Insectivorous mammal (8)
(Other definitions for aardvark that I've seen before include "African burrowing animal, feeds on termites" , "African nocturnal burrower" , "First creature found in a dictionary" , "First animal to be found in a dictionary?" , "among Chambers' top words!" .)
'insectivorous mammal' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for anteater that I've seen before include "Termite muncher" , "Long-tongued mammal" , "individual living off workers" , "Sticky-tongued mammal" , "Feeder on termites" .)