Fun Facts About Finger Monkeys, World's Smallest Living Primates

Size of a baby finger monkey
The finger monkey is one of the tiniest living primates in the world. Otherwise known as pygmy marmosets, these small monkeys are now raised as exotic pets.
Pygmy marmosets/finger monkeys are the world's tiniest true monkeys. A fully grown finger monkey weighs approximately 4 - 5 ounces, and grows to a maximum 6 inches in length (excluding the tail)!
These lilliputian primates have their own special genus, since they are different from the other marmosets. Their behavior in natural surroundings is more exuberant than when they are held in captivity.

Why the Name 'Finger Monkey'?

From the very name, it can be inferred that they are small in size. Most of their photographs show these tiny animals clinging to human fingers and gazing innocently with their wide eyes. However, this tiny creature won't fit onto your finger as it grows. Adult monkeys may have a body length of 5 to 6 inches, excluding a tail length of around 8 inches.

Being the smallest monkey in the world, this animal is also known as pocket monkey. Finger monkeys (Cebuella pygmaea) are, as a matter of fact, pygmy marmosets. They are also known by the names 'little lion' or 'tiny lion'. A finger monkey gets the first part of its name since it is only finger-sized in length, and also because this cute little primate hugs and grips on to your finger tightly.

General Information

Kingdom Animalia
Phylum Chordata
Class Mammalia
Order Primates
Family Callitrichidae
Genus Cebuella
Species C. pygmaea

Geographic Range - Native to South America. Found in Columbia, Ecuador, Brazil, Peru and Bolivia.

Habitat - Lives in rainforests, secondary forests as well as moderately distributed forests with proximity to water sources.

Conservation Status - Least Concern

Nomenclature - Cebuella pygmaea (Binomial Name)
Also known as Pygmy Marmoset, Finger Monkey, Mono de Bolsillo (Pocket Monkey).

Some Interesting Facts
  • An adult finger monkey has a furry body, generally tawny colored with black flecks. Its underbelly, however, is either cream or white in color.
  • This primate sports a mane-like fur around its head which resembles a lion's mane (that's why they are also called 'tiny lion'). Their eyes are almond-shaped.
  • The black-ringed tail forms a major portion of its 13-14 inch long body. The head and body together measure only about 5 inches. However, its tail can grow up to 8 - 9 inches.
  • The finger monkey is fully grown by the time it is two years old. But they attain sexual maturity comparatively early between 12 - 16 months.
  • Males of this species are heavier, weighing up to 5 oz, as compared to females who generally weigh a little over 4 oz. Except for the difference in height and weight, both the sexes share the same physical appearance.
  • The lifespan of finger monkeys in captivity and in the wild differs. The average lifespan is 12-16 years; however, it goes up to 20 - 22 years in captivity, and some have been known to have lived up to 25 years.
  • It uses its sharp claws to move between the bigger branches or move up on trees. It spends most of the day making inch-deep holes in the bark of trees with the help of sharp, lower incisors. It keeps returning to the holes to gather and eat gum produced by the trees. However, when the food source dwindles, it shifts to another area.
  • Finger monkey diet includes leaves, nectar of flowers, fruits, insects, spiders, small lizards, and sometimes, small reptiles. Food habits also include drinking plant sap and eating gum from trees.
  • These monkeys are highly social animals. In the wild, they live in groups of 6-10, made of an adult pair and their offspring. Interestingly, these creatures are monogamous.
  • Within the group they communicate by body language, scent marking, making high-pitched sounds, and grooming each other.
  • A female finger monkey can give birth every 5 months. Usually, the breeding female may give birth to a single offspring, or even to twins, triplets or quadruplets, after around 135 days of gestation. The newborn weighs about ½ ounce. The father looks after the offspring for a couple of weeks after birth, and is ably supported by the older offspring in the group.
  • It is vulnerable to cats, snakes and birds of prey. When threatened, they resort to either vocalizing, chasing or keeping still, till the danger passes.
  • Although this species is not endangered, loss of habitat is a serious concern.
  • Pygmy Marmosets can produce ultrasonic cries inaudible to humans. These cries are generally used to show antagonism.
Finger Monkeys as Pets

It is not advisable to keep these monkeys as pets. Looking after a finger monkey can be an expensive affair. They need lots of attention. Like other primates, this monkey is not well-behaved initially; it has to be trained. Habits that a finger monkey learns in the first two years will stay with it throughout its life. You should be able to devote considerable time and patience to your marmoset. They are social animals and prefer to live in groups. So, it is always better idea to let them live in their natural habitat.

If you still wish to buy one, you need to check whether adopting a finger monkey is legal in your state. If there are no legal issues involved, you can search for breeders on the Internet. You can also look for pet owners who may wish to give away their finger monkeys for adoption. If you find one, you may be able to strike a good deal. If you're planning to purchase from a pet store, make sure your prospective pet is disease-free and vaccinated. There are a couple of other important things you need to look into, like the rather complex diet of marmosets and difficulty in successfully finding a veterinarian trained in primate care close to your house. Both these things are essential and cannot be neglected.

Although they look really harmless and adorable, finger monkeys are known to be generally on the aggressive side. They have long sharp teeth and claws which can nip painfully! If you have small children and other pets in your home, read up and understand all you can about this primate before you choose to get one, and be doubly sure you can handle your new pet!
Wild Marmoset Monkey
Marmoset Portrait