Threatened arthropods United States, and IUCN Red List for international purposes. Only a tiny fraction of the planet's endangered arthropods are formally recognized as such, as no one has ever evaluated the conservation status of the vast majority of arthropod species. It is difficult to estimate the total number of endangered arthropod species, since many of the taxa themselves have not been recorded. For example, in North America the estimated number of insect species exceeds 163,000, of which only about two thirds are taxonomically known. An even greater discovery awaiting, over 72 percent of North American arachnids are yet to be named
Stinger receiving the venom. Spiders only bite, although some tarantulas have urticating hairs. Certain caterpillars also have urticating hairs. Organs that perform similar functions in non-arthropods are often referred to as "stings". These organs include the modified dermal denticle of the stingray, the venomous spurs on the hind legs of the male platypus, and the cnidocyte tentacles of the jellyfish. The term "sting" was historically often used for the fang of a snake, although this usage is uncommon today. Snakes are said, correctly, to bite, not sting. Stinger A stinger, or sting, is a sharp organ found in various animals (typically