We all have them: Days when we just want to take it down a notch, even as others around us burst with energy.
David, alpha-male chimpanzee at Fongoli in Senegal, had a morning like that recently. While other males vocalized (pant-hooted) with gusto, a perfectly hale and hearty David ... just couldn't be bothered, as this video bit shows.
The clip was posted by biological anthropologist Jill Pruetz. Pruetz's ground-breaking discoveries at Fongoli include chimpanzees wielding spears as they hunt smaller primates.
You can keep up with more of what Barbara is thinking on Twitter: @bjkingape