Original sentence: lemmings look like a rat hamster
Edited sentence: It is unknown why lemming populations fluctuate with such variance roughly every four years, before plummeting to near extinction.Lemmings of northern Norway are one of the few vertebrates who reproduce so quickly that their population fluctuations are chaotic, rather than following linear growth to a carrying capacity or regular oscillations.The behavior of lemmings is much the same as that of many other rodents which have periodic population booms and then disperse in all directions, seeking the food and shelter that their natural habitat cannot provide.While for many years it was believed that the population of lemming predators changed with the population cycle, there is now some evidence to suggest that the predator's population may be more closely involved in changing the lemming population