There are animals that develop substances poisonous to other living things that used as part of their strategies of defense or attack. These include snake venom injectors have teeth, in many cases fatal to other animals and man, bees and wasps have a sting which injected with toxins in the body of their victims; scorpions, certain lines and weeverfish , which are equipped with poisonous spines in different parts of your body. The chemical nature of poisons is varied, and according to it there are two major groups: the neurotoxic (acting on the nerve centers, paralyzed) and haemotoxic (which centralize its activities in the blood and cause bleeding).
Certain poisons animals are important in medicine. Since they are made some analgesics used in the treatment of cancer or arthritis, and some hemophiliacs who receive clotting.
Spiders defensive system used as a pair of poison claws, while other animals attack them with their tusks, horns or mandibles prominent.