<P> The length of the silk fiber depends on how it has been prepared . Since the cocoon is made of one strand, if the cocoon is unwound carefully the fibers can be very long . </P> <P> Spider silk is the strongest natural fiber known . The strongest dragline silk is five times stronger than steel and three times tougher than Kevlar . It is also highly elastic, the silk of the ogre - faced spider can be stretched six times its original length without damage . As of 2005, there is no synthetic material in production that can match spider silk, but it is actively being sought by the U.S. military for such applications as body armour, parachutes and rope . Genetically engineered goats have been raised to produce spider silk in their milk at a cost of around $1,500 per gram . </P> <P> Wool is the fiber derived from the fur of animals of the Caprinae family, principally sheep, but the hair of certain species of other mammals such as goats, alpacas, and rabbits may also be called wool . </P> <P> Alpaca fiber is that of an alpaca . It is warmer than sheep's wool and lighter in weight . It is soft, fine, glossy, and luxurious . The thickness of quality fiber is between 12 - 29 micrometers . Most alpaca fiber is white, but it also comes in various shades of brown and black . </P>

Name the animal from which we get wool