‘Hylobates muelleri‘ is known in English as ‘Mueller’s Bornean Gibbon’. But I much prefer the Indonesian name ‘Owa wa‘, which is a near-exact transcription of this gibbon’s distinctive call.
This primate is endemic to the island of Borneo. It’s classed as ‘endangered’ – mostly because of the continuing loss of its forest habitat.
I saw this one (an adult female) this morning at the Kebun Raya Balikpapan. She was a little distant, and I had to photograph her through the branches and foliage of another tree. Hopefully there’ll be more opportunities to see, hear and photograph Owa wa before the year is out.