Heavy users of Twitter or Facebook who constantly update their status have a counterpart in the animal kingdom...vultures. These birds can quickly change their skin color to let friends and enemies know how they're doing.
Lots of animals have the ability to change their skin color, thanks to special cells that quickly redistribute the pigments in skin cells. Fish and reptiles are most commonly seen to have this ability, but some mammals and birds are able to do it as well, as long as they can display some bare skin that isn't covered in fur or feathers. (Which might suggest humans really missed out by not developing this ability, considering we're practically all bare skin.) But vultures are one of the few creatures that we know uses this ability as a form of communication.
Dr. Andrew Bamford of Nottingham University explains this phenomenon:
"Vultures have un-feathered sections of skin on their heads which can become bright red when blood flow is increased, a technique known as flushing. The advantage in using their bare skin as a signal is that colour changes can occur more rapidly than in feathers or fur, provide up-to-date information on status."
Bamford and his team studied a bunch of Lappet-faced vultures in northern Namibia. They placed food at a number of known vulture hangouts, then examined how the vultures interacted when competing for the food. They discovered the adults that flushed their heads to display dominance won the majority of the food over pale adults and vulture young, and the pale adults had no advantage whatsoever over the juveniles. There was even a little nuance to the flushes - blue-throated vultures regularly got the better of their red-throated counterparts.
Of course, as Dr. Bamford unintentionally points out, there is one rather big difference between human and vulture status updates - unlike humans, it seems as though other vultures actually consider these updates important:
"Our study has shown colouration correlates with the outcome of interactions in gatherings of lappet-faced vultures. "Previously interaction was thought to depend on aggressive behavior, but face flushing status plays an important part in the initiation of, and response to, interaction from other vultures."