Sumatran Orangutan

The Sumatran orangutan is one of three species of orangutan. The other two are the Bornean orangutan (found in Borneo) and the Tapanuli orangutan (found in Sumatra in the area of South Tapanuli, further south in Sumatra than where the Sumatran orangutan is found). 

This is the first orangutan we saw, a female. 

Male Sumatran orangutans can grow to be 5 feet, 6 inches tall and 200 pounds. Females can grow to be 3 feet tall and 99 pounds. Compared to Bornean orangutans, ,the Sumatran orangutans are thinner, have longer faces, have longer hair and the hair is paler red. 

These were the second and third orangutans we saw, a mother and child. 

In 2016 it was estimated that there were 13,846 Sumatran orangutans in the wild. 95% of them are found in the Leuser Ecosystem, which includes Gunung Leuser NP, which we visited. 82.5% are found in the Aceh Province, at the northern tip of Sumatra. We visited North Sumatra Province, which is further south, near Bukit Lawang. The Sumatran orangutan is deemed Critically Endangered by the IUCN. 

They are frugivores, favoring fruits with a large seed surrounded by flesh, such as durian, lychee, jackfruit, breadfruit and fig. They also eat lots of insects, such as ants and termites. 

They have five stages of life: (1) Infancy is from birth to 2.5 years, the infant is always carried by the mother during travel and is highly depended on the mother for food; (2) Juvenile-hood is between 2.5 and 5 years, the juvenile is still mainly carried by its mother but ventures to play with peers and short trips within the sight of its mother, toward the end of this stage the juvenile stops sleeping in its mother's nest and makes its own nest nearby; (3) Adolescence is from 5 to 8 years, a lighter face becomes completely dark, the adolescent develops relationships with peers in groups, but still has constant contact with its mother; (4) at 8 years females are adults and start to have their own babies, but males enter sub-adulthood, until about age 13 to 15, they begin to develop cheek flanges, they start to develop beards, the hair around the face shortens, the face flattens and they reach sexual maturity, but are still socially undeveloped; and (5) males reach adulthood, have a fully grown beard, fully developed cheek callosities, long hair, fully developed social maturity and begin traveling alone. Females live 44 to 53 years and give birth up to age 53; males live 47 to 58 years. 

We saw 8 Sumatran orangutans. First we saw a single female outside Bukit Lawang and before Gunung Leuser NP. It was in an area of planted palm trees where it was easy to see and get good photos. 

Next we saw a mother and baby. I'm guessing the baby was 2.5 to 5 years old, or maybe even a little older. This was also before the NP and just after a more remote group of guest houses. The trees were thicker, but not as thick as we would find in the NP. 

I was very close to the mother here and our ranger waved for me to move away. I had stationed myself and she kept moving toward me. 

The other five orangutans we saw were in the NP where the forest was very thick and the canopy made it very difficult to see the orangutans, let alone get good photos of them, particularly with my camera that had lost the ability to automatic focus. We saw two of those five on two occasions. Only only got one good photo of those five, a relatively young male. We got relatively good views of the others, but they were usually moving around, in and out of good visibility. 

Even pretty close, the leaves would obscure the views, even more so the higher up in the canopy. 

This is the one good photo I got in the NP.

This is a bad photo of another orangutan, a female, in the NP.