Why do all lifeforms desire to survive?

I don't believe that all humans desire to survive. I read about writers who commit suicide. So I do not believe that all humans want to live. When I was around 28 or 29 years old, I often think about suicide. But that may not mean I am pessimistic. I do not like pessimistic person. So I feel my desire to kill myself is not pessimistic one. It is just a desire, I do not feel I am useless. So I do not believe that all humans desire to live. Nor do I think suicide is immoral. I do not think suicide is wrong. I do not think suicide is right either. I feel artists may have larger chance of commiting suicide.

Humans desire to survive for the most part, and sometimes, at some points in life they do not desire it, which not necessarily ends in suicide. Even if not wanting to live, people do try to avoid daily: hunger, cold, heat, shame, fear, stress, pain, etc. If they do not constantly think or act as "desiring to survive", they inevitably are caught up in avoiding negative physical and emotional feelings, and if they do not strive to avoid having them, those conditions would eventually lead to sickness and death.

I only know that smelling the thick, moist air at a beach in Bali, while being served a cool Long Island Ice-Tea, watching the surfers ride the waves, while feeding the monkeys peanuts watching them quickly cath them in mid-air, is pretty good.

Loving another person in passion, who is worth dying for, gives me a desire to survive.

A cannot speak for the monkeys, but they sure loved their peanuts

May be the survival instinct.