Rondors were a species of bovine-like creatures that grazed fields of plants on Krypton.[1]
History
Rondors were kept in fields below the House of El Citadel when Kal-El was born in 1980, able to hear the infant Kryptonian's cries.[1]
It is also rumored that Nam-Ek was so inhumanly huge and muscular primarily because he was born as the result of mixing the DNA of a Kryptonian with that of a Rondor beast.[2]