Pangolins have large, protective keratin scales covering their skin; they are the only known mammals with this adaptation. They live in hollow trees or burrows, depending on the species. Pangolins are nocturnal, and their diet consists of mainly ants and termites which they capture using their long, specially adapted tongues. They tend to be solitary animals, meeting only to mate and produce a litter of one to three offspring which are raised for about two years. Pangolins are threatened by hunting (for their meat and armor) and heavy deforestation of their natural habitats, and are the most trafficked mammal in the world. Of the eight species of pangolin, four species (Phataginus tetradactyla, P. tricuspis, Smutsia gigantea, and S. temminckii) are listed as vulnerable, two species (Manis crassicaudata and M. cullonensis) are listed as endangered, and two species (M. pentadactylaand M. javanica) are listed as critically endangered on the IUCN Red List of Threatened Species.
The physical appearance of a pangolin is marked by large, hardened, overlapping plate-like scales. The scales, which are soft on newborn pangolins but harden as the animal matures, are made of keratin, the same material of which human fingernails and tetrapod claws are made. The pangolin's scaled body is comparable to a pine cone or globe artichoke. It can curl up into a ball when threatened, with its overlapping scales acting as armourand its face tucked under its tail. The scales are sharp, providing extra defense. The front claws are so long they are unsuited for walking, so the animal walks with its fore paws curled over to protect them.
Pangolins can also emit a noxious-smelling chemical from glands near the anus, similar to the spray of a skunk. They have short legs, with sharp claws which they use for burrowing into termite and ant mounds, as well as climbing. The size of pangolins varies by species, ranging from 30 to 100 centimetres (12 to 39 in). Females are generally smaller than males. The tongues of pangolins are extremely elongated and extend into the abdominal cavity. Like those of the giant anteater and the tube-lipped nectar bat, they are not attached to their hyoid bone and extend past their pharynx deep into the thorax. This extension lies between the sternum and the trachea. Large pangolins can extend their tongues as much as 40 centimetres (16 in), with a diameter of only 0.5 centimetres (0.20 in).
Most pangolins are nocturnal animals that use their well-developed sense of smell to find insects. The long-tailed pangolin is also active by day, while other species of pangolins spend most of the daytime sleeping, curled up into a ball. Arboreal pangolins live in hollow trees, whereas the ground dwelling species dig tunnels underground, to a depth of 3.5 metres (11 ft). Pangolins are also good swimmers.
Pangolins are insectivorous. Most of their diet consists of various species of ants and termites and may be supplemented by other insects, especially larvae. They are somewhat particular and tend to consume only one or two species of insects, even when many species are available to them. A pangolin will consume an average of 140 to 200 g (4.9 to 7.1 oz) of insects per day.
Pangolins have a very poor sense of vision, and therefore rely heavily on smell and hearing. After locating their prey, they tear open the anthills or termite mounds with their powerful front claws. Their front claws are so large that their front feet are not useful for walking. The animal uses its long tail to counterbalance its torso as it walks on its two hind legs. After tearing open the ant or termite mound, it uses its long tongue to probe inside the insect tunnels and retrieve its prey. They have glands in their chests to lubricate the tongue with sticky, ant-catching saliva. The tongue extends all the way into a cavity of the abdomen and is longer than the pangolin's entire body length. Pangolins lack teeth and, therefore, the ability to chew, however, they ingest small stones while foraging, which accumulate in the muscular stomach and help to grind up ants. Some species, such as the tree pangolin, use their strong, prehensile tails to hang from tree branches and strip away bark from the trunk, exposing insect nests inside.
Pangolins are solitary and meet only to mate. Males are larger than females, weighing up to 50% more. While there is no defined mating season, they typically mate once each year, usually during the summer or autumn months. Rather than the males seeking out the females, males mark their location with urine or feces and the females will find them. If there is competition over a female, the males will use their tails as clubs to fight for the opportunity to mate with her.
Gestation lasts for approximately 120–150 days. African pangolin females usually give birth to a single offspring at a time, but the Asiatic species may give birth from one to three. Weight at birth is 80 to 450 g (2.8 to 15.9 oz) and the average length is 150 millimetres (5.9 in). At the time of birth, the scales are soft and white. After several days, they harden and darken to resemble those of an adult pangolin. During the vulnerable stage, the mother stays with her offspring in the burrow, nursing it, and will wrap her body around it if she senses danger. The young cling to the mother's tail as she moves about, although in burrowing species, they remain in the burrow for the first two to four weeks of life. At one month, they first leave the burrow riding on the mother's back. Weaning takes place at approximately three months of age, at which stage the young begin to eat insects in addition to nursing. At two years of age, the offspring are sexually mature and are abandoned by the mother.
Pangolins are hunted and eaten in many parts of Africa and are one of the more popular types of bush meat. They are also in great demand in Southern China and Vietnam because their meat is considered a delicacy and some believe that pangolin scales have medicinal qualities. This, coupled with deforestation, has led to a large decrease in the numbers of giant pangolins. In November 2010, pangolins were added to the Zoological Society of London's list of genetically distinct and endangered mammals. All eight species of pangolin are classified by the IUCN as threatened to extinction, while two are classified as critically endangered.
Though pangolins are protected by an international ban on their trade, populations have suffered from illegal trafficking due to unfounded beliefs in East Asia that their ground-up scales can stimulate lactation or cure cancer or asthma. In the past decade there have been numerous seizures of illegally trafficked pangolin and pangolin meat in Asia. In one such incident in April 2013, 10,000 kilograms (11 short tons) of pangolin meat was seized from a Chinese vessel that ran aground in the Philippines.
As a result of increasing threats to pangolins, mainly in the form of illegal, international trade in pangolin skin, scales, and meat, these species have received increasing conservation attention in recent years. For example, in 2014, the IUCN (International Union for the Conservation of Nature) re-categorised all eight species of pangolin on its Red List of Threatened Species, and each species is now threatened with extinction. Also, the IUCN SSC Pangolin Specialist Grouplaunched a global action plan to conserve pangolins, dubbed 'Scaling up Pangolin Conservation' in July 2014.