Lar Gibbon, ThailandLar gibbons, also known as white-handed gibbons, in Thailand’s Kaeng Krachan National Park are famous for their haunting, echoing duets. Mated pairs sing complex, synchronized calls at dawn to defend territory and strengthen their bond. Nikon D500 with Nikkor 200-400mm lens (at 280mm) ISO 800, f/4 at 1/160th of a second.