The leatherback sea turtle (Demochelys coriacea) is the earth's biggest turtle and has the largest range of any species, swimming all over the globe from the tropics to the sub-polar regions. When it comes time to dig a nest and lay its eggs, it crawls out onto sandy sub-tropical beaches the world over. The leatherback is also critically endangered. According to the IUCN, in 1982 there were around 115,000 adult female leatherback turtles in the world; just 14 years later, there were only 20,000 to 30,000—and the population has continued to plummet. The leatherback's problems include theft of its eggs by humans, illegal hunting and nesting-habitat loss due to beach development, and the erosion of beaches due to global climate change. In addition, leatherbacks sometimes die after ingesting plastic debris they find floating in the ocean, which they mistake for food such as jellyfish.