Saturday, August 26, 2023

Bornean Orangutan

The Bornean orangutan is found only on the Island of Borneo, in the states of Sarawak and Sabah, part of the country of Malaysia and in the provinces of West, Central and East Kalimantan, part of the country of Indonesia.  
Borneo is the island with green on it. The green is portions of Borneo with orangutans. The northeastern portion is Malaysian Borneo and the rest is Indonesian Borneo. From Wikipedia. 
The Bornean orangutan is slightly larger than the Sumatran orangutan. It has gray skin, coarse and shaggy reddish fur. Fur does not cover its entire face, but it does have hair on the face, including a beard and mustache. It has fatty cheek pads known as flanges and a large throat sac. Males have: (a) larger flanges which are composed of muscle and mostly fat; females smaller flanges are composed mostly of muscle; (b) males have a more pronounced beard and mustache; and (c) the male's throat sac is considerably larger.  

Bornean orangutans are more solitary than Sumatran orangutans and spend less time in trees than their Sumatran relatives. They also have not been observed using tools, while their Sumatran relatives have. 

It is listed as Critically Endangered by the IUCN, like its Sumatran relative, but there are ten times more of them, roughly 105,000. 

We flew from Jakarta, Java, to Pangkalan Bun in Central Kalimantan near the south/central tip of Borneo. From there we were driven to Kumai where we got on a klotok, a wooden Indonesian two level boat with a shallow draft. The first day we sailed from Kumai, down the Kumai River to the Sokonyer River, where we entered Tanjung Puting NP, then up to Harapan Feeding Center, known as Camp 1. On the way we saw three wild orangutans along the side of the river. In this part of Borneo, orangutans that show up at the camps for food are not referred to as wild orangutans, even though they are wild, I guess because they are more habituated to humans. It was difficult to get good photos of them. 
Poor photo of a wild orangutan along the Sekonyer. 
At Camp 1 there was a platform where they deposited bananas at 4:00 p.m. for the orangutans. We saw an estimated 12 to 16 orangutans there, many of them mothers with babies and one large male that dominated the platform (eating more bananas than the others and the others showing fear of him and/or staying out of his space). 
Male (note large flanges) with young female.

Note large sac on throat. 

Female sitting on tree limb. 

Mother with baby on feeding deck.

Mother with baby in tree. 

We stayed that night at the Rimba Lodge, just off the Sekonyer River, about a quarter-mile beyond Camp 1. The next morning we sailed further up the Sekonyer River to Pondok Tanggui, also known as Camp 2, where we went to another feeding platform for the orangutans. We saw fewer orangutans there, about 7, dominated by a female. 
The dominant female hogging the bananas.

A brave young female dared to go on the platform and eat in the vicinity of the dominant female. 

A mother, with a small baby clinging to her back, very reluctantly and carefully came to the platform while holding on to a vine, with a foot, as an escape vehicle. She grabbed bananas which she held in her mouth and one hand and then swung away from the platform. 

Another mother, with a much large baby clinging to her back and another female approached the platform from the jungle. 

They eventually climbed the platform, cowering in a corner and warily ate bananas, while huddled together, under the gaze of the dominant female. 

On the way back out, on a wooden boardwalk, we encountered a young male named Atlas who blocked our way. We watched Atlas for quite a while and then carefully walked around him to get back to the Klotok. 

We traveled further upriver and got to Camp Leakey, also known as Camp 3. There we saw about 8 orangutans being fed at the wooden feeding platform. 
A dominant male with large flanges and large throat sac hogs the feeding platform. He eats more bananas than all of the other orangutans combined. 

A mother, with a clinging baby, walked right past us up to the platform. 

This mother and baby came to the platform from a tree. 
We traveled back to Rimba Lodge where we spent the night, then got up early the next morning and back out to to Kumai. We saw another 3 or 4 wild orangutans along the Sekonyer River from Camp Leakey on the way out. 
A wild orangutan in a tree, seen from the boat. 

Sunday, August 20, 2023

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.