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Tamanduas:  A Vested Interest in Ants

by Joe E. Meisel
© 2003 Ceiba Foundation for Tropical Conservation

Tamandua mexicana on a vine in Costa Rica

You wouldn't think that a diet of only ants and termites could keep large animals happy, but the tropical anteaters called tamanduas have figured out a successful strategy. Much like large bears can feed themselves by regularly visiting known berry patches, tamanduas return to the same ant and termite nests again and again to feed from the larvae found deep within. To the tamanduas, these small insects are a reliable food source which, although they seem small and non-nutritious to you and me, can support these handsome anteaters thanks to their many special adaptations.

Tamanduas are mammals of the ancient order Xenarthra, which includes animals with very simple teeth or, as in the case of the tamanduas, no teeth at all. Instead the tamanduas all have strong, muscular stomachs capable of grinding the ants they eat, instead of chewing them. Tamanduas show remarkable skill at capturing ants, thanks to their powerful front legs and sturdy claws that allow them to tear into ant nests and termite mounds, into which they jam their long snout and put to work their famous tongues. All anteaters have extremely long tongues, some up to 60 centimeters long! Equipped with backwards pointing hairs, and coated with gooey saliva, the tongue is used to scoop up ants and termites from inside the nest, and especially their larvae. The tongue is then pulled back into the snout covered with ants which are then swallowed, not unlike a small child who will lick a finger and poke it into a bag of sugar so the sweet crystals stick to the wet fingertip.

Since many ants and termites in the tropics live high in the trees, most tamanduas are adapted to an arboreal lifestyle, although they will spend considerable time on the ground if ants and termites are more abundant there. Arboreal tamanduas are equipped with a strong prehensile tail that grabs vines and branches while they climb and helps hold them in place as they use their front legs to tear open the nests of their prey. Because of their heavy claws, anteaters have had to devise a different way of walking when on the ground, where they lope along using specialized pads on the sides of the paws. Although they are normally slow moving, conserving their energy as they forage, they can run at surprising speeds when frightened. In the trees, their prehensile tail and the special shape of their paws (which has a central fold permitting them to grasp narrow vines) allows them to move easily and noiselessly through the forest canopy.

Anteaters have very good spatial memory, too, carrying in their head a map of all the ant and termite nests in their home range, and keeping track of how recently each one was visited. Like the bear eating berries from many different bushes, they allow their prey ample time to recover before they return to raid the nest again. When feeding at a nest, they usually will quit after only a few moments, just when the colony mobilizes soldiers to defend the breach. They distinguish between ant and termite species, preferring large colonies that are less aggressive, and avoiding species with fearsome stings. Finally, anteaters have a very low metabolism compared to other mammals of their size, an adaptation thought to help them survive on a nearly pure diet of ants and termites, which provide a regular but not rich source of calories.

Anteaters spend a lot of time teaching their young how to live off this specialized diet. Female tamanduas only give birth to a single offspring, which accompanies the mother for many months, riding on her back and clinging tightly to her fur. The youngster gradually learns the techniques for finding nests, tearing them open, sucking the ants and larvae from inside, withdrawing once defensive soldiers appear, and maintaining a map of feeding sites that it has visited. Because of this lengthy period of maternal care, tamanduas do not have high rates of reproduction, and are ill-suited to withstand the pressures of hunting and deforestation.

Neotropical (meaning from the New World, or American, tropics) anteaters developed in South American when it was still an enormous island, isolated from the rest of the world. Ants were already highly abundant there, and became the tamanduas' primary food source. Today, there are four surviving species of anteater that range from 300 grams to 30 kilos. Although they can be quite abundant in good habitat, they are infrequently seen by visitors to the tropics. Shy, they often flee at the sound of humans, or they may hide quietly on a tree branch high over your head. However, signs of their presence are common. By day, look for ant and termite nests with rough, large holes excavated in the sides (much smaller, round holes are often made by nesting birds), or you can look for chunks of these nests that have fallen to the ground during the assauly. By night, listen carefully for the sound of dirt raining out of the treetops and striking the forest floor. This characteristic clue of a tamandua at work ripping into an ant nest is one of the most reliable methods scientists use to find anteaters in order to study them.

Silky AnteaterOf the four anteaters, the smallest is the attractive Silky Tamandua (Cyclopes didactylus) weighing around 200 grams. With long, golden fur that is soft and slightly wavy, their name is very fitting. In fact, several of the local names for this gorgeous creature even translate as "little angel." Silky tamanduas are totally arboreal and nocturnal, and thus can be difficult to see when active; however, they are occasionally spotted sleeping by day, when they curl up into a tight golden furball usually in a tangle of vines. Sometimes, silky anteaters will rest in Ceiba trees, whose fluffy seed pods provide excellent camouflage for these small golden creatures. Since their principal predators are large hawks and eagles, passing the daylight hours as just one golden furry ball among many is excellent protection!

