The r strategists live in unstable and unpredictable environments hence they produce many offspring while the K strategists live in more stable and predictable environments hence they make few offsprings. This is the key difference between r strategist and K strategist. Bacteria, insects and corals are few examples of r strategists while human, primates, and elephants are few examples of K strategists. One other notable difference between r strategist and K strategist is their sizes. The r strategist is smaller in size while the K strategist is larger. Also, the r strategist shows early maturity and shorter lifespan while the K strategist shows late maturity and longer lifespan.