I wish I had been able to get a better picture of the Siamangs. I can hear their call from our apartment, nearly 20 blocks away and I was thrilled when they started calling while I was at the Zoo. I raced over to watch this spectacle.

Described as a combination of a dog’s bark and a grouse’s hoot, siamangs sing (or call) to communicate between family groups. Singing communicates location between different family groups, establishes and maintains feeding area boundaries and is also for defensive posturing. It is believed that singing also helps form, maintain and further develop bonds between a mated pair.

Siamangs sing so loudly that it can be heard for up to 3 miles (4.8 km). To produce this loud call, siamangs have a hairless, reddish-brown or gray throat (laryngeal) pouch which acts as a resonator to enhance the carrying of their call. When not in use, the pouch is hidden under their long, shaggy, jet-black fur. When inflated, the pouch is about the size of a siamang’s head, and amplifies its hooting and barking to ear-splitting levels. Usually involving the adult pair, the male and female sing different but coordinated parts; songs have a definite beginning, middle and end. Each elaborate duet begins slowly, then accelerates in speed. A song lasts about 18 seconds and is repeated for about 15 minutes.

Hold your mouse over the musical note to hear a sample of the "song".