Giant Isopod
Weirdness 8/10

The deep-sea roly-poly the size of a cat that can fast for years

This deep-sea creature is a roly-poly the size of a cat — and can go years without eating.

📋 Fact File
🐾 Crustacean🍽️ Carnivore (scavenger)
📏 Size
Up to about 50 cm (20 in) long
As big as a pet cat or a small dog.
Lifespan
Not fully known - likely several years
Not EvaluatedThese deep-sea creatures live so far down that scientists haven't studied them enough to give a Red List rating.
🤔 Guess first

Which one is REALLY true about the Giant Isopod?

The short version

ages 9–12

The giant isopod is a deep-sea relative of the pill bug that grows to cat size. It scavenges carcasses that fall to the seabed, can gorge on a single huge meal (like a dead whale) and then survive years without eating — one famously refused food for over 5 years. It curls into an armored ball when threatened.

Why it's so weird

  • The Giant Isopod is a deep-sea relative of the little pill bugs you find under garden rocks.
  • The Giant Isopod grows to about the size of a house cat.
  • The Giant Isopod scavenges dead animals that drift down to the cold, crushing ocean floor.
  • The Giant Isopod can gorge on a single huge meal, like a dead whale, then survive years without eating.
  • The Giant Isopod curls up into an armored ball when threatened, just like its tiny garden cousin.
📏 How big is it, really?
Giant Isopod
50 cm
Giant Isopod
a 7-year-old
1.2 m
🧒

You could line up about 2 of them along a 7-year-old!