Bloomer, feeding caribou’s tail to dangerous reptiles (6)
I believe the answer is:
crocus
'bloomer' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
(Other definitions for crocus that I've seen before include "Spring-flowering plant" , "Bulbous plant with brilliant coloured flowers" , "Slow transition" , "Early flowering bulb" , "Occurs (anag.)" .)