How many gibbons would it take to defeat a human?

Gibbons weigh about 5.7 Kg while the average human weighs 62 Kg This means that it would take 10.877193 Gibbons to weigh the same or 11 to have and advantage. read more

There is an intrinsic flaw in your question, unfortunately. As in many other questions flooding Quora about 'How many Animal X would it take to kill a human' the major flaw lies in a fundamental misunderstanding of animal behaviour. read more

Gibbons are territorial and a family unit will defend areas between 50 and 100 acres (Geissmann Gibbon Research Lab: Social Behavior). They travel through their territory at about 1 mile per day. Their territory is defended through vocalizations from the center of the territory and calls from the boundaries. read more