Siamangs are the largest gibbons and are found in Sumatra and the Malay Peninsula. Palm oil expansion has destroyed much of their lowland rainforest habitat, and the species faces declining populations in areas with high agricultural conversion rates.
Siamangs in fragmented forest patches face isolation of family groups, reduced access to fruit and leaves in degraded habitat, and increased exposure to human activity. Infants separated from parents by habitat disturbance cannot survive independently. The species dependence on large home ranges in intact forest makes them particularly vulnerable to small-scale fragmentation that other primates may tolerate. Welfare science from captive populations informs understanding of enrichment needs and social requirements.