Why would you believe that any other existence other than a human existence is "less"?
According to LDS theology, all other life forms are of a "lesser intelligence".
Why would I want to settle for less than what I already have ???
Truly becoming an eagle in the next life would be something less than what I already have..
One who does not see that is blind to what they already have and have the potential to be..
I have the potential to become a God, a creator of a universe, and eagle only has the potential to be an eagle, nothing more, and yes eagles and other animals will live on in another world too.
I have read NDE accounts of animals in the next life, in heaven/paradise, who are able to communicate with humans, via thought, and they are happy there, but they cannot become a god and create things... They are limited in what they can do..
Human exalted beings have no limits in the kingdom of God, which I am assured of in the next life.. I would not have that opportunity as any other life form.
Truly we can become Gods if we do what is required of us in this life.
Study out LDS theology, it's like no other doctrine found on this earth and of eternal worth and significance to the human soul..