is the sharing of photographs from around the world.

Family Trees Contain a Lot of Information

Family trees are also called cladograms, from the science of cladistics. They permit us to more easily visualize relationships between species, orders and classes of animals and all living things. In an ideal world these two cladograms would agree in every detail, but they don't. Scientists are not positive about the precise relationship of the Tarsiers, and they are given different positions in these two trees. How do we know where to place each group of species in a family tree and how far back in time they "branched"? Read more below.

Primata -- Cladogram after Tudge in The Tree of Life

Primate Family Tree from the Philadelphia Enquirer's Going Ape! website.

Anatomy -- Bones, Flesh and Genes

Scientists use a variety of information upon which to base cladistic trees. The distribution and age of fossils (Paleontology), and comparison of bones, muscles and internal organs (Morphology) are now joined by the study of genes (Molecular Biology) to judge the relatedness of living and fossil species. Generally speaking, however, we cannot yet use genetics for the study of very ancient fossils.

Among living species it is now possible to examine the DNA from blood, hair or tissue and accurately determine the percentage of difference between two or more specimens. Using the "Biological Clock," an estimate of the rate of mutation or genetic change over time in a family or group of animals, the data may be plotted on a graph or tree such as the one shown here. For instance, the right side of this illustration shows the percentage difference in DNA between species of Apes and Old World Monkeys. Time is shown in the horizontal dimension as millions of years before the present. For deeper discussion of family trees and cladistics see the Introduction to Evolution and Taxonomy pages (recommended for Middle School and older students).

Data from The Third Chimpanzee by Jared Diamond, 1992.

About Species and Subspecies
What is a species? It is a population of organisms (primates in this case) that does not breed with other populations of animals. All human beings are one species, Homo sapiens. What about very similar populations (or even those different in appearance) that neighbor each other but have no contact? They could be a single species having separate populations, a species having two somewhat distinctive subspecies, or they might be two species. Sometimes it is difficult to know for sure what is the case. Because there is some difficulty in knowing species lists can vary greatly. Advanced students may wish to read What is a Species, and What is Not? by Dr. Ernst Mayr, considered by many to be the dean of American Biologists and Taxonomists.

Many animals are not well studied in nature so our current lists of species depend much on the opinions of specialists who sometimes have to work with little information. One "authority" may see several species where another sees only one. You will see on the primate listings something like this:

Colobus guereza -- Abyssinian Colobus
C. g. caudatus -- Northern Black Colobus
C. g. kikuyuensis -- Colobus Colobus guereza guereza -- Abyssinian Colobus
Colobus guereza caudatus -- Northern Black Colobus
Colobus guereza kikuyuensis -- Colobus

First, notice that these two lists are identical. On the left the short form of notation is used to save space. The first name is the "nominate species." If there are any named subspecies they must be given a distinct subspecific name (the third name you see). A different specialist may think that the Northern Black Colobus is a distinct or full species and refer to it as Colobus caudatus. In some cases that subspecies might even appear as a distinct species in another genus. So, if you have difficulty finding a species here, be sure to use your browser's "find" feature (usually under "Edit" at the top of your screen) to see if the name appears in a similar nearby genus.

The last point about subspecies is that it is sometimes very difficult to see any differences between them, especially in photographs. To illustrate this point I have prepared another page on which is discussed the forms of wildlife artwork and the quality of material available on the Internet. See the pages on Primate Artwork and the photograpic comparisons of Chlorocebus Species.

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