Robin on Instagram: "Siamang gibbons live in the rainforests of Sumatra and the Malay Peninsula. They are the largest of all gibbons and the only ones with a fully inflatable throat pouch. This adaptation allows their calls to carry across large distances, making sound their primary way of communicating and spacing themselves in the forest. Their vocalizations can exceed 100 decibels, which is why they are often heard long before they are seen. #sonyalpha #sonya1ii #documentary #nature #siamangg