Fingernail impression from the hand of a macaque.
Primates have ‘human-like’ short, flat fingernails!

Did you know that far most primates have ‘human-like’ short, flat fingernails? Except for marmosets and tamarins, all primates have flat fingernails and toenails instead of claws. What are the major differences between the hands of primate species and the human hand?

• 1 – Primates usually have a shorter thumb than humans – the thumb of the macaque (see photo on the left) does not rearch out behond the distal border of the handpalm.

• 2 – Primates usually have a lower ‘2D:4D digit ratio’ than humans – the hand of the macaque is featured with a much longer ring finger (digit 4) than the pointer finger (digit 2).

• 3 – Primates usually have more fingerprint- and palmar whorls than humans – the hand of the macaque is featured with 5 palmar whorls.

• 4 – Primates always have a lower ‘ridge density’ than humans.

• 5 – Primates usually have (various) palmar transversal hand creases, a.k.a. ‘simian lines’ – the hand of the macaque has one ‘simian line’.

SUGGESTIONS FOR FURTHER READING:
PRIMATE HANDS – Finger length linked with social behavior!
Understanding our past: the human hand vs. the primate hand!
The Monkey Palmist!
Hands in the perspective of evolution!
More interesting stories about the hands of primates!

PHOTO: Impression from the hand of a chimpanzee:
Impression from the back of the hand of a macaque.

Advertisements