Pangolins, also known as scaly anteaters, are unique mammals recognized by their distinctive armor of scales. As the most trafficked mammal in the world, understanding their dietary needs is crucial for conservation efforts, especially in ex situ breeding programs. This article explores the natural diet of pangolins, their feeding habits, and the challenges of replicating their diet in captivity.
What are Pangolins?
Pangolins are part of the order Pholidota, an ancient group of mammals that has been around for approximately 80 million years. Despite their reptilian appearance, pangolins are mammals, representing one of the most ancient mammalian orders - Pholidota, going back nearly 64 million years in the fossil record. There are eight extant species of pangolins, four native to Asia and four to Africa.
Asian Pangolin Species:
- Chinese Pangolin (Manis pentadactyla): Native to the northern Indian subcontinent, northern parts of Southeast Asia, and southern China. Unlike African species, which prefer lowlands, Chinese pangolins have been recorded at elevations up to 3,000 metres.
- Indian Pangolin (Manis crassicaudata): Found across India and Sri Lanka, inhabiting grassland, forest, and dry, desert areas, and have even been found in Sri Lankan rainforest. They have been recorded at an elevation of 2,300m in India’s Nilgiri mountains.
- Sunda Pangolin (Manis javanica): Found in the forests of southeast Asia, including Thailand, Cambodia, Malaysia, Singapore, and Vietnam, but also specifically the islands of Borneo, Java, Sumatra, and the Lesser Sunda Islands. The Sunda pangolin has a longer head than other Asian pangolins and their claws are a similar length in both front and back legs.
- Philippine Pangolin (Manis culionensis): Endemic to the Palawan province of the Philippines. The Philippine pangolin has a short head length and the most rows of scales of all of the pangolin species. They have the smallest scales of all of the Asian pangolins and their claws are a similar length in both front and back legs.
African Pangolin Species:
- Tree Pangolin (Phataginus tricuspis): Native to equatorial Africa and strictly arboreal. Also known as the white-bellied pangolin (also known as the tree pangolin or three-cusped pangolin) is the most common of the African forest pangolins. They are found through much of central and western Africa, and as far east as southwestern Kenya and northeastern Tanzania.
- Long-tailed Pangolin (Phataginus tetradactyla): Found in Central and West Africa and also arboreal. The black-bellied pangolin is the only species of pangolin to have black skin.
- Giant Pangolin (Smutsia gigantea): The largest and rarest of the species, having now gone extinct in various parts of Africa. The giant pangolin has its largest populations in Uganda, Tanzania, and western Kenya, but is thinly distributed across the western coast of Africa too.
- Cape Pangolin (Smutsia temminckii): Found all over South Africa. The Temminck’s, or ground pangolin, is one of the most widespread of the African species and is the only one found in southern and eastern Africa. They prefer scrubby, savannah woodland at low elevation. Like most pangolin species, they live in burrows - which have semispherical chambers and can sometimes be large enough for a person to stand up in.
Pangolins range in size from 12 inches (30 cm) to 4.5 feet long (1.3 meters). They are covered in overlapping scales made of keratin, the same protein that makes up human hair and nails. These scales account for 20% of its body weight. Their tongues are exceptionally long, sometimes longer than their bodies, and are specifically designed for capturing their favorite food. Pangolins are nocturnal and solitary, mating only once a year. They typically produce one offspring a year, called pangopups. Pangopups cling to their mothers' tails when they are too small to travel alone.
The Natural Diet of Pangolins: Insectivores of the Wild
Almost all pangolin species are strictly myrmecophagous, meaning they primarily feed on termites and ants. These specialized insectivores use their sharp claws to tear apart insect nests and their long, sticky tongues to capture burrowing insects. In fact, pangolins consume up to 20,000 insects per night. The pangolin’s unwavering appetite for termites and ants, as well as other insects and larvae, assists with the regulation of insect populations within several Asian countries. Pangolins are believed to consume approximately 70 million insects per annum, equating to almost 200,000 insects per day.
