Curious Creatures to Whom the Ant is La Haute Cuisine Redford, Kent H. Smithsonian, August, 1983, ( Vol. 14 ; Pg. 74; ISSN: 0037-7333) Curious creatures to whom the ant is la haute cuisine. One day recently I picked up a few termites and ate them, wondering at their widespread appeal. These particular ones proved to be dry and hard and with a faintly resinous aftertaste; in fact, I have yet to eat ants or termites that tasted good raw. My opinion notwithstanding, these insects are the preferred food of some of the most unusual animals alive today: the myrmecophagous (ant- and termite-eating) mammals. This group includes anteaters, armadillos, pangolins, the aardwolf, echidnas, the numbat and, beloved of crossword-puzzle addicts and amateur poets, the aardvark. With the exception of armadillos and anteaters, these mammals are not closely related, sharing only a common passion for ants and termites. For a long time termites were called "white ants," and so the descriptive name "anteater" was used to refer to both ant- and termite-eating mammals. Most myrmecophagous mammals eat both, although some species appear to restrict themselves to one or the other. Only 22 mammals can be considered true ant and termite eaters: not many out of the 4,170 known species. This is particularly striking when one considers that in some areas ants and termites comprise up to 75 percent of the total animal biomass. In fact, the number of individual ants and termites alive at this moment is greater than the number of all humans who have ever lived. That is a lot of potential food. Where you find a lot of ants or termites you usually find one of these curious predators. Each of the world's tropical areas has its own anteaters. In South and Central America, where I spent two and a half years, anteaters share the myrmecophagous niche with a variety of armadillos. The anteaters range from the giant at 100 pounds or so down to the pygmy at about a pound. Armadillos, which range from Kansas and Missouri to Argentina, are unique in the mammal world in possessing a hardened shell made of bony plates and teeth with no enamel. Africa has the most myrmecophages. The aardvark is a heavy-bodied digging machine with a penchant for turning somersaults before entering its burrow. The aardwolf, on the other hand, is a degenerate termite-eating hyena. Then there are four species of pangolins, which resemble toothless, living pinecones, covered with scales. Another three speices occupy the myrmecophagous niche in Asia. Like aardvarks, pangolins have no living relatives. Australia, an island continent where evolution has marched to the beat of a different drummer, has produced its own versions of anteating mammals. The echidna, or spiny anteater, is related to the platypus, while the second Australian myrmecophage, related to the American opossum, is the marsupial numbat, or banded anteater, a creature of the eucalyptus forests. The practice of eating amts and termtes differs from eating other insects in important ways. The key to the difference lies partially in the existence of different castes of ants and termites specialized for different tasks. There are two sterile castes: workers for gathering food and building the nest, and soliders for defending the colony. As nonreproductive defenders of the colony, soldier ants and termites demonstrate a remarkable range of antipredator behaviors. Termites, to a much grater degree than ants, have a soldier caste highly specialized for colony defense, a caste that has been called one of "nightmarish monsters, which recall the most fantastic revelries of hieronymus Bosch, Bruegel the Elder and Callot." This nightmarish quality arises from the strnage shapes into which soldier-termite heads have been contorted in developing different forms of colony defense. Many of these forms involve chemical secretions. This sort of chemical warfare has reached its apogee in termite soldiers that spray their predators with sticky, repellent and sometimes toxic compounds from a nozzle-shaped head. Monstrous soldiers notwithstanding, termites and ants are eaten by mammals, and eaten in great numbers: an estimated 124,000 termites were found in one South African aardwolf stomach. It is hard to pick up this many swarming insects one by one, as I can attest after spending many weeks trying. Most anteaters would agree; they gave up long ago. Teeth and the precision they allow have been traded for tongues: relatively long, mobile tongues and large salivary glands to keep them moist are trademarks of this group of mammals. A pangolin tongue is so long that one end is attached to the pelvis. These long tongues cna be manipulated very rapidly; I have estimated a giant anteater's to flick in and out faster than twice a second. The tongue can be extended 18 inches and drips with saliva as it sweeps through termite galleries securing hapless insects. Those myrmecophages that still have teeth appear to be losing them. Most of the grinding action of the teeth has been taken over by heavily muscularized portions of the stomach, or, in the case of the echidna, by pseudoteeth located on the tongue. Teeth may also have been lost or become nonfunctional because so much earth is