Pangolin Cc
Maria Mauri
Pangolins have large, protective keratin scales, similar in material to fingernails and toenails, covering their skin; they are the only known mammals with this feature. 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 tongues. They tend to be solitary animals, meeting only to mate and produce a litter of one to three offspring, which they raise for about two years. Pangolins superficially resemble armadillos, though the two are not closely related; they have merely undergone convergent evolution.
Pangolins are threatened by poaching (for their meat and scales, which are used in traditional medicine[16][17]) and heavy deforestation of their natural habitats, and are the most trafficked mammals in the world.[18] As of January 2020[update], there are eight species of pangolin whose conservation status is listed in the threatened tier. Three (Manis culionensis, M. pentadactyla and M. javanica) are critically endangered, three (Phataginus tricuspis, Manis crassicaudata and Smutsia gigantea) are endangered and two (Phataginus tetradactyla and Smutsia temminckii) are vulnerable on the Red List of Threatened Species of the International Union for Conservation of Nature.[19]
The physical appearance of a pangolin is marked by large, hardened, overlapping, plate-like scales, which are soft on newborn pangolins, but harden as the animal matures.[26] They are made of keratin, the same material from which human fingernails and tetrapod claws are made, and are structurally and compositionally very different from the scales of reptiles.[27] The pangolin's scaled body is comparable in appearance to a pine cone. It can curl up into a ball when threatened, with its overlapping scales acting as armor, while it protects its face by tucking it under its tail. The scales are sharp, providing extra defense from predators.[28]
Pangolins can emit a noxious-smelling chemical from glands near the anus, similar to the spray of a skunk.[29] They have short legs, with sharp claws which they use for burrowing into ant and termite mounds and for climbing.[30]
Most pangolins are nocturnal animals[33] which 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 ("volvation").[32]
Some pangolins walk with their front claws bent under the foot pad, although they use the entire foot pad on their rear limbs. Furthermore, some exhibit a bipedal stance for some behaviour, and may walk a few steps bipedally.[34] Pangolins are also good swimmers.[32]
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 can consume 140 to 200 g (5 to 7 oz) of insects per day.[35] Pangolins are an important regulator of termite populations in their natural habitats.[36]
Pangolins have very poor vision. They also lack teeth. They rely heavily on smell and hearing, and they have other physical characteristics to help them eat ants and termites. Their skeletal structure is sturdy and they have strong front legs that are used for tearing into termite mounds.[37] They use their powerful front claws to dig into trees, soil, and vegetation to find prey,[38] then proceed to use their long tongues to probe inside the insect tunnels and to retrieve their prey.
The structure of their tongue and stomach is key to aiding pangolins in obtaining and digesting insects. Their saliva is sticky,[37] causing ants and termites to stick to their long tongues when they are hunting through insect tunnels. Without teeth, pangolins also lack the ability to chew;[39] but while foraging, they ingest small stones (gastroliths), which accumulate in their stomachs to help to grind up ants.[40] This part of their stomach is called the gizzard, and it is also covered in keratinous spines.[41] These spines further aid in the grinding up and digestion of the pangolin's prey.
