baby siamang?
Apparently siamangs exist and the El Paso zoo has inherited a baby one:
https://youtu.be/A2-6gPPN47A
The siamang is distinctive for two reasons. The first is that two digits on each foot are partially joined by a membrane—hence the name "[syndactylus](https://en.wikipedia.org/wiki/Syndactyly)", from the [Ancient Greek](https://en.wikipedia.org/wiki/Ancient_Greek) _sun-_, "united" + _daktulos_, "finger". The second is the large [gular sac](https://en.wikipedia.org/wiki/Gular_sac) (found in both males and females of the species), which is a throat pouch that can be inflated to the size of the siamang's head, allowing it to make loud, resonating calls or songs.