Why Are Isopods Called Woodlice?
The name “woodlouse” often surprises people because isopods are not lice at all. Discover where the name came from and why these crustaceans are commonly found living in wood and leaf litter.
Why Are Isopods Called Woodlice?
Isopods are commonly known by several different names depending on where you live. In the UK they are often called woodlice, while in other countries they may be known as pill bugs, roly-polies, or sowbugs.
The name woodlouse can sound strange, especially because isopods are not actually lice. In fact, they are crustaceans more closely related to shrimp and crabs.
So where did the name come from? The term woodlouse developed simply because these small animals are frequently found living in wood, leaf litter, and other damp natural materials on the forest floor.
The Meaning Behind the Name Woodlouse
The name woodlouse is made up of two parts:
- Wood – referring to the places where these animals are often found, such as rotting wood or logs
- Louse – an old English word used historically for small crawling creatures
In earlier centuries, people often used the word “louse” to describe any tiny insect-like animal that crawled on surfaces. Over time the name stuck, even though scientists later discovered that woodlice are not insects at all.
If you want to learn more about their true classification, see our guide explaining whether isopods are insects or crustaceans.
Why Woodlice Live in Wood and Leaf Litter
Woodlice are usually found in damp environments where they can stay cool and moist. Their bodies still rely on moisture because they evolved from aquatic crustaceans.
In nature they are commonly found under:
- Rotting logs
- Fallen branches
- Leaf litter
- Stones
- Moss
These environments provide shelter, food, and the humidity they need to survive.
When keeping isopods in captivity, recreating these conditions helps colonies thrive. Many keepers add natural materials such as:
- Leaf litter which acts as food and cover
- Cork bark to create hiding places
- Live moss to help maintain humidity
Woodlice Are Actually Crustaceans
Although the name woodlouse suggests an insect, these animals belong to a completely different group.
Isopods are part of the crustacean class, which also includes animals such as:
- Crabs
- Shrimp
- Lobsters
They are one of the few crustaceans that successfully adapted to life on land. This adaptation allows them to live in forests, gardens, and soil environments around the world.
Different Types of Woodlice
There are many different species of woodlice, and they can vary greatly in size, colour, and behaviour.
Some of the most well-known types include:
- Armadillidium – often called pill bugs because they can roll into a ball
- Porcellio – fast moving species commonly found in gardens
- Oniscus – common rough woodlice found in the UK
Many of these species are now popular among hobbyists who keep them in terrariums and bioactive setups.
You can explore a variety of species in our isopod collection.
Why Woodlice Are Important in Nature
Woodlice play an important role in ecosystems as decomposers. They feed on decaying organic matter such as leaves and wood.
By breaking down this material they help recycle nutrients back into the soil, supporting plant growth and maintaining healthy forest ecosystems.
This behaviour is also why isopods are commonly used in bioactive terrariums, where they act as part of the clean-up crew that breaks down waste.
You can learn more about this role in our guide to why isopods are important in bioactive setups.
Why the Name Still Exists Today
Even though scientists now classify these animals as crustaceans, the name woodlouse has remained in common use.
This is mainly because the term has been used for centuries and is widely recognised in everyday language.
Scientific names such as Isopoda are more precise, but common names like woodlice continue to be used in gardening, education, and general conversation.
Final Thoughts
Isopods are called woodlice because they are commonly found living in wood, leaf litter, and damp forest environments. The name dates back centuries and was originally used to describe small crawling creatures found in wood.
Despite the name, woodlice are not insects or lice at all. They are land-dwelling crustaceans with fascinating behaviours and an important role in nature.