A poison is any chemical substance that is harmful or lethal to living organisms. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broad sense.
Chemical ecology is a vast and interdisciplinary field utilizing biochemistry, biology, ecology, and organic chemistry for explaining observed interactions of living things and their environment through chemical compounds. Early examples of the field trace back to experiments with the same plant genus in different environments, interaction of plants and butterflies, and the behavioral effect of catnip. Chemical ecologists seek to identify the specific molecules that function as signals mediating community or ecosystem processes and to understand the evolution of these signals. The chemicals behind such roles are typically small, readily-diffusible organic molecules that act over various distances that are dependent on the environment but can also include larger molecules and small peptides.
The common garter snake is a species of snake in the subfamily Natricinae of the family Colubridae. The species is indigenous to North America and found widely across the continent. There are several recognized subspecies. Most common garter snakes have a pattern of yellow stripes on a black, brown or green background, and their average total length is about 55 cm (22 in), with a maximum total length of about 137 cm (54 in). The average body mass is 150 g (5.3 oz). The common garter snake is the state reptile of Massachusetts.
The common toad, European toad, or in Anglophone parts of Europe, simply the toad, is a toad found throughout most of Europe, in the western part of North Asia, and in a small portion of Northwest Africa. It is one of a group of closely related animals that are descended from a common ancestral line of toads and which form a species complex. The toad is an inconspicuous animal as it usually lies hidden during the day. It becomes active at dusk and spends the night hunting for the invertebrates on which it feeds. It moves with a slow, ungainly walk or short jumps, and has greyish-brown skin covered with wart-like lumps.
Hognose snake is a common name for several unrelated species of snakes with upturned snouts, classified in two colubrid snake families and one pseudoxyrhophiid snake family.
In evolutionary biology, an evolutionary arms race is an ongoing struggle between competing sets of co-evolving genes, phenotypic and behavioral traits that develop escalating adaptations and counter-adaptations against each other, resembling the geopolitical concept of an arms race. These are often described as examples of positive feedback. The co-evolving gene sets may be in different species, as in an evolutionary arms race between a predator species and its prey, or a parasite and its host. Alternatively, the arms race may be between members of the same species, as in the manipulation/sales resistance model of communication or as in runaway evolution or Red Queen effects. One example of an evolutionary arms race is in sexual conflict between the sexes, often described with the term Fisherian runaway. Thierry Lodé emphasized the role of such antagonistic interactions in evolution leading to character displacements and antagonistic coevolution.
Bufagin is a toxic steroid C24H34O5 obtained from toad's milk, the poisonous secretion of a skin gland on the back of the neck of a large toad (Rhinella marina, synonym Bufo marinus, the cane toad). The toad produces this secretion when it is injured, scared or provoked. Bufagin resembles chemical substances from digitalis in physiological activity and chemical structure.
Venomous snakes are species of the suborder Serpentes that are capable of producing venom, which they use for killing prey, for defense, and to assist with digestion of their prey. The venom is typically delivered by injection using hollow or grooved fangs, although some venomous snakes lack well-developed fangs. Common venomous snakes include the families Elapidae, Viperidae, Atractaspididae, and some of the Colubridae. The toxicity of venom is mainly indicated by murine LD50, while multiple factors are considered to judge the potential danger to humans. Other important factors for risk assessment include the likelihood that a snake will bite, the quantity of venom delivered with the bite, the efficiency of the delivery mechanism, and the location of a bite on the body of the victim. Snake venom may have both neurotoxic and hemotoxic properties. There are about 600 venomous snake species in the world.
Heterodon is a genus of harmless colubrid snakes endemic to North America. They are stout with upturned snouts and are perhaps best known for their characteristic threat displays. Three species are currently recognized. Members of the genus are commonly known as hognose snakes, hog-nosed snakes, North American hog-nosed snakes, and colloquially puff adders.
The eastern hog-nosed snake, is a species of mildly venomous rear-fanged snake in the family Colubridae. The venom is specifically adapted to amphibian prey and is harmless to humans. However, some people may have an allergic reaction, and experience local swelling and other symptoms. The species is endemic to North America. There are no subspecies that are recognized as being valid. This species prefers habitats with sandy soils and a combination of grass fields and forest edges. They come in many different colorations and have the identifiable upturned "snout". They can be found in captivity but are a relatively difficult species to keep due to a specialized diet of toads. As with other Heterodon species, they have a distinctive threat reaction of first bluffing by striking with a closed mouth and then pretending to die if this fails to deter the threat.
