The poison dart frog is the common name given to the most poisonous animals on Earth.

Native to Central and South America, these species of frogs (family: Dendrobatidae) produce several lethal toxins that are capable of killing a human or other large animal with just 2 micrograms (μg). In other words, one drop of their venom could be powerful enough to kill 8000 people.

The most toxic of poison dart frog species is Phyllobates terribilis. Unlike snakes, dart frogs do not synthesize their poisons, but sequester the chemicals they consume from arthropod prey, such as ants, centipedes and mites. This is why in captivity, they produce far less poison than wild frogs due to their change in diet. What makes these frogs immune to their own poison i ...

The manchineel tree (Hippomane mancinella) has taken the title of world’s most dangerous tree. This evergreen grows up to 15 metres (49 ft) tall, and is native to tropical southern North America and northern South America. It has reddish-greyish bark, small greenish-yellow flowers, and shiny green leaves ranging in size from 5 to 10 cm (2–4 inches) long.

All parts of the tree contain strong toxins, some unidentified. The leaves and fruit of the tree superficially resemble an apple tree, however one bite of the tree’s fruit can cause abdominal pain, vomiting, bleeding, or death due to an acetylcholine inhibitor known as physostigmine found in the fruit. In addition, its milky white sap contains phorbol and other skin irritants, producing s ...

Some organisms, such as the castor bean plant (Ricinus communis), produce substances that inhibit the synthesis of proteins (called translation) within a cell. (The plant, which is native to Africa, is not related to the species of bean plants with which you are likely more familiar.) A protein called ricin, produced within the castor seeds is an extremely potent inhibitor of protein synthesis. In fact, it is one of the strongest natural toxins produced. A single chewed seed can kill child! If the ricin were purified, it would take an amount equivalent to only a few grains of salt to kill an adult. Ricin kills cells by enzymatically cleaving covalent bonds within the large and small ribosomal subunits, rendering the protein-building factori ...

The hammerhead worm is a master of regeneration. Cut one into eight pieces, and you'll get seven new hammerhead worms. Twice a month they'll reproduce by deliberately sticking their tails to the ground, pulling them off, and that tail will become a new hammerhead worm.

Meet the guineafowl puffer (Arothron meleagris), all puffed-up and poisonous to deter any would-be predators. Found throughout the Indo-Pacific and Eastern Pacific Oceans, this spotty species loves feeding on tiny marine invertebrates and the tips of coral.

The Bushveld rain frog is found in Southern Africa. When threatened, it puffs itself up to ward off potential attackers.

The frogs are sexually dimorphic, and the male is too small to mount the female properly to reproduce. The white secretion you see on the back of the frog is actually an adhesive that holds the male in place during copulation.