Field studies have shown that in addition to ants and termites, a pangolin’s diet includes insect larvae, bees (pupae), flies, earthworms, crickets, and some other arthropods, sometimes also sand, small grains, and grass during feeding. Pangolins have small heads, long snouts, and brawny front claws, which they use to excavate mounds, stumps, and fallen branches with ease. Due to a lack of teeth, pangolins have spectacularly long, powerful, sticky tongues used for lapping up insects within deep cavities. These gluey appendages can reach up to half the length of the pangolin’s body. Since pangolins cannot chew their food, these incredible creatures have developed a specialised stomach that aids with their digestion. The pangolin’s stomach is lined with keratinous spines which, when paired with a few stones purposefully swallowed by the animal, crushes and grinds their prey in a similar fashion to a bird’s gizzard.
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Notably, pangolins may not have a particular preference for ant species. Studies have found that pangolins feed on various ants and termites without an obvious preference. However, some ants were unacceptable to pangolins, leading researchers to speculate that the nutritional composition, palatability, and safety of food are important factors in pangolin food selection. In Tswalu Kalahari Reserve, researchers analyzed pangolin scats to learn about their diet. They found that pangolins consumed between 1,000 and 60,000 insects per night (about 15,000 insects, on average). The pangolins were incredibly fussy eaters, focusing their diet on only three ant and termite species found at Tswalu. Despite shifting their diet when resources were scarce, pangolins were unable to maintain the same high energy intake during winter as they did in summer.
Nutritional Composition of Wild Pangolin Diet
The nutrient profile of different species of termites and ants and even the same species of termites and ants but different types (queens, soldiers, etc.) also displays differences. The crude protein content of some ants is higher than that of other foods, such as eggs, milk, and common cat food. The mineral and vitamin concentrations of ants also exceed many common food items, such as oil, meat, and eggs. However, not much is known about the bioavailability of minerals from ants and termites.
In general, the natural diet of pangolins is high in crude protein, with varying levels of fat, minor amounts of carbohydrates, and varying levels of ash (hence minerals). The ratio of non-protein energy to protein energy (NPE/PE) of ants ranges between 0.48:1 and 1.2:1.
Nutritional Needs and Ex Situ Feeding
For most pangolins that move from the wild to captivity, it is important to provide a diet that allows a smooth adaptation to the new environment. However, due to the special feeding traits of pangolins and their high dependence on a natural ecosystem, many technical obstacles still limit the success of captive pangolin breeding. The transition of pangolins from wild ants to a “gruel” diet under human care is difficult, and the pangolin’s nutritional needs are less well studied, which is why providing adequate nutrition is the biggest barrier to ex situ breeding. The diet under human care contains fewer insects, with. Studies have suggested that pangolin health is related to nutrition and parasite infection. For example, some pangolins suffer from gastrointestinal diseases and die of malnutrition because the artificial food provided is not suitable for their digestive system. There have also been intestinal parasites and nutritional failures caused by prolonged starvation. Even pangolins that are able to eat artificial food on their own also die of gastric perforation disease due to food inadaptability. Therefore, it has been postulated that malnutrition is the main reason pangolins cannot thrive under human care.
Challenges in Replicating Natural Diet
The requirement of ant breeding is strict on temperature and humidity, and the breeding time is from March to October, so the availability of ants is reduced at other times. For larger-scale care of pangolins, there are not enough natural ant resources to meet their nutritional needs, which implies insufficient food supply for pangolins under human care and will affect the display of natural behavior.
