This is a Skywalker Sound sound effect. It was created by Gary Rydstrom, and it debuted in The Lost World: Jurassic Park. Due to this being such a simple animal sound, it's very likely that one of Rydstrom's dogs was the one who made the sound. Links: https://soundeffects.fandom.com/wiki/SKYWALKER,_DOG_-_SMALL_WHIMPER#Audio_Samples