Northern TamanduaThe most typical tropical anteaters are divided into two species, the Northern and Southern Tamanduas (Tamandua mexicana and tetradactyla) each weighing roughly 5 kilos. The northern tamandua is found from Mexico to northern Ecuador, while the second species replaces it in the rest of South America. The northern tamandua is an endearing animal that looks as if it is wearing a dignified black vest, contrasting sharply with the light tan fur covering the rest of its body. There is a good deal of variation in the tamandua's coat, however, and many animals of the southern species are a pure golden color with no vest at all. In Central America, tamanduas are not uncommonly seen ambling through the forest floor, and occasionally will run up a tree when spooked, only to come to rest a few meters off the ground and hold very still, a great response if you are a photographer! Unfortunately, southern tamanduas are listed as endangered by CITES (Convention on International Trade in Endangered Species), since some local hunters suffer from the superstition that they habitually kill dogs, and because the extremely resilient tendons in their prehensile tails are used to make strong rope.

Giant AnteaterLargest of the four species is the Giant Anteater (Myrmecophaga tridactyla), whose name literally means "eater of ants". Found in South American, these anteaters spend all their time foraging on the ground, although they are capable of tree climbing, and can weigh up to 30 kilos. Giant anteaters live in a wide variety of habitats, and although they are found in primary rainforest, they are far more easily seen by visitors in open areas with low vegetation. They are known to have very poor eyesight and hearing, and instead rely on their keen sense of smell to find the large termite mounds and ant nests on which they feed. Giant anteaters are listed by CITES as threatened, due mainly to habitat loss, and some hunting. Their principal wild predators are South America’s big cats, the jaguar and puma. Because of their powerful forelimbs, they can defend themselves fiercely, rearing up on their hind legs and slashing with their heavy claws.

Tamandua on highway in EcuadorIt is an unfortunate fact that most of the visitors to the tropics that actually see a tamandua will probably see a dead one, crushed by an automobile while attempting to cross a busy country road. As mentioned, tamanduas cover a considerable area in search of their ant and termite prey, often traveling more than a kilometer per day as they cruise within large (25 hectare) home ranges to harvest their dispersed food source. As tropical habitats become increasingly fragmented by roads, it is an unavoidable consequence that the movements of these graceful creatures will cause them to come into contact, sometimes all too literally, with civilization. If one surveys the largest wild animals most commonly killed on roadways, tamanduas and sloths rank at the very top. In addition to road deaths, tamanduas are threatened by the common tropical threats of deforestation, hunting and habitat degradation. For example, extraction of standing dead trees in a small forest reserve can significantly reduce the number of termite colonies in the reserve, depriving the tamanduas of their precious food resource.

Solutions to these problems do exist, however, and there is good cause for optimism in the case of tamandua conservation. First and foremost, tamanduas are not dangerous creatures nor are they particularly tasty to eat. Therefore, reducing hunting pressure on them should be much easier than on large cats, for example, which inspire fear in people and are thought of (usually mistakenly) as threats to cattle, pets or children. Second, tamanduas feed on animals that are often thought of as pests to humans, the termites that destroy our wooden buildings, and the ants that ruin our picnics and infest our kitchens. While ants and termites clearly have many important roles to play in the tropics, it should be possible to focus environmental education efforts on the role of tamanduas in controlling the populations of these insects.

There is another creative conservation idea that may come to the rescue of tamanduas and other mobile, arboreal animals (such as sloths, monkeys, iguanas, and a whole host of smaller mammals). Since these animals spend much or all of their lives in the trees, following paths through the forest on branches and thick vines, it is natural to assume that they will search for arboreal paths first when attempting to cross roads. Normally, trees are cut away from roadsides so that branches do not fall into traffic. However, it is entirely possible to construct arboreal bridges, let's call them "climbways," that pass over roads at locations where tamanduas are routinely found attempting to cross roads on the ground. These locations might be caused by the pattern of forest on the landscape, such as where two large forests meet at a pinched-in area, like an hourglass, or they might be determined by the biology of the tamanduas, which may use certain parts of the forest more intensively for travel, and hence encounter roads at predictable points. In either case, a simple survey of roads for dead tamanduas should, over time, provide an indication of where they are most commonly attempting crossings.

Once those locations are determined, it is a simple matter to install several climbways and monitor them for use by tamanduas and other arboreal animals. Wooden poles are sunk on both sides of the road, and one of several types of swinging bridges are connected to the poles: the bridges can range from simple, narrow ropes or cables to broader structures that permit larger animals to cross. Cameras can be installed, triggered by infra-red sensors, that would send back or store images of all the animals that used the climbway. Such a solution has already been employed in Belize, where several such bridges have been constructed to allow howler monkeys to travel between different forest fragments.

It is a truly heartbreaking sight to find such an innocuous and beautiful animal as a tamandua lifeless on one of our roads, thanks to accidental collisions with automobiles whose drivers had no malicious intent in their hearts -- perhaps they were merely going home from work, or driving their children to school. In part, these incidents are an inevitable result of the collision between the forested world and the world of motorized civilization, when arboreal mammals are forced to descend from the safety of their trees to attempt to cross busy roads. However, the danger that roads present to tree-climbing animals is not wholly inescapable. If humans can design train crossings to protect motorists, and pedestrian crossings to protect people, then surely we can design climbways to protect the animals of the forest canopy. I'm sure that tamanduas, and generations of visitors to tropical forests hoping to see them, will appreciate our efforts.



Do you want to help? Please contact Ceiba about our arboreal mammal conservation fund, and make a donation to help get this project off the drawing board and into the field.

 






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