five species at high risk of extinction Ecosystems change over time and species evolve or do not survive, although the hand of man seems to accelerate some processes. This is a list of five animal species, from least to highest risk of extinction, included in the red list of the International Union for Conservation of Nature (IUCN), an organization formed by international public institutions and civil society that quantifies and alerts on the animal demography and its evolution. Giraffes: The giraffes or Giraffa camelopardalis is the tallest animal in the world, but its ability to see the dangers from privileged heights seems not to be enough to stop the demographic decline experienced by its species. In only three generations, its population has been reduced by almost 40% and has risen from the category of "low concern" to "vulnerable" in the red list of species. Cheetahs: The cheetahs or Acinonyx jubatus are animals similar to leopards or pumas, wh...