There is no indication in Scripture that animals will be in heaven. Animals do not have a spirit (as humankind does), and so when they die that is considered the end of their total existence. We did not evolve from monkeys as taught by evolution. Humanity was created by God and given authority over all such earthly creatures, utilising them for ours own benefit, to carry and pull loads, using their wool, and consuming their milk and meat (Gen 1:26). As they are part of God’s creation, they should be respected and not mistreated or subject to unnecessary pain or hardship. Some people give their pets’ undue and unwarranted affection; this is misdirected love.
In the OT animals were used in sacrifices to God, their lives being forfeited to cover the sin of mankind.