The Land Crustacean Carrying Its Own Ocean

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 tiny white patches called pleopodal lungs. These are modified gills that must stay damp to pull oxygen from the air. 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. The young spend their first weeks swimming in a private nursery before they ever take their first breath of air.