Stump-tailed macaques were studied to examine the source of their SA.

Adult stump-tailed macaques, in fact, are commonly used in laboratories for the testing of hair-regrowth treatments.

Some other primates, such as chimpanzees, stump-tailed macaques, and South American uakari show progressive thinning of the hair on the scalp after adolescence.

Stump-tailed Macaque (Macaca arctoides)

Stump-tailed macaques - There are 11 of these primates at Monkey World and are affectionately called the "Ugly Monkeys".

The park is home to 152 smaller primate species, which make up the capuchin monkeys, common marmosets, stump-tailed macaques, woolly monkeys, cottontop tamarins, patas monkeys, ring-tailed lemurs and squirrel monkeys.

It houses the largest number of stump-tailed macaques in Malaysia, which is thirteen, compared to six at the National Zoo of Malaysia (Zoo Negara) and five at the Malacca Zoo.

Prostaglandin F2α (PGF2a) analogues induces hair regrowth in animal models of androgenic alopecia with transgenic mice, and stump-tailed macaques, and initially generated 'great expectations' in pharmaceutical research for potential effectiveness in alopecia.

These include the globally vulnerable Pig-tailed Macaque, Assamese Macaque, Stump-tailed Macaque and White-cheeked Crested Gibbon (Nomascus leucogenys and Nomascus leucogenys siki).

But escape to Ko Chang's mountainous interior and you'll find a lost world of rugged waterfalls and impenetrable jungle filled with a Noah's ark of wildlife, including stump-tailed macaques, small Indian civets and reticulated pythons.