The Sow Bug Natural History
Size
These beetles can grow up to 6 – 19mm.
Habitat and Distribution
They come from Europe and spreading to North America, Africa, Australia, and Asia. Sow bugs are terrestrial crustaceans that require high-moisture, dark, and sheltered habitats to survive, often found under mulch, leaf litter, rocks, logs, or in compost. As nocturnal scavengers, they prefer humid, cool spots, often invading damp basements, crawl spaces, or garages. They need constant moisture for their gill-like breathing organs.
Diet
Sow bugs are terrestrial crustaceans and detritivores that primarily feed on decaying organic matter, such as rotting leaves, wood, and plant debris.
Groups and Breeding
They are considered gregarious, meaning they prefer to live in groups rather than alone. As terrestrial crustaceans with gill-like breathing organs, their “social” behavior is primarily a survival mechanism to manage moisture, protect against predators, and navigate their environment. Sow bugs tend to aggregate, or “huddle,” together, particularly when their environment becomes dry or hot. This behavior reduces the surface area exposed to the air, slowing the evaporation of moisture from their bodies and preventing them from dying. Sow bugs reproduce throughout the whole year, with females producing 25–75 young per brood, two to three times annually, often peaking in spring. They require high moisture, with females carrying fertilized eggs in a pouch (marsupium) for 3–9 weeks before releasing nymphs that mature in about one year.
Threats
They are threatened by predators and environmental conditions. As they breathe through gill-like organs and lack a waxy cuticle to prevent dehydration, their main environmental threat is drying out
Interesting Facts
Sow bugs (also known as woodlice or roly-polies) are actually terrestrial crustaceans—not insects—making them more closely related to lobsters, crabs, and shrimp.
The Sow Bug During Your Day Out in Kent
The Sow Bugs at Wingham Wildlife Park can be seen in the Bug Garden area of our park. This area is home to a wide variety of invertebrates including Red-clawed Crab, Tarantulas, cockraoches and stick insects to name but a few.