Felted
Felted is a term variously applied to hairy or otherwise filamentous material that is densely packed or tangled, forming felt or felt-like structures. Apart from fibres in felted fabric manufactured by humans, the term "felted" may apply to the condition of hair such as in the pathological condition known as felted hair, or it may apply to the tangled threads of the tissue of certain fungi, to matted fibres in animal connective tissue, or the felted coating of certain plants. To say that something is felted need not imply that any processes of matting, condensing and pressing fibres have been applied such the processes used in artificial production of felt fabric.
Zoology
Examples of the description of animal tissues as "felted" include classes of connective tissue such as the dermis which the classic Gray's Anatomy describes as: "felted connective tissue, with a varying amount of elastic fibers and numerous bloodvessels, lymphatics, and nerves." Also, in describing the external coat or tunica adventitia of an artery, Gray says: "...consists mainly of fine and closely felted bundles of white connective tissue..."[1] In such classes of connective tissue the felted structure is very important; it is versatile in resisting tearing by distributing localised stresses and it imparts strength together with shock absorption and elasticity in two or three dimensions at once, irrespective of the shape of the tissue.[2]
Other examples of felted material in animal structures include fibrous structures coating the integument of some insects. Usually such a felted coating is not living tissue, but consists of waxy fibres and is not particularly strong, but serves as protection from either excessive desiccation or moisture. It is particularly common in some families of the Hemiptera. In some species it occurs only as an outer coat of the immature insect, but in others, such as many of the Coccoidea, including the "Australian bug", Icerya purchasi and cochineal, Dactylopius species, it is secreted throughout the life of the insect and serves largely to protect the eggs rather than the insect.[3] In other species, such as many of the "woolly aphids", the Eriosomatinae, the most spectacular fluff is borne on the adult insect itself.[4]
The distinction between felted and other fibrous materials is not always sharp. For example, although truly felted hair on healthy mammals is unusual, many animals, especially in seasonally cold or wet climates or environments, often have a so-called undercoat of down hair plus awn hair that usually lies hidden beneath the outer coat of guard hairs, and may form a mat of likely felted wool. Such down hairs are as a rule finely woolly in texture and serve to trap insulating air and exclude water. In species such as musk oxen that live in seasonally frigid zones, the winter down hair is shed in clumps that can be collected for commercial use without the need for shearing.[5]
Many species of animals actively employ felting behaviour in preparing shelters for themselves or their young. It is not always possible to tell when such felting is purely incidental, but many species show behaviour patterns clearly adapted to the production of felted material suited to shelter and protection. The linings of nests of small rodents and small carnivores are common examples; some mice for example, such as ground-dwelling Mus species in parts of Africa build spherical nests of assorted fibres in burrows or under large flat objects. Some, such as various species of rabbit, in particular Sylvilagus species, use their own fur as a major component of their nesting material.[6] Small predatory mammals such the least weasel largely collect fur from their prey, or occupy prey nests ready lined; such fur commonly forms a felted nest lining.[7]
Birds vary enormously in the nests they make and the materials they use. Among those that use fibres and fibrous materials such as grass for nesting, many tend to weave the nests, but even woven nests such as those of weaver birds generally are lined with downy materials that largely become felted, both with each other and with the surrounding nest material. Accordingly birds such as sparrows that build large, twiggy nests lined with downy material. Many kinds of birds however do little weaving in building their nests, but instead construct their nests mainly of fibrous and downy materials such as fine wool, moss, lichen, spiders' nests, tufts of cotton, arachnoid fluff from plants, or bark scales, supported by twigs or the walls of burrows and the like, depending on the circumstances within which they nest. James Rennie remarked: "A circumstance also never neglected, is to bind the nest firmly into the forks of the bush where it is placed, by twining bands of moss, felted with wool, round all the contiguous branches, both below and at the sides. During the nesting season such birds commonly become such avid seekers of suitable materials, to the extent that down feathers or tufts of wool may be used as bait for trapping them. Birds that concentrate heavily on felted nests include goldfinches (Carduelis species), hummingbirds, and many species of small warbler-like birds.[8]
Various insects also create felted materials, generally forming part of the shelter for their young. Burying beetles are known for stripping the fur or feathers from the carcasses that they prepare for their young, and using the material to line and reinforce the crypt that they dig. [9] it is however unclear whether this habit is anything more than incidental, and also how relatively important it is in the different species of the genus. As long ago as the 19th century at least, Jean-Henri Fabre demonstrated that the species that he investigated most certainly did not depend on feathered or hairy food items, being quite able to utilise reptiles and amphibians and fishes.[10] However, there is no doubt about the use of felted fibre by various species of bees, in particular, those members of the Megachilidae that are known as carder bees build their nests mainly of plant fibre collected from arachnoid plants, though they also might add fibre from other sources, such as animal wool. The sheer amount of the material that they gather often is quite startling, and bearing in mind that the species of bees are not at all large.<ref name= "JHFBB">Fabre, Jean-Henri; Translated by Alexander Teixeira de Mattos; The Bramble-bees and others; Pub: Dodd, Mead, New York, 1915. Download from: http://archive.org/details/bramblebeesother00fabr /ref>
References
- ^ Gray, Henry. Anatomy of the Human Body. 20th ed. Revised by Lewis, Warren H. 1918. May be downloaded from http://archive.org/details/anatomyofhumanbo1918gray
- ^ Vogel, Steven. Cats' Paws and Catapults. Chapter 5. Penguin 1999. ISBN: 0-14-027733-1
- ^ Alan Weaving; Mike Picker; Griffiths, Charles Llewellyn (2003). Field Guide to Insects of South Africa. New Holland Publishers, Ltd. ISBN 1-86872-713-0.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ Costa, James T. The Other Insect Societies. Chapter 9. Publisher: Belknap Press 2006. ISBN: 978-0674021631
- ^ Feldhamer, George A. Mammalogy: Adaptation, Diversity, Ecology. Publisher: The Johns Hopkins University. ISBN: 978-0801886959
- ^ Long, Charles A. The Wild Mammals of Wisconsin (Faunistica). Pensoft Publishers 2008. ISBN: 978-9546423139
- ^ Jackson, Hartley H.T. et al. Mammals of Wisconsin. Publisher: University of Wisconsin 1961. ISBN: 978-0299021504
- ^ Rennie, James. Natural history of birds : their architecture habits and faculties. Chapter VIII. New York : Harper 1845 May be downloaded from: http://archive.org/details/naturalhistoryof00renn
- ^ Burton, Maurice; Burton, Robert. International Wildlife Encyclopedia. Publisher: Marshall Cavendish 2002. ISBN: 978-0761472698
- ^ Fabre, Jean-Henri. Tr. Teixeira de Mattos, Alexander. The glow-worm and other beetles Publisher: New York : Dodd, Mead and Company, 1919