The thousands of bone remains unearthed correspond mainly to carnivorous animals of the Tertiary Age. There is a very wide wildlife set consisting of giant tortoises, mastodons and giant giraffes with complete specimens, and more than eleven species of carnivores, birds and insectivores. According to the scientists who work every summer in the Cerro de los Batallones, these accumulations of bone remains are due to the existence of natural cavities in the subsoil, which acted as real natural traps: animals that dared to enter them, almost all carnivores, were trapped without being able to go outside. The site was discovered coincidentally in 1991. Since 2000 the Community of Madrid, in collaboration with the Museum of Natural Sciences of the Higher Council of Scientific Research, carries out an intense scientific work in this place.