Does the scriptures say where they go after death? Do animals go to heaven like humans?
All of us go through millions of births in sub-human forms before getting human form. So animals ultimately get a human body. Animals don't go to heaven or hell or attain moksha. Only humans can go to heaven or hell or attain moksha.
In the eighty four lacs of bodies of creatures one does not acquire true knowledge anywhere unless one is born as a man.
Here, after thousands of crores of births a creature obtains human form only sometime due to aggregate of virtue.
Having obtained a rare human form he should endeavour for moksha. If he does not endeavour for it, there can be no greater sinner in the world.
Born in the most beautiful human form he incurs the sin of slaying a Brahmin if he neglects his self.
Without human body it is not possible to obtain the supreme goal. One should be, therefore, very cautious to guard wealth in the form of his body and perform good actions.
So far as this body remains intact he should practice dharma. One is a perfect fool who digs a well only when the house is on fire.
[Garuda Purana, Dharma Khanda, Chapter XLIX]