Prey in the context of "Cnidarians"

Cnidaria (/nɪˈdɛəriə, naɪ-/ nih-DAIR-ee-ə, ny-) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in freshwater and marine environments (predominantly the latter), including jellyfish, hydroids, sea anemones, corals and some of the smallest marine parasites. Their distinguishing features are an uncentralized nervous system distributed throughout a gelatinous body and the presence of cnidocytes or cnidoblasts, specialized cells with ejectable organelles used mainly for envenomation and capturing prey. Their bodies consist of mesoglea, a non-living, jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick. Many cnidarian species can reproduce both sexually and asexually.

Cnidarians mostly have two basic body forms: swimming medusae and sessile polyps, both of which are radially symmetrical with mouths surrounded by tentacles that bear cnidocytes, which are specialized stinging cells used to capture prey. Both forms have a single orifice and body cavity that are used for digestion and respiration. Many cnidarian species produce colonies that are single organisms composed of medusa-like or polyp-like zooids, or both (hence they are trimorphic). Cnidarians' activities are coordinated by a decentralized nerve net and simple receptors. Cnidarians also have rhopalia, which are involved in gravity sensing and sometimes chemoreception. Several free-swimming species of Cubozoa and Scyphozoa possess balance-sensing statocysts, and some have simple eyes. Not all cnidarians reproduce sexually, but many species have complex life cycles of asexual polyp stages and sexual medusae stages. Some, however, omit either the polyp or the medusa stage, and the parasitic classes evolved to have neither form.

Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptiles, birds, fish, and insects, both in predators and in prey.

When light falls from above on a uniformly coloured three-dimensional object such as a sphere, it makes the upper side appear lighter and the underside darker, grading from one to the other. This pattern of light and shade makes the object appear solid, and therefore easier to detect. The classical form of countershading, discovered in 1909 by the artist Abbott Handerson Thayer, works by counterbalancing the effects of self-shadowing, again typically with grading from dark to light. In theory this could be useful for military camouflage, but in practice it has rarely been applied, despite the best efforts of Thayer and, later, in the Second World War, of the zoologist Hugh Cott.

Fishing bait is any luring substance used specifically to attract and catch fish, typically when angling with a hook and line. There are generally two types of baits used in angling: hookbaits, which are directly mounted onto fish hooks and are what the term "fishing bait" typically refers to; and groundbaits, which are scattered separately into the water as an "appetizer" to attract the fish nearer to the hook. Despite the bait's sole importance is to provoke a feeding response out of the target fish, the way how fish react to different baits is quite poorly understood.

Fishing baits can be grouped into two broad categories: natural baits and artificial baits. Traditionally, fishing baits are natural food or prey items (live or dead) that are already present in the fish's normal diet (e.g. worms, insects, crustaceans and smaller bait fish), and such baits are both procured from and used within the same environment. Artificial baits, conversely, are not naturally acquired and must involve some kind of production process. These can be processed foods (e.g. bread, cheese, dough, cutlets, fish food or pet food pellets, etc.), commercially made feed mixtures (e.g. boilies), or imitative replica "fake foods" made of inedible materials known as lures (e.g plastic worm, swimbaits, spoons, stickbaits, hybrid spinners or even bionic robot fish). The variety of baits that a fisherman may choose is dictated mainly by the target species and by its habitat, as well as personal preference. Both natural and artificial baits frequently demonstrate similar efficiency if chosen adequately for the target fish. The overall bait type, size and techniques used will affect the efficiency and yield when fishing.

A fishing lure is any of a broad category of inedible, artificial fishing baits designed to be "fake food" that mimic the appearances of prey and thus attract the attention of predatory fish when angling. Lures come in many shapes and designs that impart different actions and vibrations, which appeal to fish's foraging/territorial instincts and provoke them into striking. Lure color, brightness or the metallic shine/flash alone may also contribute to fish striking a lure, but much of the time even clear hard or soft plastic lures will get struck as well as those made of fur, metal, wood, soft and hard plastic or skirts made of feather, rubber or silicone strands. Lures can be commercially made and purchased from tackle shops, or hand-made by anglers (as in the case of hand-tied fly lures).

