#Downy feathers skin#

They’re so synonymous with flight that some sources say that filoplumes don’t exist on penguins, ostriches, and other flightless birds.

These sit at the base of flight feathers and supposedly sense organs, which tell flying birds when their plumes have become displaced. These are tiny structures, less than a centimeter long, with a naked shaft that ends in a splay of fine filaments. Williams also found a third category of feather-filoplumes-that no one had mentioned at all. The plumules, which are far more numerous, were first mentioned a century ago and have been almost entirely ignored since then. Despite several attempts to model the insulating powers of penguin skin, every study has ascribed those powers wholly to the afterfeathers. Williams found plenty of afterfeathers on her birds, but also four times as many plumules-a separate type of downy feather that attaches directly to the skin. Many studies assume that emperor penguins insulate themselves from the bitter cold of Antarctica’s waters using afterfeathers-small downy plumes that are attached to their main feathers. Second, Williams found certain types of feathers that she wasn’t expecting. The white-throated dipper, a small Eurasian bird that forages in cold mountain streams, has plumage that’s six times more dense. That’s nowhere near the record for birds. By carefully plucking, counting, and describing the feathers on these specimens, Williams and her colleagues found several surprises.įirst, these birds had a maximum of nine feathers per square centimere-a lower density than any of the earlier reports suggested. The bodies in question belonged to emperors that had died of natural causes in 20, and had been stored in a freezer ever since. “Since we had access to several penguin bodies, we decided to find out for ourselves,” says Williams. They might as well have come up with random numbers. Various scientific papers claimed that penguins had anywhere from 11 to 46 feathers per square centimetre, and none of them-none-described any methods or cited any sources behind these estimates. When Cassondra Williams from University of California, Irvine, first started looking into penguin feathers, she was shocked to see how many unsubstantiated statements there were, and not just on websites. This “fact” crops up on Wikipedia and a host of other websites, and seems to trace to a statement made in a 2004 National Geographic news story.

#Downy feathers skin#

Emperor penguins reputedly have the highest feather density of any bird, with around 100 feathers per square inch of skin (15 per square centimeter).