The lesser Egyptian jerboa is bipedal in locomotion. Its hind limbs are roughly four times the length of the forelimbs, and the three central metatarsals are fused into one cannon bone. Fusion removes joints that would flex and waste energy, stiffening the foot into an efficient spring while keeping distal mass low, which matters because weight at the end of a swinging limb is disproportionately costly.
The gait is not simply fast. Jerboas move in unpredictable zigzag hops, and this erratic path is generally read as an anti-predator tactic against owls and foxes that must intercept rather than chase. The long tufted tail acts as a counterweight and a prop.
The desert physiology is equally strict. Jerboas typically drink no free water, extracting what they need metabolically from seeds and plant material, concentrating urine heavily, and spending the day in a plugged burrow where humidity stays higher and temperature lower than the surface.