After the extinction of the dinosaurs, the Earth was populated by other, gigantic animals: A 13-metre snake, a shark as big as a bus, a 20-ton rhinoceros and a sloth 200 times the size of sloths today. Although they dominate their ecosystems, giant animals are often more vulnerable than others. They are susceptible to climate change, shortages of food and competitors invading their territory. In fact, today’s last giants, are all in decline. Some of them are even threatened with imminent extinction.