The biggest differences between a sloth and a koala are range, size, and speed. The koala lives exclusively in Australia, but the sloth lives in many countries in Central America and South America. Koalas are bigger than sloths, too. In fact, they can stand an entire head larger than the average sloth. Also, koalas are much faster than sloths, reaching speeds of 15-20mph over short distances when the need arises.