taken in by the sticky tongue as it picks up ants and termites. As much as 47 percent of the contents of aardvark stomachs has been reported as sand, an observation common to all ant and termite eaters. If this abrasive material were ground between chewing teeth, it would rapidly wear down the enamel. Most of the myrmecophagous mammals are diggers; virtually all the terrestrial forms live in holes excavated by themselves or other animals. The giant armadillo, giant pangolin and aardvark are immensely powerful diggers. The burrow system of the aardvark appears to be the most extensive of any of these animals. A gruesome story is told of three Africans who went down an aardvark burrow and disappeared. Their friends started digging for them, but gave up after having excavated a labyrinth 18 feet below ground. The echidna and naked-tailed armadillo, though smaller, are powerful diggers; I have seen a two-pound armadillo completely bury itself in hard ground in less than 30 seconds. These strong diggers all seem to obtain the majority of their ant and termite prey from colonies they excavate, often feeding for long periods of time in the excavated colony. Claws rip open ant hills--and attackers The myrmecophages with the greatest ability to dig are appropriately equipped with strong forelegs and claws capable of moving a lot of dirt. The giant anteater, which has extremely powerful forelegs, is equipped with several long, narrow, sharp claws, one much longer than the rest. Giant anteaters walk on the sides and knuckles of their hands with the claws carried back, thus protecting them from wear. The powerful forelegs and long claws are used for defense as well. Slow-moving anteaters, when threatened, will sit back on their hind feet, balancing with their bushy tails, and strike out with their front feet. Any animal unwary enough to be caught in their grasp will be clutched to the body and torn apart. Reports exist of the disemboweling of dogs, jaguars and even people; I have seen the scars left on the arm of a man who, in a drunken state, had accepted a dare to wrestle with a giant anteater. The claws and powerful forefeet are not just for defense, howver. In my research, I frequently saw anteaters use their claws to rip open ant hills and termite mounds. Unlike giant armadillos, giant anteaters usually did not excavate a colony but rather used their powerful forelimbs and sharp claws to tear narrow deep gashes into the sides of termite mounds. Observations on captive animals showed that all but two of the claws can be held back, which allows the longest one to be used with great precision and with great force immediately adjacent to the nose of the feeding anteater. The quarter-inch-thick aluminum trays on which I served termites were frequently gashed through with one motion of this claw. Most of the other myrmecophagous mammals find their food without digging. They seek out groups of social insects that are away from their nests, scraping away covered termite-foraging areas or turning over termite-infested branches. Any foraging ants and termites found unprotected above ground are eaten. Some pangolins are reported to pick up termite-inhabited cow patties an turn over on their backs before commencing to feed. Holding the cow patty in its claws, the pangolin breaks it open and consumes the termites as they fall onto its belly. Myrmecophages, like herbivores, tend to graze, feeding for only a short time in each place. Almost half of the times I saw giant anteaters feeding, they fed for less than ten seconds. Several factors seem to affect a myrmecophage's decision to leave a given feeding spot. First, there may be nothing left on which to feed, since the defense of many ant and termite species is simply to flee. Second, the available food may all have been eaten, as in the case of small foraging parties of termites. Third, and most interesting, are the occasions on which ants and termites are still abundant when the anteater stops feeding and leaves. Some researchers have suggested that this may be an adaptation on the part of the predator, a way of harvesting instead of destroying social-inscet colonies; they consider it a form of what has been called "prudent predation." Others have shown, however, that the short feeding bouts that characterize many myrmecophages are probably not the result of a prudent decision made by the predator, but are forced on it by its prey. Not all ants and termites take predation lying down. From my observations on giant anteaters and the observation of others on tamandua anteaters and aardwolves, it appears that those insects that fight back, especially termites, exhibit a coordinated defense connected with the use of a form of chemical repellent. Worker termites are defenseless and are usually preferred by anteaters over the soldiers that protect them. So when the anteater starts feeding on workers, the few soldiers present discharge their load of chemicals, attracting other soldiers. The reinforcements swarm to the site of the attack and in turn discharge their chemicals. In a very short while the concentration of chemicals, different ones smelling to us like blue cheese, lemon-scented furniture polish or pine woods, is