This article is from
Creation 10(3):17–19, June 1988

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Feathers—an evolutionary enigma

by Jerry Bergman

Few masterpieces of paintings can compare with feathers in liveliness, softness, and harmony of colors. The black, the brown and grey pigments come from the bird’s blood; the red and yellow pigments, from its fat. The rainbow of colors shimmering on throat and tail feathers come not from pigments but reflective light. Microscopic ridges on the feathers break up the light that falls on them into the colors of the spectrum. So beautiful are feathers in pattern as well as color that men since ancient times have taken them from birds to adorn themselves.¹

Attempts to hypothesize the theory of the evolution of feathers have proved totally inadequate, producing only speculation. Most evolutionists suppose that feathers developed from the scales of reptiles, and many words have been penned speculating how this could have occurred. As far as physical evidence is concerned, not a shred exists. As Professor John Klotz notes:

“The origin of feathers is still a real problem. The feather cannot correspond to a whole scale but only to the outer half of the scale. The inner half or vascular core is believed to have atrophied. Any theory of the origin of feathers is hypothetical and can only be characterized as judicious speculation.”²

No clues of feather evolution have ever been found in the fossil record—thus no physical evidence exists of any change—which must exist if they evolved. For this reason, feather origin is considered an enigma.³ Literally millions of impressions of animals have been found frozen in stone, clay, peat, tar and amber, but no evidence of feather evolution.

The scales of dinosaurs and reptiles, feathers of birds, leaves of plants, and even the wings of insects trapped in amber are clearly detailed in the record of the rocks. Consistently found are scales that are fully scales, feathers that are fully feathers, and skin that is clearly skin. No transitional forms of a part feather/part scale have been uncovered.

Types of cover

All animals have a ‘covering’ to protect them from germs,cold or heat, and other adverse conditions. Four basic types of structures function as ‘covers’ to protect animals:

1. Skin, with or without hair, which can be extremely thin (such as that of many insects), of medium thickness (such as that covering humans), or thick, such as that covering cows and elephants (often called a hide).
2. Hair. Many animals also possess some type of hair in or over their skin or hide. Most mammals are abundantly covered with hair for warmth and insulation.
3. Scales, such as that found in reptiles, which range from the thin but strong scales covering the snake to the thick ironlike scales protecting the armadillo. Scales overlap like house shingles, and function in much the same way—they keep water out, keep in much heat, yet permit the animal to move.
4. Feathers are unique structures found only in birds. Feathers are considerably different from scales and skin, whether the skin is thin and hairy or thick and hairless. Feathers are not only “strikingly different from scales in their structure” but also in their development.² Feathers are well-designed complex structures, which are effective insulators, yet extremely light so the bird can fly. For strength and efficiency, man’s finest planes contain no part that can compare with them. Wing feathers are “one of the most beautifully designed structures in the world”.⁴

Flying and protection

Birds need feathers not only to fly, but to give the bird protection against the weather. Coated with a layer of oil, they protect the bird from water and heat loss. As Roger Peterson notes:

“The feather is a marvel of natural engineering. It is at once extremely light and structurally strong, much more versatile than stretched skin on which a bat supports itself in flight, or the rigid structure of an aircraft’s wings — and far more readily repaired or replaced when damaged … Though nearly weightless it has strength. The stiff shaft of the quill provides rigidity when support is needed, yet it is supple towards its tip, when flexibility is required for split second aerial maneuvering. Feel the sleekness of the web, soft yet firm. Separate the barbs; zipper them together again by running them through the fingertips as a bird would preen with its bill. The intricacy of the design that allows this can be appreciated by putting the feather under a microscope.”⁵

Main parts of feathers

Many birds boast many thousands of feathers; a Plymouth rock hen has an estimated 8,000, a whistling swan, 25,000. Feathers and scales are outgrowths of the skin, and are as devoid of feeling as our hair or nails (that is why no pain is registered when hair is cut or nails trimmed). The main parts of the feather are the long shaft (usually hollow, always strong) and the web which flares out from the shaft. The web is held tightly together by ‘hooklets’ which attach to the next web, much like the fastener Velcro.

If the hooklets are lacking, such as in the plumes of the ostrich, the bird cannot fly. Hooklets will separate, but easily reattach when the bird preens its feathers (ruffled feathers usually prompt preening). These branches form a web so dense that when the bird flies very little air seeps through them.

The feather web must be strong, yet flexible, so it will not break in the wind. Such design enables birds to ‘ride air currents’ more gracefully than the best glider human engineers have designed.

The shaft of most feathers has two parts, a hollow stiff quill, called the rachis, a solid but flexible support for the web or vane. The shaft, similar to a tree trunk, has branches called barbs. Each parallel barb, which slants diagonally from the shaft, has numerous smaller side branches or barbules that overlap those of the neighboring barbs in a herring-bone pattern which appears as a miniature replica of the whole feather.⁵ These in turn have barbicles. The feather is not similar to skin or scales, and is infinitely more complex than hair.

Feathers vary greatly in structure. And none of these variations is in the direction of scales, as would be expected from evolutionary theory. One variation is what is known as down, where little or no shaft is present, and the barbs interlock less often than in non-down feathers. In other types of feathers, such as the bristles around the mouth of a flycatcher, the vane may be nearly or totally absent. In yet others, it may be solidified, as in the penguin.

Fast and slow feathers

The two basic types of flight feathers are called fast and slow. The strong and trim, or fast, feathers serve birds such as pigeons, hawks and those that must travel very fast. The slow type, a soft and loose-edged structure, serve birds such as owls, which fly and soar slower, but whose flight must be quieter than that provided by fast feathers (more important to an owl than speed).

Feathers, hair, fingernails, and scales form in pits underneath the skin. Each pit is supplied with blood to nourish the growing feather.

Most birds ‘shed’ or lose their feathers at regular intervals, a process called moulting. Special muscles enable them to control movement of their feathers. This system aids flying and protection. Some birds fluff themselves out for reasons such as to give the appearance of more mass to frighten their enemies, keep them warmer, and attract birds during mating. The famous spread of the peacock is a wonderful example of the level of control some birds have over their feathers.

Ideas on feather origin

Air spaces between the feathers serve to insulate the small body, a function so important that many evolutionists assume that feathers originated primarily for insulation, and only later facilitated flight.⁶ Tucker hypothesizes that the first step in bird evolution was not the development of the ability to exploit the air, but of a light and effective ‘thermostat mechanism’ to maintain constant temperature—and part of this system was the feather. This conjecture, Dewar notes, is tenuous because of the assumption that:

“… a cold-blooded creature … became warm-blooded may be met by suggesting that the transformation took place in the tropics where the temperature is fairly constant and about that of blood-heat. But even so there remains the difficulty of the origin of a most complicated mechanism [the feather] for preventing the individuals in question from becoming overheated when pursuing their quarry. In the case of birds the heat-regulating mechanism is not fully understood. The feathering prevents undue dissipation of the heat generated by the chemical processes of the body. The spacious air sacs, which are organs peculiar to birds, probably assist in the dissipation of heat generated during periods of great activity. But these alone would not suffice to maintain a constant temperature. There seems to be a special nervous mechanism which controls the oxidation of the tissues and regulates the blood supply to every organ.”⁷

“Previous theories relating to the origin of feathers and flight or to heat conservation are considered to be inadequate.”⁸

Early evolution textbooks, such as that of Osborn,⁹ showed a set of transformation or ‘intermediate feather types’ which scientists thought for sure they would surely find. So far, not one of these hypothetical transitional types has been found. The evolutionary enigma of feathers remains.