Did you know? Some sea otters eat so many purple sea urchins over their lifetime that their teeth and bones actually become stained purple (known as echinochrome staining).

 

Sea otter with purple sea urchin

Sea otter resting on the ocean surface, grasping a purple sea urchin it has just pulled up off the ocean floor.

 

Sea otter skull with echinochrome staining.

Sea otter skull with echinochrome staining.

 

Sea otter teeth with echinochrome staining

Stranded sea otter with echinochrome stained teeth.

 

Purple sea urchins on rocky reef amid kelp forest.

Purple sea urchins on rocky reef amid kelp forest.