Tiny speedsters build their own highways
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Elephant shrews — including so-called “giant” species the size of a squirrel — are more closely related to elephants than to shrews. As for their basic lifestyle, elephant shrews may be more like really mixed-up antelopes.
“Take an antelope and an anteater and slap them together,” says Galen Rathbun of the California Academy of Sciences in San Francisco.
Elephant shrews, or sengis, are native to Africa and, like antelopes on the savanna, “run like the wind,” Rathbun says. Mated pairs often clear long, straight paths through their territories and bound along them when a hawk looms. Smaller sengi species spend a lot of time clearing twigs or other high hurdles off the potentially lifesaving speedways. (This video of the Rufous elephant shrew shows the animal using paths to evade predators and hunt for insect prey.)
Also like antelopes, baby sengis often don’t need a lot of babying. In many species they’re up and moving an hour or two after birth. And sengis have high-crowned teeth, common in plant-grazers that grind tough vegetal stuff. Yet the little mammals don’t gather in herds and don’t even graze, instead snuffling around for small invertebrates, especially ants.
Their long bendy noses look like tiny elephant trunks, but they’re less flexible and can’t pick things up. To snatch an ant, a sengi shoots out a skinny tongue from its mouth, which lies far back toward the neck. To work around all that nose, sengis sometimes turn their heads and slurp sideways. “They’re really sloppy eaters,” Rathbun says.
The rest of the body isn’t very elephant-like either, Rathbun says. The connection comes from DNA analyses that place elephant shrews in the Afrother--ia group with real elephants, sea cows, aardvarks and some other African mammals. “They’re not closely related, but they’re more closely related to one another than to anything else,” he says.
A new DNA analysis by California Academy’s John Dumbacher has helped add a new sengi species to the previously known 18. Described in the June Journal of Mammalogy, the latest (distant) cousin of an elephant is the smallest sengi yet, weighing in adulthood less than a newborn kitten.