"This means we can use a noninvasive method to develop the next generation of brain-computer interface machines," Contreras-Vidal says.

Chuang Chuang weighs 150 kilos (330 pounds), while his partner Lin Hui is a lithe 115 kilos (253 pounds), said Kannika Nimtragol, a veterinarian at the Chiang Mai zoo in northern Thailand.