At a glance
Essentials
- Activity
- Arm autotomy is a defensive response.
Observation guide
What to look for
- 01
A sea star with arms; it can shed one or more of them through defensive autotomy.
An important limitation
Lighting, age and viewing angle can hide features. If identification affects consumption, handling or conservation, consult specialist sources.
Ecology
Description and characteristics
Asterias rubens is a sea star in the class Asteroidea. It can shed one or more arms as a defensive response, a process known as autotomy.
Mutable collagenous tissue is involved at the separation site. Its mechanical properties can change rapidly under the control of the nervous system, weakening that area and allowing the arm to detach.