Feather

Feathers are special parts that cover birds and some ancient dinosaurs. They help birds fly, stay warm, and keep water out. The study of feathers is called plumology.

People have used feathers for many things for a long time. Feathers are soft and good at keeping heat, so they are used in bedding like pillows and blankets, as well as in winter clothing and sleeping bags. Feathers from geese and other large birds have also been used to make quill pens.

In the past, taking feathers from birds hurt some bird groups. Today, most feathers used for clothes and other things come from farms with chickens, geese, turkeys, pheasants, and ostriches. These feathers are often colored and shaped to look nice.

Etymology

The word "feather" comes from the Old English word "feþer". It is related to words in other languages. For example, in Dutch it is "veer" and in German it is "Feder". The Latin word for feather is "penna", and in Greek it is "pteron" or "pterux", both meaning 'wing'.

Early writing tools called quills were made from feathers. The word "pen" comes from the Latin word penna, which means feather. In French, the word plume can mean feather, quill, or pen.

Structures and characteristics

Feathers are special parts of birds. They grow from tiny spots in a bird's skin. Feathers are made of proteins. There are two main types of feathers: vaned feathers that cover the bird's body, and softer down feathers underneath.

Feathers help birds stay warm and dry. They are also important for flying. Some birds have special feathers on their heads, like crests. Feathers can be many colors and patterns. This helps birds hide or attract mates. Some feathers can make sounds, and others help keep birds dry.

Parasites

Feathers can sometimes have tiny creatures on them, like feather lice and feather mites. These lice usually stay on one kind of bird and can only move to new birds in a few ways, such as from parent birds to their chicks. Scientists find these lice interesting because they have changed over time with the birds they live on.

Birds keep their feathers clean by preening and bathing in water or dust. Some birds may use ants on their feathers to help keep pests away, but this is not proven.

Human usage

Bird feathers have been used for many useful things. They were once used to guide arrows and colorful feathers, like those from pheasants, decorated fishing lures. Feathers also help scientists identify birds, especially when birds hit airplanes.

Feathers have special meaning in many cultures. For example, eagle feathers are very important to Native Americans in the United States and First Nations peoples in Canada. In the past, feathers were used a lot in fashion, especially in hats. This led to the loss of many birds. This started efforts to protect birds and change fashion. Today, feathers are still used in special ways, like in hairstyles and traditional clothing.

Evolution

Main article: Origin of avian flight

Feathers are special coverings that help birds and some dinosaurs stay warm, look nice, and sometimes fly. Scientists used to think that flying was the main reason feathers evolved, but discoveries of feathered dinosaurs that couldn’t fly show that wasn’t the case. Feathers might have started as simple bristles that helped dinosaurs stay warm or sense their surroundings.

Feathers come in many types and have different jobs. Some help birds fly, while others keep them warm or make them look colorful to attract mates. Even dinosaurs that couldn’t fly had feathers, and these feathers might have helped them stay warm or look special to each other. Scientists study feathers to learn how birds evolved from dinosaurs and how these amazing structures developed over millions of years.

Functional considerations

The main reasons feathers exist are for warmth, flight, and looking nice. But new finds of feathered dinosaurs that couldn’t fly show that flight wasn’t the first reason feathers appeared. These dinosaurs had feathers that couldn’t help them fly, so scientists think feathers might have started to keep dinosaurs warm or to help them attract mates. Some think feathers began as simple bristles on a dinosaur’s face that helped it feel things around it.

Feathers are made from a material called keratin, which also makes up reptile scales. Scientists used to think feathers and scales were totally different, but now they see that feathers might have come from scales that changed shape over time. Smaller birds have more feathers than bigger ones, which helps them stay warm because they lose heat faster. The colors of feathers also evolved to help birds attract mates and hide from predators.

Molecular evolution

Scientists have found special genes that control how feathers grow. These genes can even turn scales into feather-like structures in some birds. Feathers and scales are both made from keratin, but scientists once thought only feathers had one kind of keratin. Now they know that even creatures like alligators have a type of feather keratin when they’re young, even though they grow scales as adults. This shows that feathers and scales share a common ancestor.

Feathered dinosaurs

Many dinosaurs had feathers on their arms that couldn’t help them fly. Some scientists think feathers first appeared to keep dinosaurs warm, and later helped small dinosaurs glide through the air. Others think feathers helped dinosaurs attract mates with their colors and patterns. Dinosaurs with feathers include Pedopenna daohugouensis and Dilong paradoxus, which lived millions of years before famous dinosaurs like Tyrannosaurus rex.

Most feathered dinosaurs were theropods, but some other dinosaurs also had feather-like structures. These structures might have been used to show off or attract mates. In 2014, a dinosaur called Kulindadromeus was found with structures that look like feathers. Scientists are still studying these to understand how they worked.

Since the 1990s, many feathered dinosaurs have been found in a group called Maniraptora, which includes the ancestors of birds. In 1998, a dinosaur called Caudipteryx zoui was found with feathers on its wings and tail, showing that feathers weren’t just for flying. Other dinosaurs like Sinornithosaurus millenii also had branched feathers.

The discovery of Anchiornis huxleyi in 2009 changed what we know about feathers. It lived earlier than Archaeopteryx and had modern-looking feathers, showing that feathers evolved before birds could fly. These feathers were found with older feathers, showing that simple bristles came before complex flight feathers.

Two small wings found in amber from 100 million years ago show that some bird-like dinosaurs had feathers. These wings were probably from enantiornithes, a group of early birds.

Evolutionary stages

Scientists have studied how feathers develop in baby birds and looked at fossils to figure out how feathers evolved. They broke it down into steps, starting from single bristles and ending with complex flight feathers. Some steps might just be how fossils look when they’re squashed, so scientists are still figuring this out.

In pterosaurs

Pterosaurs, which were flying reptiles, had fur-like structures called pycnofibres that covered their bodies. These looked different from bird feathers, but some scientists think they might be similar. A study in 2018 found that some pterosaurs had pycnofibres with features like bird feathers, which might mean feathers evolved in a common ancestor of pterosaurs and dinosaurs. However, other scientists think these structures might have evolved separately to look like feathers. Studies show that pycnofibres might have helped pterosaurs stay warm and fly better. Some scientists argue that these structures are not the same as feathers, but others believe they are closely related.