Bornean orang utan 'Natalia' climbing carefully

16-month old infant, looking for willow buds. Large orang island, Paignton, 18th April 2015.

The babies both look very thin and scrawny to me. You can see ribs and even loose skin on the belly, in this shot. I don't remember other baby Orangs I've seen looking like this. I wonder if they are having to compete with their own mothers for food? (In the early days of breeding at e.g. ZSL they tried to remove the babies e.g. Bulu, at 18 months old for that reason)

I have photos of Tatau at this age where she appears more substantial and doesn't have a wizened little face like Natalia's. They both have Demo's genes and he was long and lean. Mali is also like that but Chinta has the London orang shape, short and wide.

The orangs are not showered with food during the day like the gorillas are and are usually foraging when outside. Food appears scarce in the showden. Presumably they get hearty meals in the morning and evening instead. Whether they share them with their daughters is another matter.

I recently watched a TV series about Sepilok and the young orphans there looked quite stout in comparison.

I don't think there is a problem here. At this age they should still be nursing as well as taking some solid food, although I didn't notice this while I was watching. There is a feed scattered on the islands before the orangs come out and they may get more during the day too.
Natalia was certainly eating vegetation on the large island and she was also having treats from the log feeder with Chinta (as shown in a separate photo here). I think these babies look healthy and they are both very active, as the photos show; they do not sit on the ground with their mothers as zoo orangs tended to do years ago. Some of the footage from rehab orangs shows them doing much the same, at least when newly arrived - when they also may have pot bellies from poor diets as household pets.
I will check my photos for shots of Iznee and Latifah at similar ages, as they were also notably active and should make an interesting comparison.

Alan