"Cockle."
The Oxford dictionary:
1. an edible burrowing bivalve mollusc with a strong ribbed shell.
Why, yes. The definition includes "edible."
I haven't searched every related definition, but I checked the definitions of "human," "ape," and "mammal," and – counter-intuitively, perhaps – found "edible" in none of them.
A puzzle?
(Note: I use it routinely regardless, but in this case, I used the "Oxford comma" slightly more consciously.)
(Note: I've observed the BBC phrases some headlines as questions, perhaps to keep them journalistic, according to their estimation.)