As Chimpanzees Grow, So Does Yawn Contagion (IMAGE)
Caption
The ability to empathize may influence chimpanzees' susceptibility to contagious yawning.
Credit
Elainie Madsen
Usage Restrictions
All figures and photographic images will be published under a Creative Commons Attribution License (CCAL), which allows them to be freely used, distributed, and built upon as long as proper attribution is given.
License
Licensed content