I get asked "Does Animal Ghosts exists?" alot. And the answer is yes.
Alot of animal ghost were family pets. So one possibility is that the owners is keeping them here. They wanted to see them again or emotional stress can keep them here.
Most animal ghosts are dogs, cats, and horses. This ethier means that the animals that were mostly near humans or that animals with a higher brain functions is the ones that are most likely to become ghosts.
I also see ghost cows running/walking around my house. They were taken care by Lizzy and her dad (a.k.a the other two ghost in my house).
It is hard for paranormal investigators to know if thier is a ghost animal. Most animal sounds can be easily confused by everyday sounds. It is also very hard to have a convsation with an intelligent animal ghost.
Be careful, because you could also be hanging around a demonic being. If you hear it make any growling sounds, it can be a demonic or evil being. Animal ghost dosen't usually growl, but the demonic beings do.