Tapeworm head, light micrograph. Adult tapeworms (Tinea sp.) are parasites that inhabit the intestines of animals and humans. Different species of tapeworms have different animals as their intermediate and final hosts. The hooks and suckers (round) at the tip of the scolex (head) are used to anchor the worms to their host's intestinal lining. They do not possess a digestive tract and so absorb nutrients from the half-digested food of the host through their skin.