This sound effect can be found on Lucasfilm Sound Effects Library, which was made by Sound Ideas. It is a Skywalker Sound sound effect that was recorded by Ben Burtt and his team for Star Wars: Episode V - The Empire Strikes Back (1980) for the wampa. According to Ben Burtt in a recent interview , “There were some good elephant roars that we got at the Oakland Zoo that were used for the wampa when it really yells.” Links: https://soundeffects.fandom.com/wiki/Sound_Ideas,_ELEPHANT_-_VARIOUS_SNORTS,_GROWLS,_TRUMPETS,_ANIMAL#Audio_Samples