What colour is Beatrice the rat?

Some say she is panelwhite as a labcoat or as innocence,
except for the pink of her eyes, nose, tongue,
and the red of her bloodjuice pulsing like little hammers.
Others say she is brown as thought, brown as dust,
dogbrown, shadowbrown, scurryrun brown,
dun as old sand and whisperleaf, brown as betrayal.
Others still that she is seablack like the tang of old timbers,
clawblack, dark doorway-black, deathblack.

‘Her sheen shifts,’ says Mr Coelacanth.
‘Like the threads in my mohair stride.’

Marie Marshall