50 years ago, small centre for animals was set up in hills of Santa Clarita Valley, outside Los Angeles, today globally recognized institutions look after rare, endangered gibbons

In between morning feedings, the gibbons begin to sing — loudly. Ranging from the sound of emergency sirens and birds screeching to low grunts and guttural hoots, their vocalisations reverberate from a sanctuary in the hot, dry hills of the Santa Clarita Valley, north of Los Angeles. Over the past 50 years, the Gibbon Conservation Centre has transformed from housing a small assortment of animals to becoming a globally recognised institution dedicated solely to the care and well-being of gibbons. Known for their signature singing, they are among the rarest and most critically endangered primates on Earth.

Today the centre cares for some 40 gibbons across five species. Their singing can sometimes be heard a mile away by the few neighbours in the sparsely inhabited outskirts of Santa Clarita.