r/K selection theory
![A North Atlantic right whale with solitary calf. Whale reproduction follows a K-selection strategy, with few offspring, long gestation, long parental care, and a long period until sexual maturity.](/Images/godic/202502/08/Eubalaena_glacialis_with_calf1821.jpg")
![A litter of rats with their mother. The reproduction of rats follows an r-selection strategy, with many offspring, short gestation, less parental care, and a short time until sexual maturity.](/Images/godic/202502/08/Mouse_litter1821.jpg")
In ecology, r/K selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus upon either increased quantity of offspring at the expense of individual parental investment in r-strategists, or reduced quantity of offspring with a corresponding increased parental investment in K-strategists, varies widely, seemingly to promote success in particular environments.