Mouse spiders are a kind of Trapdoor spider. Females are up to 3cm long, very stocky with short, thick legs; they are black or dark brown. Males are 1-2cm long, with longer legs and long palps which look like an extra pair of legs. Both sexes have enormous fangs and fang bases. A diagnostic structural feature is the very steep slope on the back of the head area. Male Red-headed mouse spiders (Missulena occatoria) have a red head and jaws and blue abdomen, while male Eastern (M. bradleyi) and Northern (M. pruinosa) mouse spiders have a whitish patch on the top of the abdomen.
Mouse spiders live in burrows in the soil, sealed with a hinged lid. The burrow provides a refuge from predators, parasites, low humidity and high temperatures. The spider feeds by lunging at passing prey from the burrow entrance. A female mouse spider is long-lived and will spend her entire life in the burrow - she is rarely seen except when accidentally dug up. On the other hand, males leave their burrows at maturity (a couple of years old) to search out a mate, usually after rain. Mating takes place in the female's burrow, after which the male dies. A disturbed Mouse spider will rear up defensively in a similar way to the Funnelweb.
Although few serious bites have been recorded, there is some indication that Mouse spider venom is very toxic, so the spiders should be treated with caution.
If considered necessary, individual spiders can be killed as they are found. Mouse spiders numbers are seldom high enough to warrant any concerted control measures.
If serious symptoms occur after a bite, Funnelweb spider antivenene may be effective.