(Found) Search for Title

[Sir Branimal]

Looking for the title of a novel I read about 30 years ago. It was about two neighboring planets on which intelligent life evolves. I remember one planet evolving from reptilian creatures and the other was mammalian I think. The story covers the time they were both primitive, through the evolution process, into their mutual development into intelligent sentient beings. They eventually contact each other. By the end, both worlds launch nuclear attacks on the other, wiping out all intelligent life.

 

[Victoria Silverwolf]

This sounds like First Cycle (1982) by H. Beam Piper and Michael Kurland. (Kurland completed what Piper left unfinished at the time at his death.)

Title: First Cycle

www.isfdb.org

Synopsis from the back cover:

"In a galaxy very far away, two planets were born in a fiery collision and began to circle a yellow sun. One was watery while the other was hot and arid, but life was tenacious, and managed to develop slowly on both worlds. On the watery planet, fish crawled from the sea and became amphibians, then grew greenish fur to protect them from the cold, and finally walked upright and bore patches of green hair only on their heads. On the arid planet, creatures like large slugs developed bones from their cartilage, crept through the desert as lizards, and finally evolved into red-furred creatures with cat-like faces and monkey's limbs. On both planets the natives grew more intelligent, learned about trade and war, and sang songs celebrating their exploits. The centuries went by, and eventually it was inevitable that two civilizations living so close to each other would find a way to meet. the history of all civilizations could have predicted that their meeting would not be peaceable..."

 

[Sir Branimal]

You are awesome, this is what I was looking for, thank you!