In this article we are going to discover the most poisonous animals on our planet known to date, divided into different categories
Most Poisonous Animals by Category
The Most Poisonous Mammal: The Platypus
The platypus (Ornithorhynchus anatinus), sometimes called the duck-billed platypus, is a semi-aquatic egg-laying mammal endemic to eastern Australia, including Tasmania.
Along with the four echidna species, it is one of five extant species of monotremes. It is one of the few mammals that lay eggs rather than give birth to live young. Like other monotremes, it senses its prey by electrolocalization
It is one of the few venomous mammal species, as the male platypus has a spur on its hind leg that releases a venom, capable of causing severe pain to humans
The unusual appearance of this duck-billed, beaver-tailed, otter-footed mammal puzzled European naturalists when they first encountered it, and the first scientists to examine a preserved platypus carcass (in 1799) judged it to be a fake, made from several animals stitched together.
The platypus’s unique characteristics make it an important subject in the study of evolutionary biology and a recognizable and iconic symbol of Australia. It is culturally important to several Aboriginal peoples of Australia, who also hunted it for food
It has appeared as a mascot at national events and is featured on the reverse side of the Australian twenty-cent coin, and the platypus is the animal emblem of the state of New South Wales
Until the early 20th century, humans hunted the platypus for its fur, but it is now protected throughout its range. Although captive breeding programs have had only limited success, and the platypus is vulnerable to the effects of pollution, it is under no immediate threat.
As of 2020, the platypus is a legally protected species in all states where it occurs. It is listed as an endangered species in danger of extinction in South Australia and Victoria, and has been recommended for listing in New South Wales.
The most venomous bird: Hooded Pitohui
The hooded pitohui (Pitohui dichrous) is a species of bird in the genus Pitohui found in New Guinea. Long thought to be a whistler (Pachycephalidae), it is now known to belong to the Old World oriole family (Oriolidae)
This species, a medium-sized songbird with rich chestnut and black plumage, is one of the few known poisonous birds, as it contains a number of batrachotoxin compounds in its skin, feathers, and other tissues. These toxins are believed to be derived from its diet, and may function both to deter predators and to protect the bird from parasites
The close resemblance of this species to other unrelated birds known as pitohuis that are also venomous is an example of convergent evolution and mullerian mimicry. Its appearance is also mimicked by unrelated species that are not venomous, a phenomenon known as Batesian mimicry. The toxic nature of this bird is well known to local hunters, who avoid it. It is one of the most poisonous species of pitohui, but the toxicity of individual birds can vary geographically.
The hooded pitohui is found in forests from sea level to 2,000 m, but is more common in the hills and low mountains. It is a social bird, living in family groups and often joins and even leads mixed-species foraging flocks. Its diet consists of fruits, seeds and invertebrates
This species is apparently a cooperative breeder, with family groups helping to protect the nest and feed the young. The hooded pitohui is common and currently not endangered, as its numbers are stable.
The most venomous jellyfish: Box jellyfish
Box jellyfish (class Cubozoa) are cnidarian invertebrates distinguished by their box-shaped (i.e., cube-shaped) bodies. Some species of box jellyfish produce a potent venom that is administered by contact with their tentacles.
The stings of some species, such as Chironex fleckeri, Carukia barnesi, Malo kingi and a few others, are extremely painful and often fatal to humans.
The nervous system of the box jellyfish is more developed than that of many other jellyfish. They possess a nerve ring around the base of the bell that coordinates their pulsating movements, a feature found only in crown jellyfish.
While other jellyfish have simple pigmented ocelli, box jellyfish are unique in possessing true eyes, with retinas, corneas and lenses
Their eyes are found in clusters called rhopalia, located in pockets midway along the outer flat surfaces of the bell. Each contains two rhopal ocelli with lenses, one directed upward and the other downward and toward the inside of the manubrium, allowing the animal to see specific points of light, rather than simply distinguishing between light and dark
They also have twenty ocelli (simple eyes) that do not form images, but rather detect light and dark; thus, they have a total of twenty-four eyes. Near the rhopalia are statoliths that detect gravitational attraction and help the animal orient itself.
Box jellyfish actively hunt their prey (small fish), rather than drifting like true jellyfish. They are capable of speeds up to 1.5 to 2 meters per second or about 4 knots (7.4 km/h; 4.6 mph)[16].
The venom of cubozoans is distinct from that of scyphozoans, and is used to capture prey (small fish and invertebrates, including shrimp and baitfish) and to defend against predators, including butterfish, batfish, rabbitfish, crabs (blue swimming crab), and several species of turtles, including hawksbill and flatback turtles.
Sea turtles are apparently not affected by stings, as they seem to enjoy box jellyfish.
Most venomous snake: Inland Taipan Snake
The inland taipan (Oxyuranus microlepidotus), also commonly known as the western taipan, small-scaled snake, or fierce snake, is an extremely venomous species of snake in the family Elapidae. The species is endemic to the semi-arid regions of central-eastern Australia
The Australian Aborigines living in these regions called the snake dandarabilla. It was first described by Frederick McCoy in 1879 and then by William John Macleay in 1882, but for the next 90 years it was a mystery to the scientific community; no further specimens were found and virtually nothing was added to the knowledge of this species until its rediscovery in 1972.
