The biological order of primates includes humans, apes, and monkeys. It also includes prosimians, which are smaller, more primitive animals that we recognize as cute enough to be our relatives.
1. Potto
The potto (Perodicticus potto) is only found in the tropical forests of equatorial Africa. They live in trees and eat ants and other insects. The potto is distinguished from the loris by its neck bones, which form a sort of shield over its back. These nocturnal animals have a brush of cartilage under their tongues, which they use to clean their teeth.
2. Galago
Primates of the family Galagidae are called bush babies or galagos. Bush babies, native to sub-Saharan Africa, will eat anything from tree sap to snakes. They can turn their heads 180 degrees, completely to their backs! The name bush baby comes from the cry of the galago which sounds like a human baby. They are so cute that some people keep them as pets, which is not recommended as they are nocturnal animals and need a large territory. Image by Flickr user Joachim S. Müller.
3. Lemurs
The many species of lemurs consist of several families of primates native to Madagascar. The ring-tailed lemur (Lemur catta) is the species we are most familiar with, as it is one of the few prosimian species that is active during daylight hours, and because they will readily reproduce in zoos. However, the species is classified as vulnerable due to habitat destruction. Sifaka lemurs (Propithecus candidus) gave us the term "leapin' lemurs", as you can see in this video. Image by Flickr user Adrian Stewart (Chortler).
"They're gentle, well mannered, and pretty and yet great fun . . . I should have married one." -John Cleese
4. Slender Loris
The gray slender loris (Loris lydekkerianus) and the red slender loris (Loris tardigradus) are two of several species of slender loris found in tropical Asia, particularly in India and Sri Lanka. They eat mostly insects, but will also eat leaves, eggs, and slugs. Slender lorises have traditionally been considered to have magic or medicinal powers, which has contributed to their decline. Although the number of slender lorises is hard to pin down, they are considered endangered.
5. Slow Loris
There are three species of slow loris (Nycticebus) and all are native to south Asia, from India to the Philippines. Slow lorises are carnivores that eat birds, eggs, shellfish, insects, and reptiles. Although slow lorises are unbelievably cute, as many found out by watching this video, they do not make good pets. They exude a toxin from their elbows which they deliver by biting, and are illegal to import in most countries.
6. Aye-aye
You may be familiar with the Aye-aye (Daubentonia Madagascariensis) from pictures that are presented as a "what is it?" It is hard to recognize as a primate, but has opposable thumbs and is a type of lemur. Aye-ayes are found in Madagascar, where they are considered a bad omen by natives and often killed on sight, which contributes to their status as near-threatened. Aye-ayes are omnivores and will steal food from villages, which may have contributed to their reputation. Of course, it may be because of the way they look, which can be hideous or adorable depending on who is looking. Pictured is Kintana, an aye-aye born at the Bristol Zoo Gardens in 2005.
7. Tarsier
Tarsiers (Tarsiidae) were once found in Europe, North America, and Africa according to fossil records, but are now restricted to the islands of Southeast Asia, such as Borneo and the Philippines. It stands out among prosimians for its large eyes, which can each weigh as much as its brain. Tarsiers are nocturnal, live in trees, and eat insects, birds, and reptiles. If an owl were a mammal, it would be a tarsier. All tarsier species are threatened, and two are classified as endangered. Image by Flickr user chaosandcreations.
8. Marmoset
Marmosets (Callitrichidae) are classified as New World monkeys, but are so small I had to include them in this list. There are 25 species of marmosets that average around eight inches long, not including the tail. The pygmy marmoset is the world's smallest monkey at about six inches, with a tail twice as long as its body. Marmosets almost always give birth to fraternal twins, and are the only animal known to display germline chimerism, meaning they can carry the sperm or ovum of their fraternal twin, which has different DNA from their own. Image by Flickr user CzechR.
9. Berthe's Mouse Lemur
With a body only about four inches long, Berthe's Mouse Lemur (Microcebus berthae) is thought to be the world's smallest existing primate. This lemur is found only in Madagascar, and only in a small (900 square km) area south of the Tsiribihina River in Kirindy Mitea National Park. It resembles a mouse except for its forward-facing eyes. It will eat insects, fruit, and small reptiles, but prefers a sweet secretion exuded by a native insect during its larval stage. With an estimated population of only 8,000, efforts are being made to turn Berthe's Mouse Lemur's native habitat into a strict conservation zone.