Fishing lures are attached to a fishing line, and attached to at least one hook (commonly a treble hook). When lure fishing, the angler use a rod to cast or simply drop the lure to an area of water and then steadily retrieve the lure back, in the hope that lure movements and splashes against the water current will entice nearby fish into striking. Typically, the line is stored on a reel spool and cranked back in retrieval, but in handlining and ice fishing the line might be pulled by hand or tethered directly to a very short rod. Trolling or dragging a lure behind a moving boat is also an effective way to cover water and provoke fish to strike. The retrieve of a lure is as important as the lure cast and there are many types of retrieves, most are tailored to the lure, how it is used and where it is placed, i.e. what depth and/or near objects in the water such as plants or docks. Lures are search tools that find fish apt to strike something they have no clue is dangerous.

An artificial fly or fly lure is a type of fishing lure, usually used in the sport of fly fishing (although they may also be used in other forms of angling). In general, artificial flies are an imitation of aquatic insects that are natural food of the target fish species the fly fishers try to catch. Artificial flies are constructed by fly tying, in which furs, feathers, thread or any of very many other materials are tied onto a fish hook.

Artificial flies may be constructed to represent all manner of potential preys to freshwater and saltwater fish, including aquatic and terrestrial insects, crustaceans, worms, spawn, small baitfish, reptiles, amphibians, mammals and even birds. Effective artificial fly patterns are said to be killing flies because of their ability to put fish in the creel for the fly fisher. There are thousands of artificial fly patterns, many of them with descriptive and often idiosyncratic names.

The bird family Sulidae comprises the gannets and boobies. Collectively called sulids, they are medium-large coastal seabirds that plunge-dive for fish and similar prey. The 10 species in this family are often considered congeneric in older sources, placing all in the genus Sula. However, Sula (true boobies) and Morus (gannets) can be distinguished via morphological, behavioral, and DNA sequence characters. Abbott's booby (Papasula) is given its own genus, as it stands apart from both in these respects. It appears to be a distinct and ancient lineage, maybe closer to the gannets than to the true boobies.

A cursorial organism is one that is adapted specifically to run. An animal can be considered cursorial if it has the ability to run fast (e.g. cheetah) or if it can keep a constant speed for a long distance (high endurance). "Cursorial" is often used to categorize a certain locomotor mode, which is helpful for biologists who examine behaviors of different animals and the way they move in their environment. Cursorial adaptations can be identified by morphological characteristics (e.g. loss of lateral digits as in ungulate species), physiological characteristics, maximum speed, and how often running is used in life. Much debate exists over how to define a cursorial animal specifically. The most accepted definitions include that a cursorial organism could be considered adapted to long-distance running at high speeds or has the ability to accelerate quickly over short distances. Among vertebrates, animals under 1 kg of mass are rarely considered cursorial, and cursorial behaviors and morphology are thought to only occur at relatively large body masses in mammals. A few mammals have been termed "micro-cursors" that are less than 1 kg in mass and have the ability to run faster than other small animals of similar sizes.

Some species of spiders are also considered cursorial, as they walk much of the day, looking for prey.

A pack hunter or social predator is a predatory animal which hunts its prey by working together with other members of its species. Normally animals hunting in this way are closely related, and with the exceptions of chimpanzees where only males normally hunt, all individuals in a family group contribute to hunting. When hunting cooperation is across two or more species, the broader term cooperative hunting is commonly used.

A well known pack hunter is the gray wolf; humans too can be considered pack hunters. Other pack hunting mammals include chimpanzees, dolphins including orcas, lions, dwarf and banded mongooses, as well as spotted hyenas. Avian social predators include the Harris's hawk, butcherbirds, three of four kookaburra species and many helmetshrikes. Other pack hunters include ants like army ants, the goldsaddle goatfish, and occasionally crocodilians.