https://www.pcgamesn.com/red-dead-re...orse-testicles

Specifically, Stephen Totilo writes “After seeing the game’s first trailer, we and other had wondered if the horse’s testicles were animated. I asked, and they [Rockstar] told me that the testicles shrink and expand depending on the temperature in the game world. Details, details.”
GOTY 2018 for sure