A pair of resident gibbons at Denver Zoo in Colorado showed off their vocal prowess with a duet, video shared on January 7 shows.
The clip shows gibbons Leo and Lola hanging from nets in their enclosure as they vocalize.
Gibbons mark their territory with loud songs that can be heard throughout the zoo and its environs, the zoo said.
Siamang gibbons are the loudest land mammals, and can be heard up to two miles away. Credit: Denver Zoo via Storyful