why-animals-do-the-thing:

typhlonectes:

When the sun goes down on the forests of Vietnam, a small, secretive
rodent emerges from the darkness and begins zipping across tree branches
in search of fruit and seeds.

Typhlomys, also known as the
soft-furred tree mouse or Chinese pygmy dormouse, is around three inches
long and sports a white-tufted tail longer than its body. But it darts
so fast that, to the human eye, it appears as little more than a
nocturnal blur.

That’s especially impressive, because Typhlomys is almost completely blind.

When scientists looked at Typhlomys eyeballs under a
microscope, they quickly learned that its visual organs are a total
mess. Irregular retinal folds “destroy continuity of image projection,”
researchers wrote, while a reduced space between the lens and the retina
mucks up the animal’s ability to focus. They also have a reduced number
of image-receiving ganglion cells, which are usually an indicator of
perception. The arboreal rodents seem capable of determining the
difference between light and dark, but little else.

So how does Typhlomys avoid falling to its death or running straight into the jaws of a predator?

According to a paper published in Integrative Zoology
last December, this long-tailed furball has a trick up its sleeve: It
emits ultrasonic chirps, and then navigates its environment based on the
echoes that bounce back.

If that sounds a lot like another nocturnal
mammal, you’re right: Some scientists believe that Typhlomys might be a sort of “transitional animal” that could be the key to understanding bat evolution.

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This is so cool. 

This Echolocating Dormouse Could Reveal the Origins of One of Nature’s Coolest Superpowers