Based on the mean lethal dose value in mice, the venom of the inland taipan is by far the most toxic of any snake – far more than even sea snakes and has the most toxic venom of any reptile when tested in a human heart cell culture.
It is a specialized mammal hunter, so its venom is specially adapted to kill warm-blooded species. One bite is estimated to be lethal enough to kill at least 100 adult humans. It is an extremely fast and agile snake that can strike instantly with extreme precision, often striking several times in the same attack, and it poisons in almost all cases.
Although it is the most venomous and capable of attacking, in contrast to the coastal taipan, which many experts cite as an extremely dangerous snake due to its behavior when encountering humans, the inland taipan is usually a rather shy and reclusive snake, with a placid disposition and prefers to escape trouble. However, it will defend itself and attack if provoked, mishandled, or prevented from escaping
Because it lives in such remote locations, the inland taipan rarely comes into contact with people, so it is not considered the world’s deadliest snake overall, especially in terms of disposition and human deaths per year, The word “fierce” in its alternate name describes its venom, not its temperament.
The most venomous mollusk: Cone Snails
Cone snails are a large group of small to large predatory marine snails, marine gastropod mollusks.
Until recently, more than 600 species of cone snails were classified in a single genus, Conus, in a single family, the Conidae. However, in recent years, it was suggested that cone snails should occupy only one subfamily that should be divided into a very large number of genera
Fossils of cone snails are known from the Eocene to the Holocene. Cone snail species have more or less conical shells (hence their common name). Many species have color patterns on the shell surface. Cone snails are almost all tropical in distribution.
All cone snails are poisonous and can “sting” humans; if handled alive, their poisonous sting occurs without warning and can be fatal. The most dangerous species to humans are the larger cone snails, which feed on small bottom-dwelling fish; the smaller species hunt and eat mainly marine worms.
Cone snails use a modified radula tooth similar to a hypodermic needle and a poison gland to attack and paralyze their prey before engulfing it. The tooth, which is sometimes compared to a dart or harpoon, is barbed and may extend some distance from the snail’s head at the end of the proboscis.
The venoms of cone snails are mainly peptides. The venoms contain many different toxins that vary in their effects; some are extremely toxic. The sting of small snails is no worse than that of a bee, but the sting of some of the larger species of tropical snails can be serious and sometimes even fatal to humans
The venom of cone snails holds great promise as a source of new medically important substances.
The most venomous fish: Stonefish
Synanceia is a genus of ray-finned fish belonging to the subfamily Synanceiinae, the stonefishes, which is classified within the family Scorpaenidae, the scorpionfishes and related fishes
Stonefishes are poisonous, dangerous and deadly to humans. They are the most poisonous fish known. They are found in the coastal regions of the Indo-Pacific.
Stonefish are primarily marine and, although some species are known to live in rivers, most live in coral reefs near the tropical Pacific and Indian Oceans.
This species has potent neurotoxins secreted by glands located at the base of its needle-like dorsal fin spines that protrude when disturbed or threatened.
The species’ vernacular name, the stonefish, derives from its gray, mottled camouflage, similar to the color of a stone. Swimmers may not notice and inadvertently step on them, resulting in a sting. When stonefish are disturbed, they can inject an amount of venom proportional to the amount of pressure applied to them.
A study published in 2018 reports that stonefish also have the ability to extend a sharp, specialized spine known as a lachrymal saber as an additional defense mechanism.
Synanceia venom is potent and can cause cellular deterioration of the affected organism due to toxins that target cell membranes. The venom can also reduce the white blood cell count and cause infection of the area even after proper wound treatment.
Most Venomous Lizard: Mexican Beaded Lizard
The Mexican beaded lizard (Heloderma horridum) is a species of lizard in the family Helodermatidae, one of two species of venomous beaded lizards found primarily in Mexico and southern Guatemala. Along with the other member of the same genus, the Gila monster (Heloderma suspectum), they are the only lizards known to have evolved a venom delivery system
The Mexican beaded lizard is larger than the Gila monster, with duller coloration, black with yellowish bands. As it is a specialized predator that feeds primarily on eggs, the primary use of its venom remains a source of debate among scientists. This venom has been found to contain several enzymes useful for the manufacture of drugs in the treatment of diabetes, and pharmacological use of its venom is under investigation.
Threatened throughout its range by over-collection and habitat loss, it is a CITES protected species. The Guatemalan beaded lizard (H. charlesbogerti) is one of the rarest lizards in the world, with a wild population of less than 200 individuals.
The venom glands of the beaded lizard are modified salivary glands located in the lower jaw of the reptile. Each gland has a separate duct leading to the base of its grooved teeth. When it bites, the beaded lizard hangs onto its victim and chews to get its venomous saliva into the wound. Although its jaw grip is strong, its nonengaging teeth break easily at their bases
The beaded lizard’s venom is a weak hemotoxin and, although human fatalities are rare, it can cause respiratory failure. It consists of a number of components, including L-amino acid oxidase, hyaluronidase, phospholipase A, serotonin, and highly active kallikreins that release vasoactive kinins. The venom contains no enzymes that significantly affect coagulation. Nearly all documented human bites (eight in the last century) have resulted from poking captive lizards with a finger or bare foot.
