Scotophaeus blackwalli

Scotophaeus blackwalli: The Enigmatic Mouse Spider


Scotophaeus blackwalli, commonly known as the mouse spider, is a fascinating species belonging to the Gnaphosidae family. Despite its common name, the mouse spider is not related to the notorious Australian mouse spiders from the Actinopodidae family, which are known for their venomous bite. Instead, S. blackwalli is a harmless yet intriguing species native to Europe. In this article, we will explore the taxonomy, morphology, behavior, distribution, and ecological significance of Scotophaeus blackwalli.

Taxonomy and Distribution

Scotophaeus blackwalli is a member of the Scotophaeus genus within the Gnaphosidae family, commonly referred to as ground spiders. The mouse spider is widespread across Europe, extending from the United Kingdom to Russia. It is commonly found in a variety of habitats, including gardens, meadows, forests, and grasslands.

Morphology and Appearance

Scotophaeus blackwalli is a medium-sized spider, with females measuring 9-12 mm in length and males slightly smaller at 7-9 mm. Both sexes display a brown to black coloration with a velvety texture, which lends the spider its common name. The cephalothorax and abdomen are generally uniform in color, though some individuals may exhibit faint patterns or markings.

The mouse spider has eight eyes arranged in two rows, with the anterior row being slightly procurved. The legs are relatively long and slender, allowing for agile movement when hunting prey.

Behavior and Ecology

Scotophaeus blackwalli is a nocturnal hunter that relies on its excellent vision and stealthy movements to capture prey. It is a ground-dwelling species that does not construct a web for prey capture. Instead, it actively searches for insects and other small invertebrates, which it immobilizes with a venomous bite. The venom of S. blackwalli is not considered dangerous to humans.

During the day, the mouse spider can be found hiding under stones, logs, or leaf litter, where it creates a silk retreat for resting and molting. S. blackwalli is a solitary species, with individuals only coming together during the mating season.

Reproduction in Scotophaeus blackwalli occurs in spring and early summer. Males roam in search of females, engaging in courtship displays to attract a mate. After mating, the female lays her eggs in a silk sac, which she then guards until the spiderlings hatch. Once hatched, the spiderlings disperse to find their own territories.

Ecological Significance

Scotophaeus blackwalli plays an essential role in the ecosystem as both predator and prey. As a predator, it helps to maintain a balance in insect populations, contributing to the overall health of its habitat. At the same time, the mouse spider serves as a food source for various larger predators, including birds, mammals, and other arachnids.


Scotophaeus blackwalli, the enigmatic mouse spider, is an intriguing species that highlights the fascinating diversity found within the world of spiders. Despite its unassuming appearance, the mouse spider plays a vital role in maintaining the delicate balance of its ecosystem. By understanding and appreciating the importance of such species, we can contribute to the conservation of biodiversity and the preservation of the intricate web of life that sustains our planet.

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