The moment that black crested gibbons were playing on the ground was caught by the infrared camera in the Wuliangshan Nature Reserve of southwest China's Yunnan Province.
The video shows that one black crested gibbon was playing with another one with yellowish-brown fur on the ground. The latter was also holding a baby gibbon. Next to them, there were two black crested gibbons jumping among trees.
"There are totally three groups of black crested gibbons in the reserve. We set infrared cameras around all three groups, but only one of them was founded playing on the ground. This activity happened several times in multiple locations. Therefore, it is something meaningful and we can look more into it later," said Jiang Xuelong, researcher of the Kunming Institute of Zoology.
Under the first-class state protection, the black crested gibbon is also listed as critically endangered animal. Since they are arboreal animals, which means that they always sleep and eat on the trees, it is rare to find them on the ground.