Mouse spiders, belonging to the genus Missulena, are large arachnids native to Australia. They are known for their robust bodies, shiny carapace, and powerful chelicerae, or jaws. The common name, mouse spider, comes from an old and now disproven belief that they dig deep, mouse-like burrows in the soil. While they are burrowing spiders, their underground homes function as a permanent shelter and hunting ground. This article details the specific geographical areas where these spiders live and the engineering involved in constructing their subterranean domains.
Global and Regional Range
The vast majority of the approximately 12 recognized species of mouse spiders are endemic to Australia, distributed across the entire mainland continent. Their range extends from the tropical north to the temperate south, inhabiting a diverse array of environments. The Red-headed Mouse Spider (Missulena occatoria) has the widest distribution, found across most of mainland Australia, particularly west of the Great Dividing Range. The Eastern Mouse Spider (Missulena bradleyi) is commonly found along the eastern coast, including New South Wales, Queensland, and parts of Victoria and South Australia. Other species, such as the Northern Mouse Spider (Missulena pruinosa), occupy more specific territories in the northern parts of the continent.
Preferred Soil and Environmental Conditions
Mouse spiders exhibit adaptability, settling in habitats ranging from open forests and woodlands to semi-arid shrublands. Their choice of location is heavily influenced by the ground conditions necessary for building a stable burrow. They frequently establish their homes in soft soil, often near sources of moisture like the banks of rivers, creeks, or other waterways. The presence of water is beneficial, as the moisture helps to consolidate the soil, making it easier to excavate and less prone to collapse.
The subterranean environment they create provides stable temperatures and low humidity, protecting the spider from harsh surface weather. Female mouse spiders are especially reliant on their burrows, rarely leaving them throughout their lives. The need for undisturbed ground explains why they often select areas of natural bushland or established edges. Only the wandering males temporarily leave the safety of their burrow during the breeding season to search for a mate.
The Architecture of the Mouse Spider Burrow
The construction of the mouse spider burrow is a sophisticated structure designed for both defense and ambush hunting. The basic structure is a deep, vertical shaft that can extend 20 to 55 centimeters into the ground in larger species like the Red-headed Mouse Spider. The entire shaft is meticulously lined with a layer of silk, which helps to stabilize the walls and prevent the surrounding soil from collapsing into the tunnel.
A distinctive feature of the burrow is the presence of one or sometimes two trapdoors at the surface, constructed from a blend of silk and local soil particles. These lids are perfectly camouflaged to merge with the surrounding ground, making the entrance difficult for predators or prey to detect. Deep within the main shaft, the female spider constructs a side chamber that branches off the main tunnel. This lateral chamber serves as a safe haven from floods or predators, and provides a secure location for depositing the egg sac. The female utilizes the burrow for protection, thermoregulation, and as a strategic point from which to ambush small prey.