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The type of food used in successful pangolin protection agencies is quite variable in nutritional composition. Due to differences in geographical environment and biological abundance, the types of food and nutritional composition in different pangolin protection agencies show great differences. Diets range in their levels of invertebrates (ants, red weaver ants, green weaver ants, weaver ant eggs, red ants, bee larvae, silk worms, and/or mealworms), vertebrates (beef meat, eggs, and/or egg yolks), plant matter (coconut husk, apples, corn flour, and/or soya beans), concentrates (cat kibbles, hedgehog pellets, and/or insectivore pellets), dairy (yoghurt), and supplements (clay, chitin powder, calcium lactate, vitamin B, vitamin A, vitamin K, choline chloride, and/or olive oil) and water.
Artificial Diets for Pangolins
Based on the natural food ingredients of pangolins in the wild, many recipes have been developed for pangolin husbandry, including eggs, meat (ground beef, horse meat, fish), milk, milk powder, orchid leaves, carrots, yeast, multivitamins, and insects. Taipei Zoo has been very successful in raising and breeding pangolins, which is largely related to the gradual development of a suitable diet. Their pangolin diet formula was developed from 1989 to 1995; the researchers optimized a diet for pangolins, consisting of 100 g of mixed silkworm powder (silkworm powder, yeast powder, coconut powder, ratio of 10:2:1), 100 g of bee larvae, 50 g of mealworms, 1 egg yolk, a quarter of an apple, and 0.5 mL infant multivitamin solution.
Other successful artificial diets include:
- Milk, porridge, Crematogaster rogenhoferi Mayr, Polyrhachis lamellidens Smith, locust leaf powder, a multivitamin mixture, glucose, and egg yolk.
- 45% fresh milk, 45% ant powder, and 10% minerals and vitamin supplements.
- Corn flour, mealworm (Tenebrio molitor), soybean powder, fish meal, ant powder, and some food additives (multiple vitamin tablets, salt, glucose).
Comparing Wild and Captive Diets
Based on comparisons between foods, it is clear that the main difference between diets in the wild and in human care of pangolins is that the latter contains fewer insects and vitamins, such as vitamin E, vitamin A, and vitamin B2, and more carbohydrates and non-protein substances than the former. Although many successful dietary formulae have been developed, the pangolin’s nutritional needs are still less well studied. A diet with the nutrient concentrations observed in the wild may add to successful ex situ conservation.
The Role of Pangolins in the Ecosystem
Pangolins are a keystone species, playing a vital role in controlling ant and termite populations, preventing them from overwhelming forest ecosystems. The burrows they dig also benefit the ecosystem, aerating the soil and turning over organic material, and provide an important habitat for other organisms. Pangolins help turn over soil, assisting in soil health.
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Threats to Pangolins and Conservation Efforts
Pangolins face threats on a multitude of fronts - but human demand for their parts and meat is the primary reason most pangolin species are classed as critically endangered. Pangolin scales are used in traditional Asian medicine, with other aspects, such as their blood, being used for tonics. Demand is highest in Asia, and it is the Asian species that have therefore been hit hardest. Pangolins are also losing habitat due to human encroachment, with forestry being turned into agricultural tracts.
It’s estimated that over 1 million pangolins were trafficked between 2010 and 2020, making them the most illegally traded mammal globally. In one 2019 bust in Singapore, some 12 tonnes of pangolin scales were seized, representing 36,000 dead pangolins. Just this year, the Nigeria Customs Service (NCS) successfully seized over 9.4 tonnes of stockpiled pangolin scales.
Conservation Strategies
Due to the unrelenting demand for pangolin scales, all eight species of the scaly anteater have been given the highest level of protection under the Convention on International Trade in Endangered Species (or CITES). However, putting pangolin protection into practice is another story, as only 17 pangolin-range states have enacted legislation that meets CITES requirements; 31 states have not.
Ongoing education and the global rejection of pangolin products for clothes and medicine will have the biggest impact on the pangolin population. Organizations like the IUCN Pangolin Specialist Group and Wildlife Conservation Society (WCS) are other global organizations working tirelessly to protect pangolins through habitat preservation, anti-poaching patrols, and rehabilitation of rescued pangolins.