Bornean and Sumatran orangutans differ a little in appearance and behavior. While both have shaggy reddish fur, Sumatran orangutans have longer facial hair. Sumatran orangutans are reported to have closer social bonds than their Bornean cousins. Bornean orangutans are more likely to descend from the trees to move around on the ground. Both species have experienced sharp population declines. A century ago there were probably more than 230,000 orangutans in total, but the Bornean orangutan is now estimated at about 104,700 based on updated geographic range (Endangered) and the Sumatran about 7,500 (Critically Endangered). A third species of orangutan was announced in November, 2017. With no more than 800 individuals, the Tapanuli orangutan is the most endangered of all great apes with no more than 800 individuals in existence (worldwildlife.org).