Females are reddish-tan in colour, lack a cranial tuft, and have a crest of black or dark brown fur running from the crown to the nape of the neck.

They are reported to have an average weight of 7.5 kg (17 lb), although this is based on only a small number of wild individuals, and those in captivity appear to be larger.

[8] The species closely resembles the southern white-cheeked gibbon, but has slightly longer body hair and subtly different vocalisations.

However, samples of sweat taken from the axillae and chest possess lower levels of steroids in white-cheeked gibbons than in many other species of ape, suggesting that olfactory signals may be less important in these animals than in their relatives.

[6] The northern white-cheeked gibbon is arboreal in habits, and primarily herbivorous, feeding mainly on fruits, with some leaves, buds, and flowers.

These begin with the female making a series of 15 to 30 notes with an increasing pitch, followed by the male complex call with rapid changes of frequency modulation.

[6] In the closely related southern species, such duets are most common at dawn, and are apparently only made on sunny days.

[16] In captive studies, males and females that sing duets together the most frequently are the most likely to mate, indicating this may play a key role in pair-bonding.

In addition to the duet and solo great calls, males can also make booming sounds with their gular sacs, and short single notes.