Barrens Jumper

"...So, there I was last of my water skin gone, food bag empty, deep in the barrens; probably deeper than any sane man has gone before. Well wouldn't you know it, I started praying right there and then, Kerys, Kore, Aethlyn, damnation I even prayed to Pallura! Asked for anything, something, just enough food to get me out of this dreadful place and the next thing I see is this tiny mouse, as small as a halflings eye, and its sitting there next to my boot nibbling on some of this green stuff on the under side of this rock. So, I sit and watch it for a time, skittish little thing it was, it sat on its tail like the springs on a wagon. Would've only been a mouthful but gods I was grateful. So I lean forward to catch the critter and POP! its gone, flying off into the distance, flying on its little ears and sailing clean out of view. Well, of course I didn't eat the mouse but it did show me I could eat that moss! and that's how I survived! 16 days of licking rocks and I made it back..."               Account of Dvar Mcresh, Human woodsman, on how he traversed the barrens C. 598

Overview

The Barrens Jumper is a small mouse-like creature thought to be native to the wallowing barrens. Elusive, small and skittish their existence currently has not been confirmed and as such, they are thought to be a fabrication of delirious minds that have spent too long within the barrens.  
Said to be able to leap forward up to 100 ft. at a time these creatures seem to defy conventional biology.

Distinguishing Features

The Barrens Jumper is said to have pale grey fur, likely to allow it to blend into the surroundings of grey rock it finds itself it. Its tail is said to be over 5 times its body length and used as a spring to allow it to jump as far it is does, so, oftentimes when seen the barrens jumper, if indeed it has been seen, appears to have a much shorter tail.
They are said to have large, much larger than they should be ears, which it is thought to use to allow some rudimentary form of gliding allowing it to jump further.

Diet

The Barrens Jumper must surely survive by eating what little moss and lichen grow within the barrens. As little else is known to grow here. Some scholars have theorized that it may use its incredible jumping power to attack flying insects, however, this has not been observed or proven.