Head to head
Red King Crab vs Japanese Spider Crab
Red King Crab
VS Japanese Spider Crab
Both are enormous, cold-water crab-like crustaceans, but only one of them is actually a true crab.
| Red King Crab | Japanese Spider Crab | |
|---|---|---|
| Scientific name | Paralithodes camtschaticus | Macrocheira kaempferi |
| Leg span | Up to nearly 2 metres | Up to 3.7 metres, the largest of any arthropod |
| True crab status | Not a true crab, closer to hermit crabs | A true crab |
| Visible walking leg pairs | Three pairs | Four pairs |
| Notable behaviour | None comparable documented | Decorates its shell with sponges and anemones |
| Lifespan | Not well documented | Possibly up to 100 years |
| Conservation status | Least Concern | Least Concern |
| Habitat | Ocean | Ocean |
Red King Crab vs Japanese Spider Crab: common questions
Which has the larger leg span, the red king crab or the Japanese spider crab?
The Japanese spider crab has the larger leg span by far, reaching up to 3.7 metres and holding the record for the largest leg span of any living arthropod, compared with the red king crab's still-impressive span of nearly 2 metres.
Is the red king crab a true crab like the Japanese spider crab?
No, the red king crab belongs to Anomura, making it more closely related to hermit crabs than to genuine crabs, while the Japanese spider crab is a true crab, part of the group Brachyura.
Which one decorates itself for camouflage?
The Japanese spider crab is the decorator of the two, attaching sponges, anemones, and kelp to its shell for camouflage and chemical defence, a behaviour not documented in the red king crab.