What is the largest monkey?

Answer 1

The Mandrill (Mandrillus sphinx) is a primate of the Cercopithecidae (Old-world monkeys) family, closely related to the baboons and even more closely to the Drill. Both the Mandrill and the Drill were once classified as baboons in genus Papio, but recent research has determined that they should be separated into their own genus, Mandrillus. The Mandrill is the world's largest monkey species. The word mandrill means "man-ape".
The Mandrill is recognized by its olive-colored fur and colorful face and rump amongst males, a coloration that grows stronger with sexual maturity; females have duller colors. This coloration becomes more pronounced as the monkey becomes excited. The coloration on the rump is thought to enhance visibility in the thick vegetation of the rainforest and aids in group movement.
Males can weigh up to 60 lb (30 kg), females about half as much. They can grow to be about 1 m long (39 in) and can survive up to 25 years in captivity. Females reach sexual maturity at about 3.5 years.
The Mandrill is found in the tropical rainforests of southern Cameroon, Gabon, Equatorial Guinea and Congo. Its distribution is bounded by the Sanaga River to the north and the Ogooué and Ivindo rivers to the east. Recent research suggests that mandrill populations north and south of the Ogooué river are genetically so different as to be different sub-species.
Mandrills are social creatures and may be found in groups of up to 800 individuals, mostly females and young led by a dominant male. Most adult males are solitary. It is impossible to accurately estimate group size in the forest; filming a group crossing a gap between two forest patches or crossing a road and playing back the tape at slow speed is the only reliable way of estimating group size. The largest group verifiably observed in this way contained over 1300 individuals, in Lopé National Park, Gabon - the largest aggregation of non-human primates ever recorded.
The Mandrill is an omnivore and acquires its food by foraging (mainly plants, insects and smaller animals) from the ground as it is terrestrial. Its main natural predators are leopards.
A large group of mandrills can cause significant damage to crops in a very short time, and where common they are widely perceived as pests.
Mandrills are hunted for food throughout their range, either with guns or using dogs and nets. In Cameroon, habitat loss to agriculture is also a threat.
Although the Mandrill does not normally hunt larger prey, males have been observed to hunt and consume duiker (a small antelope).

Answer 2

The Mandrill monkey which is related to the baboon has the distinction of being the world's largest monkey as far as species go.

Answer 3

baboon Papio sp.
http://www.sandiegozoo.org/animalbytes/t-monkey.html

Answer 4

king kong a.k.a gorillla