The modern day replicas are basically made of durable plastic covered with leather. This ensures lightweight, long-lasting and cost-effective bows that resemble the original to the slightest detail so you cannot distinguish a plastic one from a natural one. There are, however, some traditional recurve bows made exactly to the standards of ancient archer nations. These bows are made of fish bones, bull horns, cattle bones and tendons and, of course, fine wood. The parts are attached by natural adhesives such as collagens extracted from fish or cattle. The result is a more expensive, less durable but naturally much more stylish bow than a plastic one.
It is interesting to note that the huge and awkward longbows used in Europe during the medieval era were in all respect inferior to the portable, precise and strong recurve bows of Asia, especially considering that the bows used by nomadic people could be used by children too, as opposed to western bows.