Description: take a standard Grevy’s zebra, and make its stripes horizontal instead of vertical. Its legs and head are noticeably more muscular and bony than a regular zebra’s, too. Do not approach a speebra without protective gear.
Top speed: 95 mph burst, 40 mph cruising.
It is unclear why there is such a specific and sudden mutation among the wild Grevy’s zebra population. Possibly it’s because they’re endangered: evolution sometimes moves in mysterious ways. Mother Nature might have simply decided that more than doubling the speebra’s speed might help more of them survive to breed.
If that’s the (heavily anthropomorphized*) case, the results can best be described as a qualified success. Speebras can definitely outrun predators now, and even most powered off-road vehicles. They just haven’t figured out the best way to brake, yet. A speebra can take a remarkable bit of damage, at least from the front — and the species absolutely has to, because once one is up to speed it can’t always avoid immovable objects in time.
Speebras are also extremely ornery, with an aggression level that’s even higher than that of their unmutated cousins. They just don’t like humans, and have figured out that running into one results in a slightly bruised speebra — and a temporarily airborne person. The video footage of such encounters make for macabre, yet humorous, viewing… which might also be a survival trait, in this modern age. There’s already been at least one cable TV series.
*Evolution is in fact not supposed to work that way. But if the zoologists (not to mention, the increasingly more relevant cryptozoologists) are correct, nobody seems to have told evolution. There’s been a lot of weird critters out there lately, and they’re all speed-running the adaptation process…