Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes. Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads. To accommodate their narrow bodies, snakes' paired organs appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca. Lizards have evolved elongate bodies without limbs or with greatly reduced limbs about twenty-five times independently via convergent evolution, leading to many lineages of legless lizards. These resemble snakes, but several common groups of legless lizards have eyelids and external ears, which snakes lack, although this rule is not universal.
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting these criteria. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius or pen, made of chitin.
The king cobra is a species of venomous elapid snake, endemic to tropical jungles in Southern and Southeast Asia. The sole member of the genus Ophiophagus, it is distinguishable from other cobras, most noticeably, by its sheer size plus its unique neck patterns. The king cobra’s size places it as the world's longest venomous snake, with an average length of 3.18 to 4 m, reaching a maximum of 5.85 m (19.2 ft). Its skin colour varies across the habitats, from black with white stripes to unbroken brownish grey. Unlike many other snakes, it rarely consumes mammalian vertebrates, lizards, birds or their eggs/young; similarly to the American kingsnakes, king cobras prey chiefly on other snakes, both venomous and non-venomous, including their own species.
Agkistrodon piscivorus is a species of pit viper in the subfamily Crotalinae of the family Viperidae. It is one of the world's few semiaquatic vipers, and is native to the southeastern United States. As an adult, it is large and capable of delivering a painful and potentially fatal bite. When threatened, it may respond by coiling its body and displaying its fangs. Individuals may bite when feeling threatened or being handled in any way. It tends to be found in or near water, particularly in slow-moving and shallow lakes, streams, and marshes. It is a capable swimmer and, like several species of snakes, is known to occasionally enter bays and estuaries and swim between barrier islands and the mainland.
Elapidae is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydocephalus. Many members of this family exhibit a threat display of rearing upwards while spreading out a neck flap. Elapids are endemic to tropical and subtropical regions around the world, with terrestrial forms in Asia, Australia, Africa, and the Americas and marine forms in the Pacific and Indian Oceans. Members of the family have a wide range of sizes, from the 18 cm (7.1 in) white-lipped snake to the 5.85 m king cobra. Most species have neurotoxic venom which is channeled by their hollow fangs, and some may contain other toxic components in various proportions. The family includes 55 genera with some 360 species and over 170 subspecies.
Rattlesnakes are venomous snakes that form the genera Crotalus and Sistrurus of the subfamily Crotalinae. All rattlesnakes are vipers. Rattlesnakes are predators that live in a wide array of habitats, hunting small animals such as birds and rodents.
The Viperidae (vipers) are a family of snakes found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, and various other isolated islands. They are venomous and have long, hinged fangs that permit deep penetration and injection of their venom. Four subfamilies are currently recognized. They are also known as viperids. The name "viper" is derived from the Latin word vipera, -ae, also meaning viper, possibly from vivus ("living") and parere, referring to the trait viviparity common in vipers like most of the species of Boidae.
Snake venom is a highly toxic saliva containing zootoxins that facilitates in the immobilization and digestion of prey. This also provides defense against threats. Snake venom is injected by unique fangs during a bite, whereas some species are also able to spit venom.
The star-nosed mole is a small semiaquatic mole found in moist, low areas in the northern parts of North America. It is the only extant member of the tribe Condylurini and genus Condylura, and it has more than 25,000 minute sensory receptors in touch organs, known as Eimer's organs, with which this hamster-sized mole feels its way around. With the help of its Eimer's organs, it may be perfectly poised to detect seismic wave vibrations.
The brown tree snake, also known as the brown catsnake, is an arboreal rear-fanged colubrid snake native to eastern and northern coastal Australia, eastern Indonesia, Papua New Guinea, and many islands in northwestern Melanesia. This snake is infamous for being an invasive species responsible for extirpating the majority of the native bird population in Guam. It is also one of the very few colubrids found in Australia, where elapids are more common.
The red-bellied black snake is a species of venomous snake in the family Elapidae, indigenous to Australia. Originally described by George Shaw in 1794 as a species new to science, it is one of eastern Australia's most commonly encountered snakes. Averaging around 1.25 m in length, it has glossy black upperparts, bright red or orange flanks, and a pink or dull red belly. It is not aggressive and generally retreats from human encounters, but can attack if provoked. Although its venom can cause significant illness, no deaths have been recorded from its bite, which is less venomous than other Australian elapid snakes. The venom contains neurotoxins, myotoxins, and coagulants and has haemolytic properties. Victims can also lose their sense of smell.
The yellow-lipped sea krait, also known as the banded sea krait or colubrine sea krait, is a species of venomous sea snake found in tropical Indo-Pacific oceanic waters. The snake has distinctive black stripes and a yellow snout, with a paddle-like tail for use in swimming.
Venomous fish are species of fish which produce strong mixtures of toxins harmful to humans which they deliberately deliver by means of a bite, sting, or stab, resulting in an envenomation. As a contrast, poisonous fish also produce a strong toxin, but they do not bite, sting, or stab to deliver the toxin, instead being poisonous to eat because the human digestive system does not destroy the toxin they contain in their bodies. Venomous fish do not necessarily cause poisoning if they are eaten, as the digestive system often destroys the venom.
Ambush predators or sit-and-wait predators are carnivorous animals that capture or trap prey via stealth, luring or by strategies utilizing an element of surprise. Unlike pursuit predators, who chase to capture prey using sheer speed or endurance, ambush predators avoid fatigue by staying in concealment, waiting patiently for the prey to get near, before launching a sudden overwhelming attack that quickly incapacitates and captures the prey.
Naja annulata, commonly known as the banded water cobra or the ringed water cobra, is a species of water cobra native to western and central Africa.
Coral reef fish are fish which live amongst or in close relation to coral reefs. Coral reefs form complex ecosystems with tremendous biodiversity. Among the myriad inhabitants, the fish stand out as colourful and interesting to watch. Hundreds of species can exist in a small area of a healthy reef, many of them hidden or well camouflaged. Reef fish have developed many ingenious specialisations adapted to survival on the reefs.
Aquatic feeding mechanisms face a special difficulty as compared to feeding on land, because the density of water is about the same as that of the prey, so the prey tends to be pushed away when the mouth is closed. This problem was first identified by Robert McNeill Alexander. As a result, underwater predators, especially bony fish, have evolved a number of specialized feeding mechanisms, such as filter feeding, ram feeding, suction feeding, protrusion, and pivot feeding.
Hydrodynamic reception refers to the ability of some animals to sense water movements generated by biotic or abiotic sources. This form of mechanoreception is useful for orientation, hunting, predator avoidance, and schooling. Frequent encounters with conditions of low visibility can prevent vision from being a reliable information source for navigation and sensing objects or organisms in the environment. Sensing water movements is one resolution to this problem.
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.
