This article is about animals that inject venom. For animals poisonous on contact or when ingested, see list of poisonous animals.
Many venomous animals, such as this greater blue-ringed octopus (Hapalochlaena lunulata), are brightly colored or can display bright colors to warn potential predators
Numerous animal species naturally produce chemical toxins which are used to kill or incapacitate prey or as a defense against predators.
Venomous animals actively deliver their toxins (called venom) into their target through a specially designed mechanism, such as a bite or sting, by using a venom apparatus, such as fangs or a stinger, in a processes called envenomation.[1][2]
They are often distinguished from poisonous animals, which instead passively deliver their toxins (called poison) to their victims upon contact such as through inhalation, absorption through the skin, or after being ingested.[1][2][3] The only difference between venomous animals and poisonous animals is how they deliver the toxins.[3] This list deals exclusively with venomous animals.
Venoms have adapted to serve a wide variety of purposes. Their intended effects can range from mild fleeting discomfort to paralysis and death, and they may be highly selective in which species they target, often making them harmless to all but a few specific organisms; what may be fatal to one species may be totally insignificant to another species. Because the definition of "venomous" can be extremely broad, this list includes only those animals with venom that is known or suspected to be medically significant for humans or domestic animals.
Strictly speaking, all spiders and scorpions possess venom, though only a handful are dangerous to humans. Spiders typically deliver their venom with a bite from piercing, fang-like chelicerae; scorpions sting their victims with a long, curved stinger mounted on the telson.
All widow spiders (Latrodectus spp.), including the black widows, button spiders, Australian redback spider (L. hasseltii), and the endangered katipō of New Zealand (L. katipo)
Of more than a thousand known species of scorpion, only a few dozen have venom that is dangerous to humans,[6] most notably the bark scorpions, including:
The remipedeXibalbanus tulumensis is a centipede-like crustacean that lives in underground anchialine caves of Mexico and Central America. Although blind, it is a formidable predator and feeds on the shrimp that share its underground pools.[7]
Mollusks
Cone snails of the family Conidae are a diverse group of predatory marine gastropods, mostly tropical in distribution, which hunt and immobilize prey using a modified harpoon-like radular tooth that can deliver neurotoxic conopeptides. All cone snails are venomous, though the danger posed to humans varies widely by species.
Many species of octopus, squid, and cuttlefish make use of venom when hunting their prey.
The blue-ringed octopodes (Hapalochlaena spp.) produce tetrodotoxin, which is extremely toxic to even the healthiest adult humans, though the number of actual fatalities they have caused is far lower than the number caused by spiders and snakes, with which human contact is more common.[8]
Cnidarians
Jellyfish sting using microscopic cells called nematocysts, which are capsules full of venom expelled through a microscopic lance. Contact with a jellyfish tentacle can trigger millions of nematocysts to pierce the skin and inject venom.[9]
Chaetognathans, known as arrow worms, use the grasping spines in front of their mouth to catch prey and inject them with tetrodotoxin produced by symbiotic bacteria.[11][12]
Annelids
Glyceridae, also called bloodworms, is a family of carnivorous polychaete worms which have an eversible proboscis equipped with four jaws connected to venom glands, used for killing the invertebrates they feed on.[13]
Synanceia verrucosa, a species of stonefish, is lined with dorsal spines that deliver an intensely painful and lethal venom. It is sometimes called the most venomous fish in the world.
There are at least 1,200 species of venomous fish, including:
Some scientists have proposed that Sinornithosaurus had a venomous bite, but recent evidence suggests otherwise.[16]
Amphibians
Though there are numerous poisonous amphibian species capable of secreting lethal toxins through their skin, relatively few amphibians are truly venomous.
Only a few modern mammal species are capable of producing venom; they are likely the last living examples of what was once a more common trait among the mammals. The definition of "venomous" becomes less distinct here, however, and whether some species are truly venomous is still debated.
^The venom is produced only by the male and only during the breeding season.
References
^ abGupta, Ramesh C. (24 March 2017). Reproductive and developmental toxicology. Saint Louis. pp. 963–972. ISBN978-0-12-804240-3. OCLC980850276.{{cite book}}: CS1 maint: location missing publisher (link)
^ abChippaux, JP; Goyffon, M (2006). "[Venomous and poisonous animals--I. Overview]". Médecine Tropicale (in French). 66 (3): 215–20. ISSN0025-682X. PMID16924809.
^Gianechini, F.A., Agnolín, F.L. and Ezcurra, M.D. (2010). "A reassessment of the purported venom delivery system of the bird-like raptor Sinornithosaurus." Paläontologische Zeitschrift, in press. doi:10.1007/s12542-010-0074-9