Why Is a Mammal Covered in Scales? Armour Made of Hair

The plates covering the animal are made of keratin, the same protein that forms hair, claws, horn and fingernails, which makes them fundamentally different from the scales of a fish or a reptile despite looking comparable. They grow continuously from the skin and are worn down at the edges. They overlap like roof tiles, are attached at the base and free at the edge, and are sharp enough to cut. Rolling into a ball presents nothing but scale to an attacker and protects the soft underside entirely, which defeats nearly every predator the animal faces, since even a lion cannot open one. Hair grows between the scales on the underside and the face.

The whole animal is built around eating ants and termites:

• •No teeth at all, which is unusual even among specialist insect eaters
• •A tongue longer than the body, anchored near the pelvis rather than in the mouth
• •Enormous salivary glands producing sticky saliva
• •Powerful front claws for opening nests, so long the animal walks on its knuckles
• •A muscular stomach containing swallowed grit that grinds the food
• •The ability to close the nostrils and ears against defending insects

The animal is described as the most trafficked wild mammal in the world, with estimates of over a million taken in a recent decade, and the demand has two components. The scales are used in traditional medicine, principally in China and Vietnam, for a range of claimed effects, and they are made of keratin and therefore have no more pharmacological content than fingernail clippings, which is stated plainly by the relevant medical authorities and has not reduced demand. The meat is eaten as a luxury. All eight species are protected under international trade rules, with commercial trade prohibited since 2017, and seizures of many tonnes of scales continue to be made regularly.

The group divides into eight species and the distinction matters for conservation, since the trade has moved between them as populations collapsed. Four live in Asia, across India, southern China and south east Asia, and were the original source of the trade. Four live in Africa, including two tree-dwelling species and two ground-dwelling ones, and shipments of African scales into Asian markets have grown enormously as Asian populations declined, which is a documented shift visible in seizure records. Sizes range from around two kilograms to over thirty. Some climb and have prehensile tails, some dig extensive burrows, and one African species walks upright on its hind legs with the tail counterbalancing.

Conservation faces difficulties beyond the scale of the trade. The animals are nocturnal, solitary and secretive, so counting them is extremely difficult and population estimates are correspondingly poor, which makes it hard to demonstrate decline or recovery. They breed slowly, with one offspring at a time, so populations recover slowly from losses. They survive badly in captivity, since the diet is difficult to replicate and the animals are prone to stress and digestive disease, so captive breeding has succeeded only in a handful of institutions and cannot supply the trade or restock the wild. Rescued animals frequently die. And enforcement must operate across many countries with limited resources.

The scales are keratin, the same material as hair and fingernails, growing continuously and overlapping so that rolling into a ball defeats nearly every predator. The animal has no teeth, a tongue anchored near the pelvis and a stomach containing swallowed grit. Demand for scales in traditional medicine drives the largest trade in any wild mammal, and the material has no pharmacological content at all.