Pangolins are solitary and meet only to mate, with mating typically taking place at night after the male and female pangolin meet near a watering hole. Males are larger than females, weighing up to 40% more. While the mating season is not defined, they typically mate once each year, usually during the summer or autumn. Rather than the males seeking out the females, males mark their location with urine or feces and the females find them. If competition over a female occurs, the males use their tails as clubs to fight for the opportunity to mate with her.[44]
The order Pholidota was considered to be the sister taxon to Xenarthra (neotropical anteaters, sloths, and armadillos), but recent genetic evidence indicates their closest living relatives are the carnivorans, with which they form a clade, the Ferae.[47][48][49][50] Palaeanodonts are even closer relatives to pangolins, being classified with pangolins in the clade Pholidotamorpha.[51] The split between carnivorans and pangolins is estimated to have occurred 79.47 Ma (million years) ago.[52]
Asian and African pangolins are thought to have diverged about 41.37 Ma ago.[52] Moreover, the basal position of Manis within Pholidota[50][54] suggests the group originated in Eurasia, consistent with their laurasiatherian phylogeny.[50]
Pangolins are in high demand in southern China and Vietnam because their scales are believed to have medicinal properties in traditional Chinese and Vietnamese medicine.[56] Their meat is also considered a delicacy.[57][58][59][60][61] 100,000 are estimated to be trafficked a year to China and Vietnam,[62] amounting to over one million over the past decade.[63][64] This makes them the most trafficked animal in the world.[63][65] This, coupled with deforestation, has led to a large decrease in the numbers of pangolins. Some species, such as Manis pentadactyla have become commercially extinct in certain ranges as a result of overhunting.[66] In November 2010, pangolins were added to the Zoological Society of London's list of evolutionarily distinct and endangered mammals.[67] All eight species of pangolin are assessed as threatened by the IUCN, while three are classified as critically endangered.[19] All pangolin species are currently listed under Appendix I of CITES which prohibits international trade, except when the product is intended for non-commercial purposes and a permit has been granted.[68]
China had been the main destination country for pangolins until 2018, where it was surpassed by Vietnam. In 2019, Vietnam was reported to have seized the largest volumes of pangolin scales, surpassing Nigeria that year.[69]
Though pangolins are protected by an international ban on their trade, populations have suffered from illegal trafficking due to beliefs in East Asia that their ground-up scales can stimulate lactation or cure cancer or asthma.[71] In the past decade, numerous seizures of illegally trafficked pangolin and pangolin meat have taken place in Asia.[72][73][74][75] In one such incident in April 2013, 10,000 kg (22,000 pounds) of pangolin meat were seized from a Chinese vessel that ran aground in the Philippines.[76][77] In another case in August 2016, an Indonesian man was arrested after police raided his home and found over 650 pangolins in freezers on his property.[78] The same threat is reported in Nigeria, where the animal is on the verge of extinction due to overexploitation.[79] The overexploitation comes from hunting pangolins for game meat and the reduction of their forest habitats due to deforestation caused by timber harvesting.[80] The pangolin are hunted as game meat for both medicinal purposes and food consumption.[80]
The nucleic acid sequence of a specific receptor-binding domain of the spike protein belonging to coronaviruses taken from pangolins was found to be a 99% match with SARS coronavirus 2 (SARS-CoV-2), the virus which causes COVID-19 and is responsible for the COVID-19 pandemic.[81][82] Researchers in Guangzhou, China, hypothesized that SARS-CoV-2 had originated in bats, and prior to infecting humans, was circulating among pangolins. The illicit Chinese trade of pangolins for use in traditional Chinese medicine was suggested as a vector for human transmission.[81][83] However, whole-genome comparison found that the pangolin and human coronaviruses share only up to 92% of their RNA.[84][85] Ecologists worried that the early speculation about pangolins being the source may have led to mass slaughters, endangering them further, which was similar to what happened to Asian palm civets during the SARS outbreak.[84][86] It was later proved that the testing which suggested that pangolins were a potential host for the virus was flawed, when genetic analysis showed that the spike protein and its binding to receptors in pangolins had minimal effect from the virus, and therefore were not likely mechanisms for COVID-19 infections in humans.[87]
In 2020, two novel RNA viruses distantly related to pestiviruses and coltiviruses have been detected in the genomes of dead Manis javanica and Manis pentadactyla.[88] To refer to both sampling site and hosts, they were named Dongyang pangolin virus (DYPV) and Lishui pangolin virus (LSPV). The DYPV pestivirus was also identified in Amblyomma javanense nymph ticks from a diseased pangolin.[88]
Pangolin scales and flesh are used as ingredients for various traditional Chinese medicine preparations.[89] While no scientific evidence exists for the efficacy of those practices, and they have no logical mechanism of action,[90][91][92] their popularity still drives the black market for animal body parts, despite concerns about toxicity, transmission of diseases from animals to humans, and species extermination.[89][93] The ongoing demand for parts as ingredients continues to fuel pangolin poaching, hunting and trading.[94]
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