Answer by Anthony Sargeant:
Why should it stop being a "threat" to itself?
If one takes that to mean the "threat" that the animal species which we call homo sapiens might become extinct. Plenty of other species have become extinct over time – sometimes simply because they have become trapped in an evolutionary cul-de-sac (the Giant Panda is heading that way in our present age).
Homo sapiens are just another animal species which might destroy itself in one way or another. In the absence of homo sapiens other animal species would survive, some would thrive and new ones would arise.