Let’s talk about the first animal in the alphabet. Not only is it all alone up there at the top of the dictionary, but it’s all alone in its genetic family, a single fruit hanging from the end of a dead taxonomic branch. But although it may be alone in its immediate family, it’s got the weirdest extended family you’ve ever seen.
“A” is for Aardvark. Like the anteater, its super-thick skin protects it from insect bites as it burrows into anthills and termite mounds with powerful, clawed forearms and licks up their inhabitants with a long, sticky tongue. The resemblance to anteaters, however, is what we call “convergent evolution;” there’s no relation between the African Aardvark and its South American equivalent. In fact, there’s no relation between the aardvark and anything else. It’s the lone species in the Order Tubulidentata (“tube teeth”). To realize how lonely that is, consider that our Order is “Primates,” and imagine if humans were alone in the world without apes, monkeys, or lemurs.
A world without monkeys makes me sad.
However, “A” is also for Afrotheria. That’s the name of the Super-Order (a group below “Class” and above “Order”) to which aardvarks belong. And Afrotheria is an extraordinary example of evolutionary radiation, a single family exploding into a multitude of different forms. And my, oh my, does the aardvark have a strange extended family.
The Golden Mole
The Elephant Shrew
and the Manatee.
Certain rogue taxonomists as early as the 1920’s had suspicions that these were related, based on things like ankle bones and late-stage tooth eruption. But the scientific community didn’t accept that all these animals could be related to a common ancestor until advanced genetic testing sealed the deal in the late 1990’s. After all, you’d be crazy to believe that a sightless, sand-burrowing mole, one of the world’s smallest creatures, could be related to the largest land animal on Earth, capable of knocking down tall trees. Or that an enormous aquatic herbivore shared a family reunion with a trunk-nosed racing shrew or a rock-hopping, semi-arboreal marmot.
But now that you know it, how can you not be amazed at the creativity of evolution, the plasticity of life, how far the apples can roll from the tree? How can you not be amazed that a long-lost ancestor could become a genetic supernova, scattering descendants of all shapes and sizes from the Saharan desert to the Siberian seas? We humans share 99% of our genome with chimps, and 85% of our genome with mice. We, too, are close and distant cousins with so many bizarre and beautiful mammals. I suspect that somewhere in the vicinity of hundredth-cousin a million-removed, we’d even find the lonely aardvark.