One of the first mammals to use echolocation may not have been a bat or a whale, but an early ancestor of horses.
Hyopsodus was a weasel-like ungulate that lived 55 million years ago, around the time that bats are thought to have evolved echolocation.
of Montpellier University, France, and colleagues say that a new fossil cast of its braincase shows Hyopsodus had a large , a brain region enlarged in echolocating animals.
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They argue that Hyopsodus could echolocate: a skill that another group of ungulates 鈥� the whales, dolphins and porpoises 鈥� would not acquire for .
at Duke University in Durham, North Carolina, says the large inferior colliculus may just be a sign of sensitive hearing rather than full-blown echolocation, though. 鈥淚f an enlarged inferior colliculus is truly related to echolocation, then Hyopsodus potentially could have used rudimentary sound orientation,鈥� he says. 鈥淏ut calling it echolocation seems to be overstating the case.鈥�
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