Baby Bornean orang comparison Natalia and Iznee

'Natalia' at Paignton, 18th April 2015 aged 16 months and 'Iznee' at Chester, 11th June 2011 aged 25 months. To illustrate the points raised by a previous image of 'Natalia'.
The skin on the torso of a young orang is loose and flexible: it becomes ridged when the back is flexed, but these ridges do not show the ribcage in healthy individuals. 'Iznee's' shorter hair shows clearly that he is quite healthy and so, in my opinion is 'Natalia', whose skin is not ridged in this image.

Alan

i know the Chester baby is nine months older ( in the photo) and male, and I take your points above. He's how I expect a youngster to look though, whereas the Paignton baby's arms and legs are skinnier. Not suggesting they aren't healthy, but still feel they could be a tad undernourished?

There's a photo of Natalia on the zoo's facebook page. It was posted on 20 March but the date on which it was taken is not shown - the lack of leaves on the tree is the only clue. When I see the babies close up in the showden after watching them through binoculars or a camera, I'm always surprised at how small they really are, but Natalia does look very delicate in this FB photo.

I took several shots of 'Natalia' in front of 'Chinta' in the same place and very similar poses to that photo on Facebook. I didn't post them because 'Chinta' was mostly hidden and there were some unsightly shadows from the twigs*. I chose to show the ones where she was climbing independently and quite expertly for the orang equivalent of a human toddler.
As far as I can tell, she is developing well and the main reason that she is small is that orangs develop very slowly, even compared to the other anthropoid apes. As Pertinax has pointed out, 'Iznee' is larger in these photos, mainly because he is rather older, perhaps because he's male and also, perhaps, because 'Sarikei' is a larger female and a more experienced mother. 'Natalia' may be a little small for her age, but she seems active and well co-ordinated, with a healthy coat, and she watches 'Chinta' feeding with great interest and copies her.
I am sure that the keepers are watching 'Tatau' and 'Natalia' carefully, if they feel that any supplementary feeding is necessary they will work out how to do it.

Alan

* Correction - except for this one.