Adults are 3 - 4 in. long (including their legs) and are covered in dark brown hair with spots of black on their abdomens. They have a very acute sense of smell and can move from place to place with surprising speed.

After mating in the spring, females begin to look for locations to lay their eggs－ venturing throughout human households to reside under beds or on bedroom walls. At night, the spiders wait for the scent of food to alert it of a human’s mouth; then, they amble towards it.

A Tongue Bunny either crawls into an open mouth or slides between one’s lips, quickly releasing its eggs into a hastily spun sack. The mouth’s moisture and chemical makeup activates the hatching of the spiderlings, who spring from their web basket; during the birth, there can be anywhere from 20 - 70 individual Mouth Spiders lain. Tongue Bunnies are matriphagous－with the mother sacrificing her body to her offspring; quickly, ravenously, the hatchlings consume her entirely, and move as one outside of the mouth. The youths travel together for a month, exiting the house and living outdoors under buildings or in the shadows of debris. They reach maturity after thirty days, and separate.

The next spring, the arachnids move indoors to look for mates, repeating the cycle. Males wait in areas where they expect to encounter females, such as in kitchens and bedrooms. As females die after birth, males make up most of the population; males may live up to five years, while females may live up to three, if mates are difficult to find.

Tongue Bunnies get their name from the dust bunny-like casings they leave behind in the mouth. The silk webbing swells and grays, resembling a dusty, hairball; the substance may also make the host’s teeth or cheeks feel as if they have a film on them. Pieces of the female spider, as well as unhatched, deformed, or accidentally crunched/smashed spiderlings may be found intermingled within the egg sac. Though their bodies are tough, it is not uncommon for mothers to be harmed or killed while laying; this, however, does not completely impede her spiderlings. If unborn, a fraction of the youths eat their way out from her corpse. On average, all spiders are only in the mouth for an hour and a half.