“And dogs. “
At no time is salvation mentioned as being offered to anyone but people.
Not even angels get an offer of salvation.
The only Created beings in rebellion are human. Being the pinnacle of His Creation, we were and are offered salvation. The rest of His good Creation doesn't need it, never having rebelled. They suffer disease, aging, decay and death, right along with us, because of us, due to The Fall. All the world does.
A good resource regarding this matter comes from the 18th century. It's John Wesley's legendary sermon, The General Deliverance. It's very powerful, and runs the gamut of Biblical thought pertaining to the lesser Creatures. Give it a look, it's widely available on the internet.
Then count me out.
“Not even angels get an offer of salvation.”
And I see no one arguing that angels will not be in heaven.
I believe there will be many aspects of God’s creation that do not require salvation but will be in heaven...