Woodlice carry tiny oceans on their backs

The woodlouse crawling through your garden soil is actually breathing through gills. Because it is a crustacean and not an insect, it requires constant moisture to survive on dry land.

Look at its underside and you will see the structures it uses to breathe. Woodlice have modified gills; while some species have developed 'pleopodal lungs' to breathe in drier air, they still generally require high humidity to prevent their respiratory surfaces from failing. If a woodlouse dries out, it effectively suffocates while standing in open air.

To manage this, they live in a state of constant dehydration defense. They huddle together to create a micro-climate of humidity and can even drink water through their rectums using tube-like structures called uropods. They are essentially deep-sea creatures that phased into your backyard, carrying a thin film of the ocean with them to stay alive.

While they have adapted to land, they never developed the waterproof wax coating that insects use. This lack of armor means they lose water faster than almost any other land-dwelling creature. They spend their entire lives on a knife's edge between breathing and evaporating.

Even more bizarre, mother woodlice carry their offspring in a fluid-filled pouch called a marsupium, which provides the developing young with the aquatic environment they need before they emerge. The young spend their first weeks in a private nursery before they ever take their first breath of air.