Mouse spiders (Missulena) are ground-dwelling spiders recognized by their stocky build and distinctive bulbous head and jaw regions. These trapdoor spiders typically range from 10 to 35 millimeters in body length. They construct burrows in the ground, which serve as their primary dwelling and hunting grounds.
Their Native Lands
Mouse spiders are predominantly found across mainland Australia, inhabiting diverse environments but generally absent from Tasmania. While most species are indigenous to Australia, Missulena tussulena is also found in Chile.
Within Australia, their distribution varies by species. The Red-headed Mouse Spider (Missulena occatoria) has the widest distribution, occurring throughout mainland Australia, particularly west of the Great Dividing Range. This extensive reach is due to their spiderlings’ ability to disperse aerially by “ballooning,” a method uncommon among mygalomorph spiders. In contrast, the Eastern Mouse Spider (Missulena bradleyi) is typically found in Australia’s east coastal and highland regions.
Ideal Living Conditions
Mouse spiders thrive in a variety of habitats, ranging from open forests and bushland to semi-arid shrublands and even suburban gardens. Their presence in these diverse environments is influenced by the availability of suitable soil for burrowing. They generally prefer loose, well-drained soil, which facilitates the construction of their burrows. Many species are often located near water sources such as riverbanks, creeks, and other waterways.
The selection of these conditions is linked to the functional requirements of their burrows. These dwellings provide a stable microclimate, offering protection from extreme temperatures and maintaining adequate humidity levels. The soil type also impacts the integrity and stability of the burrow structure, ensuring a secure refuge. These environments support a supply of prey, allowing the spiders to ambush insects and small invertebrates from the safety of their burrows.
Their Subterranean Homes
Mouse spiders construct characteristic silk-lined burrows that extend vertically into the ground. The depth of these burrows can vary, with those of the Red-headed Mouse Spider reaching 20 to 55 centimeters, though many are typically around 30 centimeters. The entrance to these burrows is often concealed by one or two surface trapdoors, which are camouflaged with soil and silk to blend with the surrounding ground.
For certain species, such as the Red-headed Mouse Spider, the burrow features two trapdoors positioned almost at right angles to each other. These doors can be thin and wafer-like or thick and plug-like, enhancing both prey capture efficiency and concealment. Within the main shaft, a side chamber is often present, providing a secure space for egg sacs and spiderlings, as well as a safe retreat from predators. Trip lines made of silk may extend outwards from the entrance, enabling the spider to detect vibrations from approaching prey or potential threats, facilitating their ambush hunting strategy. Female mouse spiders typically remain within these burrows for their entire lives, while males venture out during the breeding season to seek mates.