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Sumatran Rhinoceros (Dicerorhinus sumatrensis)

This is the most diminutive of all rhino species (3-1/2 feet tall and a mere 1 ton), and the only one with two horns, and like most of its cousins, it is critically endangered. Two subspecies are barely holding on in Western and Eastern Sumatra, while a third is thought to have gone extinct, according to WWF. Sumatran Rhino Rescue is working to collect the 80 remaining, struggling, individuals from the wild and bring them to sanctuaries where they are safe from poaching and can be bred—efforts which would benefit all rhino species. Find out 15 reasons why rhinos are worthy of your attention.