The Lar Gibbon has a size of 42 to 58 centimeters with a weight between 4.5 and 7.5 kilograms. This species has a petite appearance, with very long arms and possesses no tail. Its fur has a variable color. It can be black, dark brown, light brown and sand colored. The hands and feet and the wreath of fur around the eyes, nose and mouth turn white. If the Lar Gibbon shows its teeth to you, you will see large dagger-like canines in both the upper jaw and lower jaw.
The Lar Gibbon usually lives in pairs. They therefore form a close family. Every 3 years, the female usually gives birth to a young. Young does not reach adulthood until it is 4 to 5 years old, but it can live with the family for some time after that. Because of this, it is common to see a pair with 2 or even 3 young.
Every morning, just before or after sunrise, the Lar Gibbons sing a duet. They do this to defend their territory, to seduce another and to strengthen the pair bond.
The Lar Gibbon has a diversity of enemies such as Nebula leopards, Marble cats, Asian gold cats, Bengal tigers, Leopards, Pythons and Eagles.