Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as the simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes, which constitutes an incomplete paraphyletic grouping; however, in the broader sense based on cladistics, apes (Hominoidea) are also included, making the terms monkeys and simians synonyms in regards to their scope.[citation needed][3]
In 1812, Geoffroy grouped the apes and the Cercopithecidae group of monkeys together and established the name Catarrhini, "Old World monkeys", ("singes de l'Ancien Monde" in French).[3][4][5] The extant sister of the Catarrhini in the monkey ("singes") group is the Platyrrhini (New World monkeys).[3] Some nine million years before the divergence between the Cercopithecidae and the apes,[6] the Platyrrhini emerged within "monkeys" by migration to South America from Afro-Arabia (the Old World),[citation needed][7][8] likely by ocean.[9][10][better source needed] Apes are thus deep in the tree of extant and extinct monkeys, and any of the apes is distinctly closer related to the Cercopithecidae than the Platyrrhini are.
32
Most monkeys have the same number of teeth as humans do: 32, with 16 on top and 16 on bottom. However, the type of teeth depend on a monkey's location. Old World monkeys (meaning those who live in Africa or Asia) have 12 molars, eight pre-molars, four canines, and eight incisors, just as humans do.
Do monkeys sleepwalk?
Second, somnambulism does not exist in non-human primates including apes (chimpanzee, gorilla, orang-utan and gibbon); and thus, it is a unique behavioral disorder present only in humans.
Do monkeys cry in pain?
Monkeys, apes and other simians have nothing quite like our tears. They have tear ducts to help keep their eyes lubricated and clean. But they don't drain when they're sad. Chimps will scrunch up their faces and make noise when they're in distress, but they don't connect the tears and the wailing.7
Credits:
Created with images by LP2Studio - "Portrait of a Rhesus macaque monkey in Guilin, Guangxi province, China" • LP2Studio - "Portrait of a Rhesus macaque monkey in Guilin, Guangxi province, China" • peter - "squirrel monkey portrait" • Cheryl Ramalho - "Portrait of a gray-shanked douc langur (Pygathrix nemaeus), an endangered species of monkey native to Vietnam. A dark background for copy space." • hit1912 - "Long-tailed macaque monkey jumping in the wild" • wollertz - "white faced or capuchin monkey" • Vlad - "The rhesus macaque monkey (Macaca mulatta), Nanwan Monkey Island, China" • Vlad - "The rhesus macaque monkey (Macaca mulatta), Nanwan Monkey Island, China" • buunature - "Howler monkey sitthing in a tree in the Costa Rica Junge/rainforest" • Photocreo Bednarek - "Chimpanzee monkey portrait on black" • serge - "White-faced Capuchin monkey hanging upside down from a liana, Cahuita, Costa Rica"