Bristletails are one seriously ancient critter. Tracks of Jumping Bristletails have been found in Permian rock (290 to 248 mya). There are two JB families worldwide, both families occur in North America, as do about 20 of the 350 to 450 of the world’s JB species. JBs live in a wide variety of conditions, from Arctic to desert, and they especially like leaf litter, bark, rock crevices, and rocky seashores. They are found in the nooks and crannies of the world, where they shelter during the day and perambulate at night.