Anaxyrus fowleri, Fowler's toad, is a species of toad in the family Bufonidae. The species is native to North America, where it occurs in much of the eastern United States and parts of adjacent Canada. It was previously considered a subspecies of Woodhouse's toad.
Rhabdophis is a genus of snakes in the subfamily Natricinae of the family Colubridae. Species in the genus Rhabdophis are generally called keelback snakes, and are found primarily in Southeast Asia. The best-known species is Rhabdophis tigrinus; few other species have been studied in detail.
The banded water snake or southern water snake is a species of mostly aquatic, nonvenomous, colubrid snakes most commonly found in the Midwest, Southeastern United States.
The parotoid gland is an external skin gland on the back, neck, and shoulder of some frogs, and salamanders. It can secrete a number of milky alkaloid substances known collectively as bufotoxins, which act as neurotoxins to deter predation. These cutaneous glands are called parotoid as they are somewhat similarly positioned to mammalian parotid gland, although the latter have a different function, excreting saliva within the mouth rather than externally excreted defensive chemicals.
Chemical defense is a strategy employed by many organisms to avoid consumption by producing toxic or repellent metabolites or chemical warnings which incite defensive behavioral changes. The production of defensive chemicals occurs in plants, fungi, and bacteria, as well as invertebrate and vertebrate animals. The class of chemicals produced by organisms that are considered defensive may be considered in a strict sense to only apply to those aiding an organism in escaping herbivory or predation. However, the distinction between types of chemical interaction is subjective and defensive chemicals may also be considered to protect against reduced fitness by pests, parasites, and competitors. Repellent rather than toxic metabolites are allomones, a sub category signaling metabolites known as semiochemicals. Many chemicals used for defensive purposes are secondary metabolites derived from primary metabolites which serve a physiological purpose in the organism. Secondary metabolites produced by plants are consumed and sequestered by a variety of arthropods and, in turn, toxins found in some amphibians, snakes, and even birds can be traced back to arthropod prey. There are a variety of special cases for considering mammalian antipredatory adaptations as chemical defenses as well.
Leioheterodon madagascariensis, the Malagasy, Madagascar or Madagascangiant hognose(snake), is a harmless species of pseudoxyrhophiid snake endemic to the island nation of Madagascar. The species is also found on the country's smaller islands of Nosy Be, Nosy Mangabe, and Nosy Sakatia, as well as on the Comoros archipelago, in the Mozambique Channel. It is thought, by some, to have been introduced to the Grande Comoro. Mature giant hognose snakes can measure between 130 and 180 cm (4 ft. to nearly 6 ft., or between 1-2 meters) in length, and be roughly the thickness of an average adult human's arm.
Rhabdophis ceylonensis is endemic to the island of Sri Lanka. The species is commonly known as the Sri Lanka blossom krait, the Sri Lanka keelback, and මල් කරවලා or නිහලුවා (nihaluwa) in Sinhala. It is a moderately venomous snake.
Venom in snakes and some lizards is a form of saliva that has been modified into venom over its evolutionary history. In snakes, venom has evolved to kill or subdue prey, as well as to perform other diet-related functions. While snakes occasionally use their venom in self defense, this is not believed to have had a strong effect on venom evolution. The evolution of venom is thought to be responsible for the enormous expansion of snakes across the globe.
Rhabdophis swinhonis is a species of snake in the subfamily Natricinae of the family Colubridae. The species is endemic to Taiwan. It is also known commonly as the Taiwan keelback and Swinhoe's grass snake.
A toxungen comprises a secretion or other bodily fluid containing one or more biological toxins that is transferred by one animal to the external surface of another animal via a physical delivery mechanism but without direct contact between the secreting animal and the victim. Toxungens can be delivered through spitting, spraying, or smearing. As one of three categories of biological toxins, toxungens can be distinguished from poisons, which are passively transferred via ingestion, inhalation, or absorption across the skin, and venoms, which are delivered through a wound generated by direct contact in the form of a bite, sting, or other such action. Toxungen use offers the evolutionary advantage of delivering toxins into the target's tissues without the need for physical contact. Animals that deploy toxungens are referred to as toxungenous.