While invertebrates are essentially immune to the effects of this venom, the effects on vertebrates are more severe and varied. In mammals such as rats, the main effects include a rapid reduction in carotid blood flow followed by a marked drop in blood pressure, respiratory irregularities, tachycardia and other cardiac abnormalities, as well as hypothermia, edema and internal hemorrhage in the gastrointestinal tract, lungs, eyes, liver and kidneys.
In humans, the effects of bites are associated with excruciating pain that may extend beyond the bitten area and persist for up to 24 hours. Other common effects of bites in humans are local edema (swelling), weakness, sweating, and a rapid drop in blood pressure. Beaded lizards are immune to the effects of their own venom.
Most Venomous Spider: Funnel-web spiders
Atracidae is a family of megalomorph spiders, commonly known as Australian funnel-web spiders or atracidae
All members of the family are native to Australia Atracidae consists of three genera: Atrax, Hadronyche and Illawarra, comprising 35 species
Some members of the family produce venom dangerous to humans, and spider bites from six of the species have caused serious injury to victims. Bites from the Sydney funnel-web spider (Atrax robustus) and the northern tree funnel-web spider (Hadronyche formidabilis) are potentially fatal, but no deaths have occurred since the introduction of modern first aid techniques and antivenoms.
They have extensive venom glands that are located entirely within their chelicerae. Their fangs are large and powerful, capable of penetrating fingernails and soft shoes.
Australian funnel-web spiders burrow in moist, cool, sheltered habitats: under rocks, in and under decaying logs, and some in rough-barked trees (occasionally meters above the ground)
They are commonly found in suburban rock gardens and shrubs, and rarely in lawns or other open ground. The burrow is characterized by irregular silk lines radiating from the entrance Unlike some related trapdoor spiders, they do not build lids on their burrows.
Most Venomous Insect: Maricopa Harvester Ant
Pogonomyrmex maricopa, the Maricopa harvester ant, is one of the most common species of harvester ants found in the U.S. state of Arizona, but is also known in California, Colorado, New Mexico, Nevada, Texas and Utah, and in the Mexican states of Baja California, Chihuahua, Sinaloa and Sonora. Its venom is believed to be the most toxic insect venom in the world.
Their nest mounds often incorporate rocks and gravel. The ants build cemented plugs in the sand mound nests in an area of fine sand dunes
The plugs consist of 60% calcium carbonate transported from the underlying calcium carbonate layers, and protect the nest structure from erosion during periods of high winds. Partial erosion of the cemented caps adds calcium carbonate to the dune soils.
The toxicity of Maricopa harvester ant venom is well known. Its LD50 value is 0.12 mg/kg (injected intravenously into mice); 12 stings can kill a 2 kg rat. In comparison, the LD50 of the honey bee is 2.8 mg/kg, i.e. less than 1/20th of its potency.
In humans, a Pogonomyrmex sting produces intense pain that can last up to four hours.
Like that of many venomous insects, the venom of the Maricopa harvester ant is composed of amino acids, peptides and proteins. It may also include alkaloids, terpenes, polysaccharides, biogenic amines and organic acids.
The most notable component found in the venom of the Maricopa harvester ant is an alkaloid venom, which releases an“alarm” pheromone that chemically alerts other ants in the vicinity. This is an example of chemical signaling, which explains why ants seem to sting all at once.
Similar to the two-part process of the fire ant bite and sting, the harvester ant attaches to the victim with its mandibles, and thus proceeds by pivoting around the site, allowing the ant to sting repeatedly and inject venom into the region.
The Maricopa harvester ant plays an important role in decomposition by dragging insect carcasses underground, thus enriching the soil for plants and crops.
The most venomous amphibian: The golden poison frog
The golden poison frog (Phyllobates terribilis), also known as the golden poison frog or golden arrow poison frog, is a poison frog endemic to the tropical forests of Colombia
The golden poison frog is endangered due to habitat destruction within its naturally limited range. Despite its small size, this frog is probably the most venomous animal on the planet.
Golden poison frogs are so toxic that adult frogs are likely to have few or no predators. The snake species Leimadophis epinephelus has shown resistance to several frog toxins, including batrachotoxin, and has been observed to eat young frogs with no ill effects.
These frogs produce the deadly alkaloid batrachotoxin in their skin glands as a defense against predators. To become poisoned a predator must generally attempt to consume the frog, although this species is so toxic that even touching an individual frog can be dangerous
This extraordinarily lethal poison is very rare. Batracotoxin is only found in three poison frogs in Colombia (all of the genus Phyllobates), a few birds in Papua New Guinea, and four Papuan beetles of the genus Choresine of the family Melyridae.
Batrachotoxin affects sodium channels in nerve cells, but the frog has modified sodium channels that are not affected by batrachotoxin.