sufficiently high to drive the anteater away, leaving a spot covered with very upset soldiers. Termite soldiers using chemical defenses appear to be effective in limiting, if not preventing, predation by many kinds of mammals. Ants and termites can reach staggering abundance in some areas, and so it is not surprising that even with their array of defensive strategies they are a major food source. Many mammals that do not depend on ants and termites to survive still eat them frequently. Such species can be termed "amateur myrmecophages." Among the amateurs are the sloth bear, the bateared fox (above), some mongooses and some mice, which are more semipro than amateur. Termites and ants comprise about half of the total diet of sloth bears and bat-eared foxes, while half of the black-legged mongoose's diet seems to be composed of the unlikely food of driver ants--the Old World's army ants. Most of the rest of the amateur ant and termite eaters, however, probably eat significant numbers of social insects only because they are there. These animals, including some jackals, some armadillos, some monkeys, some squirrels and some elephant shrews, feed in a manner and in a location which causes them to enconter many ants and termites. And, not being overly fussy, they eat what is available. At one point of their life cycle, ants and termites become irresistible to an even broader range of animals. Usually following the first rains, ant and termite colonies pour forth alates, winged males and females which mostly end up as food. These alates appear by the hundreds of thousands and flutter weakly about seking mates and appropriate places to found new colonies. Alates are very appetizing because they have a lot of stored fat and less chitinous armor. They make particularly easy prey because they themselves are virtually defenseless and are away from whatever protection their soldier caste might have provided. Many mammals feed on these alates, and it is quite likely that the energetically expensive business of reproduction in some mammals is tied to the appearance of these winged reproductives. Such a correlation has already been suggested for birds. Foxes and hyenas have been seen standing outside termite exit holes, snapping up alates just as they emerge on their perilous journey. Some african monkeys, who have apparently learned that alates of a certain species of termite congregate near the tops of trees, climb these trees and grab the flying reproductives out of the air. Chimpanzees can also be found swaying in the tree-tops during swarms, but search out and eat many kinds of ants and termites. They fish for termites by sticking twigs or blades of grass down holes in a termite mound. The tool is then withdrawn, with up to a dozen termite soldiers biting into it. These are bitten directly off, like toasted marshmallows, or picked off with the fingers. Five chimpanzees sitting around a driver ant nest with their tools create a scene reminiscent of guests, forks in hand, around a fondue pot. Chimpanzees are not the only myrmecophagous higher primates, for humans consume large quantities of both ants and termites. Human beings are particularly fond of alate ants and termites; especially in Africa they will go to great lengths to secure them. All sorts of devices and stratagems have been designed to collect alates; one is to water the termite mound before the first rains, thereby tricking the alates into leaving the mound prematurely. Humans have also developed the technique of "fishing" for termites. One person can collect a basketful of soldiers which, dried, can be seen for sale in some African markets. One wonders who learned how to fish from whom. The female alates of the big South American leafcutting ants are also a delicacy; in some areas they may even be a seasonally significant source of nutrition. In 1953, A. R. Wallace commented on his disquietude at observing that in one Indian tribe of the Amazon, breakfast began by opening a stoppered calabash and allowing a few live ant alates collected the day before to crawl out. The alates were then consumed raw with handfuls of manioc flour. Humans are not built to be myrmecophages, of course; we do not have long snouts or 18-inch tongues. But then neither do mice, mongooses, bat-eared foxes or sloth bears. The individual shown opposite, which happily eats ants when it finds them, could never be mistaken for an anteater. Yet where culture encourages it, ants and termites are an important source of protein in the human diet. In the end, it all comes down to a question of taste. Henry Smeathman, in 1781, expressed surprise that the European palate would enjoy the taste of the alates of African Macrotermes, saying, "I have discourced with several gentlemen upon the taste of the white ants termites ; and on comparing notes we have always agreed that they are most delicious and delicate eating. One gentleman compared them to sugared marrow, another to sugared cream, and a paste of sweet almonds." While I have never tasted sugared marrow, I can add my comment that, unlike raw workers or soldiers, fried, salted alates are probably the best cocktail snacks I have ever tried. But then I'm not a true myrmecophage.