Extant megaherbivores are large megafaunaul herbivores that can exceed 1,000 kg (2,200 lb) in weight. They include elephants, rhinoceros, hippopotamus, and giraffes, and are the largest of the land animals. There are nine extant species of megaherbivores, distributed across Africa and Asia. The term "megaherbivore" was coined in 1988 by Owen-Smith to describe large mammals that performed similar ecological functions, such as habitat defoliation and extensive seed dispersal. Animals under are this group are K-selected, meaning they have high life expectancies, slow population growth, large offspring, lengthy pregnancies, and low mortality rates. They have selected slow reproduction to enhance their survival chances, and as a result, increase their lifespan. Their large size offers protection from predators, but at the same time, it decreases the degree at which they reproduce due to restricted food sources. On average, megaherbivores give birth to a single offspring every 1.3 to 4.5 years, depending on the species and also tend to have high lifespans, with giraffes living 25 years, rhinoceroses and hippopotamuses 40 years, and elephants 60 years.