Steve
Mostly Harmless
There’s a classic episode of The Twilight Zone about this called The Hunt.Unfortunately the Christian belief is that animals do not have souls and therefore cannot go to heaven!
On the other hand, in the Hindu epic, The Mahabharata, the ‘hero’ , after his terrible trials and tribulations, refused to enter heaven because his dog was not allowed in. As he walked away with his faithful friend it proved to be a test which he passed and they both entered together.