"Survival mechanism" refers to any instinctive or learned behavior in living organisms that helps them adapt and endure in challenging or threatening situations. It is a natural response or strategy that ensures their continued existence and safety.
Today we know that love is, in actuality, the pinnacle of evolution, the most compelling survival mechanism of the human species. (coloradocouples.com)
This state is extremely stressful for the body and stimulates survival mechanisms which include slowing of the metabolism and a loss of interest in sex (not as important as food for survival). (drjockers.com)