Emperor penguins apparently have the best feather density of any hen, with round 100 feathers per sq. inch of pores and skin (15 per sq. centimeter). This “reality” crops up on Wikipedia and a number of different web sites, and appears to hint to an announcement made in a 2004 Nationwide Geographic information story.
It’s not true.
When Cassondra Williams from College of California, Irvine, first began wanting into penguin feathers, she was shocked to see what number of unsubstantiated statements there have been, and never simply on web sites. Varied scientific papers claimed that penguins had wherever from 11 to 46 feathers per sq. centimetre, and none of them—none—described any strategies or cited any sources behind these estimates. They could as effectively have give you random numbers.
“Since we had entry to a number of penguin our bodies, we determined to search out out for ourselves,” says Williams. The our bodies in query belonged to emperors that had died of pure causes in 2001 and 2005, and had been saved in a freezer ever since. By fastidiously plucking, counting, and describing the feathers on these specimens, Williams and her colleagues discovered a number of surprises.
First, these birds had a most of 9 feathers per sq. centimere—a decrease density than any of the sooner studies prompt. That’s nowhere close to the document for birds. The white-throated dipper, a small Eurasian hen that forages in chilly mountain streams, has plumage that’s six instances extra dense.
Second, Williams discovered sure kinds of feathers that she wasn’t anticipating. Many research assume that emperor penguins insulate themselves from the bitter chilly of Antarctica’s waters utilizing afterfeathers—small downy plumes which can be hooked up to their most important feathers. Williams discovered loads of afterfeathers on her birds, but additionally 4 instances as many plumules—a separate kind of downy feather that attaches on to the pores and skin.
That is reasonably ironic. Regardless of a number of makes an attempt to mannequin the insulating powers of penguin pores and skin, each research has ascribed these powers wholly to the afterfeathers. The plumules, that are way more quite a few, had been first talked about a century in the past and have been nearly solely ignored since then.
Williams additionally discovered a 3rd class of feather—filoplumes—that nobody had talked about in any respect. These are tiny buildings, lower than a centimeter lengthy, with a unadorned shaft that ends in a splay of nice filaments. These sit on the base of flight feathers and supposedly sense organs, which inform flying birds when their plumes have grow to be displaced. They’re so synonymous with flight that some sources say that filoplumes don’t exist on penguins, ostriches, and different flightless birds. Clearly, that’s unsuitable.
“We had been a bit of stunned to see filoplumes on the penguin physique,” says Williams. “However serious about it, it makes as a lot sense for penguins to preen physique feathers to take care of a slick, waterproof exterior, because it does for flying birds to preen their wing feathers to cut back drag in flight.”
Though Williams solely checked out 4 penguins, she says that the sample and density of feathers isn’t more likely to fluctuate a lot throughout the inhabitants. “All of them face the identical harsh Antarctic winters and dive in freezing waters, so the insulation necessities are the identical,” she says. “After all we might have most well-liked a bigger pattern dimension, however it is extremely troublesome to acquire absolutely preserved penguin carcasses.”
“These outcomes definitely have implications for penguin conservation and well being,” provides Williams. “If these penguins had been caught in an oil spill, it will be nearly not possible to wash the feathers. The “fluffiness” of the downy feathers is a key element of the insulation properties and oily downy feathers would destroy this element.”
There are sensible functions too. A number of scientists need to penguin feathers as inspiration for underwater fits—precise penguin fits—which can be higher at retaining warmth and repelling water.