Fast Australian runners (4)

I believe the answer is:

emus

(Other definitions for emus that I've seen before include "Aussie birds" , "Large flightless birds of Australia" , "Fast, but not high-fliers" , "Largest native Australian birds" , "laboratory units" .)

I've seen this clue in the Newsday.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.