Large rodent? Better to prevent one crossing yard (8)
I believe the answer is:
capybara
'large rodent?' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for capybara that I've seen before include "Large South American rodent" , "Largest rodent" , "largest animal of its kind" , "Pay a crab (anag) - rodent" .)