If you were invited to a potluck dinner hosted by a group of aardvarks, anteaters and armadillos, you could just walk outside, find your nearest anthill and scoop a pile of it into a serving dish. Although preventing the ants from crawling all over the dinner table might be a challenge, your culinary contribution would be readily appreciated. That's because these animals are part of a group of mammals that have a particular palate for ants, as the anteater's name implies. In fact, there are only 22 species of animals described as myrmecophagous, or termite- and ant-eating [source: Redford].
Out of that group of 22, anteaters and aardvarks are often lumped together as assumed relatives. People may even refer to aardvarks as "anteaters." Granted, they share similar facial features like elongated snouts and tongues. The anteater's tongue can extend up to 24 inches (60 centimeters) to probe inside anthills and extract ants by the hundreds. Anteaters can flick their tongues in and out of the hill as fast as 150 times per minute [source: Cohn]. At that rate, they may consume 30,000 ants and termites in one day [source: San Diego Zoo].
The aardvark's tongue is about half as long since its body is generally smaller than an anteater's, but it still gets the job done. Both animals' hollow snouts produce a suctioning effect to help suck angry termites and ants quickly out of the mounds and into their mouths. Enlarged salivary glands produce thick, sticky saliva that traps the insects on the tongues.
Anteaters and aardvarks also share sensory similarities. It doesn't take keen eyesight to spot immobile food targets like anthills and termite mounds. Accordingly, both species have lackluster vision but powerful olfactory senses, which allow them to sniff out their subterranean meals. Once they locate their food source, aardvarks and anteaters can use their strong front claws to rip into the mound and start lapping up the tasty ants or termites. By striking deeply and quickly into the insect fortresses, anteaters' and aardvarks' sneak attacks help them avoid the wrath of soldier ants that deliver stinging bites.
But just because two people enjoy eating the same foods with the same utensils doesn't mean they're cut from the same genetic cloth. Rather, they use comparable mechanisms to feed themselves. The same goes with the anteater and aardvark.
Anteaters and Aardvarks: A Nose for Insect Extermination
As unrelated species that have developed parallel traits in isolation from each other, these two animals provide an interesting representation of the phenomenon of convergent evolution. United by their myrmecophagy -- or ant and termite diet -- anteaters and aardvarks are nevertheless separated by an ocean. Aardvarks are native to Africa, named for an Afrikaans word meaning "earth pig." They prefer the floodplains in the southern region of the continent, where they can find water and soft soil for digging. Anteaters are native to Central and South America, where ants abound in the warmer climate.
The two species are also separated by a number of branches in the animal kingdom's genetic tree. Anteaters are part of the order Pilosa, along with sloths. Four anteater species exist, ranging in size from the diminutive silky anteater with a body length less than a foot long to the giant anteater that grows to be about 4 feet (1.2 meters) long. In between are the mid-sized northern and southern collared anteaters, also called tamanduas. Aardvarks, which are distantly related to elephant shrews, have a less extensive genetic tree than anteaters. Their species is the only one within the Tubulidentata order.
Aside from the tongue and snout, anteaters and aardvarks don't have much in common anatomically. Aardvarks are modified ungulates, or hoofed animals, with claws on their forelimbs. Anteaters have paws with large claws, and they have more fur than aardvarks. Anteaters exhibit a peculiar uneven gait to protect their 4-inch (10-centimeter) claws from wearing down. They tuck the claws up under their paws as though balling them up into a fist.
However, the primary difference between anteaters and aardvarks resides inside their mouths. Although they don't have incisors or canines, aardvarks have teeth. Because of the amount of dirt and sand that enters their mouth as a byproduct of rooting around termite mounds and anthills, their teeth continually grow to withstand damage caused by the grit [source: Myers]. For example, nearly half of one dead aardvark's stomach contents was sand [source: Redford]. Anteaters, on the other hand, have a number of primitive toothlike protrusions on the roof of their mouths called papillae, which help the animals grind up the ants [source: Cohn]. Their muscular stomachs take care of any further breakdown needed to digest these insects.
Anteaters and aardvarks evolved with similar mechanisms to follow their shared preferred diets. Yet, they remained distinctive enough so that we don't consider them to be related species. They both just happen to enjoy the scrumptious taste of ants and termites.
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More Great Links
- Cohn, Jeffrey P. "The Allure of Anteaters." Americas. November/December 2007.
- "Giant Anteater." Chicago Zoological Society. (Oct. 2, 2008)http://www.czs.org/czs/Brookfield/Exhibit-and-Animal-Guide/Tropic-World/Giant-Anteater
- Lumpkin, Susan. "Strange Joints: Anteaters, Armadillos and Sloths." Zoogoer. Smithsonian National Zoological Park. November/December 2007. (Oct. 2, 2008)http://nationalzoo.si.edu/Publications/Zoogoer/2007/6/Strange_Joints.cfm
- "Mammals: Giant Anteater." San Diego Zoo. (Oct. 2, 2008)http://www.sandiegozoo.org/animalbytes/t-anteater.html
- Mills, M.G.L. and Hes, Lex. "The Complete Book of Southern African Mammals." Struik. 1997. (Oct. 2, 2008)http://books.google.com/books?id=CavgCweI1nMC
- Myers, Phil. "Tubulidentata." Animal Diversity Web. 2000. (Oct. 6, 2008) http://animaldiversity.ummz.umich.edu/site/accounts/information/Tubulidentata.html.
- Redford, Kent H. "Curious Creatures to Whom the Ant is La Haute Cuisine." Smithsonian Magazine. August 1983. (Oct. 2, 2008)http://www.columbia.edu/itc/tc/mstu4031/ch06/pipes/article.txt
- Roy, Tui De. "The Strangest Creature I've Ever Met." National Wildlife Magazine. June/July 2003. (Oct. 2, 2008)http://www.nwf.org/nationalwildlife/article.cfm?articleId=781&issueId=62