The American bullfrog (Lithobates catesbeianus), often simply known as the bullfrog in Canada and the United States, is a large true frog native to eastern North America. It typically inhabits large permanent water bodies such as swamps, ponds, and lakes. Bullfrogs can also be found in manmade habitats such as pools, koi ponds, canals, ditches and culverts. They prefer warm, slow or stagnant waters with abundant vegetation, but are also found along the shorelines of lakes and banks of streams. The bullfrog gets its name from the sound the male makes during the breeding season, which sounds similar to a bull bellowing. The bullfrog is large and is commonly eaten throughout its range, especially in the southern United States where they are plentiful. The dorsal (upper) surface of the bullfrog has an olive-green basal color, either plain or with mottling and banding of grayish brown. The ventral (under) surface is off-white blotched with yellow or gray. Often, a marked contrast in color is seen between the green upper lip and the pale lower lip. The teeth are tiny and are useful only in grasping. The eyes are prominent with brown irises and horizontal, almond-shaped pupils. The tympana (eardrums) are easily seen just behind the eyes and the dorsolateral folds of skin enclose them. The limbs are blotched or banded with gray. The fore legs are short and sturdy and the hind legs long. The front toes are not webbed, but the back toes have webbing between the digits with the exception of the fourth toe, which is unwebbed. Bullfrogs are sexually dimorphic, with males being smaller than females and having yellow throats. Males have tympana larger than their eyes, whereas the tympana in females are about the same size as the eyes. Bullfrogs measure about 3.6 to 6 in (9 to 15 cm) in snout–to–vent length. They grow fast in the first eight months of life, typically increasing in weight from 5 to 175 g (0.18 to 6.17 oz), and large, mature individuals can weigh up to 500 g (1.1 lb). In some cases bullfrogs have been recorded as attaining 800 g (1.8 lb) and measuring up to 8 in (20 cm) from snout to vent. The American bullfrog is the largest species of true frog in North America. Bullfrogs are ambush predators and will eat almost any animal they can capture and swallow, including worms, insects, crayfish, fishes, other frogs, snakes, small turtles, small mammals and even birds. Animals such as snapping turtles, foxes, herons, and raccoons eat Bullfrogs. Most breeding takes place between April and August. The male grasps the female and externally fertilizes eggs produced by female as she deposits them in water. Clutch size can be up to 12,000 eggs. Females may produce up to three clutches per breeding season. Bullfrogs can live seven to 10 years.

The cookiecutter shark, also called the cigar shark, is a species of small squaliform shark in the family Dalatiidae. This shark occurs in warm, oceanic waters worldwide, particularly near islands, and has been recorded as deep as 3.7 km. This small, cigar-shaped shark is dark brown on top and light on the underside, with a darker band around its neck. The light underside glows, attracting fish, whales, and sharks. It attaches itself to the prey and uses its serrated bottom teeth to cut out a perfectly circular chunk of flesh. Cookiecutter sharks are poor swimmers, and generally only caught at night. They probably migrate vertically from deep water [2000-3000 m] to midwater or surface at night. They are an ectoparasite on large fish and cetaceans, which are possibly lured to the shark by its bioluminescent light organs. Cookiecutter sharks live in the warm, deep waters of equatorial oceans, primarily in coastal waters near islands. They inhabit deep waters below 1,000 m during the day and migrate into surface waters at night at around 300 m. They eat smaller animals (like squid) whole, but also take large, round cookie-cutter shaped bites out of larger animals, such as tuna, whales, dolphins, and seals. Potential predators of the cookiecutter shark include large sharks and bony fish. The cookiecutter shark is ovoviviparous, meaning it gives birth to live pups after they develop inside egg cases within the uterus of the mother. Each developing pup feeds off the yolk inside the egg case, remaining there until it is fully developed. Like all sharks, cookiecutter sharks lose several sets of teeth throughout their lifetimes. This process ensures that they always have sharp, healthy teeth capable of feeding by their preferred strategy. Unlike other species, though, cookiecutter sharks apparently purposely swallow the teeth that they lose.

The whirligig beetles are water beetles, comprising the family Gyrinidae that usually swim on the surface of the water if undisturbed, though they swim underwater when threatened. Whirligigs can be distinguished from all other beetles by their short, clubbed antennae and their two pairs of compound eyes — one pair above the water, and one pair below — which helps them to quickly and accurately capture their prey while also evading predators. Whirligig beetles occur in many types of aquatic habitats, including ponds, lakes and streams. They can swim almost as effortlessly underwater as they do on the surface, making them difficult to catch. Their wings are well developed, so whirligigs can fly to a new home if their pond or stream should dry up. These beetles and their larvae are carnivorous. The larvae eat other aquatic insects and invertebrates. The adults often feed on land insects that fall into the water. These beetles are generally preyed upon by any predator bigger than itself. Concerning reproduction Females lay eggs on emergent vegetation or debris just below the water surface. After hatching in 1–2 weeks, larvae pass through three instars. Larvae are found on submerged objects where they feed on small aquatic insects. Pupal chambers are constructed in mud just above the water level. Here is a video so you can see the whirligig’s whirling.

Aquarius remigis, known as the common water strider, is a species of aquatic bug. It was formerly known as Gerris remigis, but the subgenus Aquarius was elevated to generic rank in 1990 on the basis of phylogenetic analysis. Aquarius remigis is found throughout North America, but is most prevalent in the mid-west of the United States. Aquarius remigis grows slightly longer than . 5 inches, and is dark brown to black in colour. It has a sharp rostrum that it uses to pierce the body of its prey and suck out the insides. They normally continue to move to avoid being eaten by predators. It has good vision, and can row quickly over the surface of the water. It uses its front legs to seize its prey. During breeding season, this species can communicate with potential mates by sending ripples over on the surface of the water. This predatory species feeds on mosquito larvae living under the surface, and dead insects on the surface, and other insects that accidentally land on the water. This bug is can eaten by any predator bigger than it, frogs, birds, and even fish prey on these insects.

The giant oarfish (Regalecus glesne) is a species of oarfish of the family Regalecidae. It is an oceanodromous species with a worldwide distribution, excluding polar regions. Other common names include Pacific oarfish, king of herrings, ribbonfish, and streamer fish. R. glesne is the world's longest ray-finned fish. The long, flat, tapering body is reflective silver with a dorsal fin running the length of it that it uses to swim and turn with. Its abrupt, slightly concave profile is set with a toothless mouth ideal for filtering krill and crustaceans out of the water. This species is the world's longest bony fish, reaching a record length of 17 m (56 ft). It is commonly measured to 3 m (9.8 ft) in total length. An oceanic species, the oarfish is found living at great depths to 3,280 feet (1,000 m) but more typically to depths of 656 feet (200 m). It is occasionally found cast upon beaches after storms or near the surface when injured or dying. Oarfish feed on plankton, crustaceans, and squid by straining them from the water column using specially evolved gill rakes located in the mouth. They orient themselves vertically within the water column which is theorized to allow them to spot the silhouettes of prey items. Then they use their protrusible mouths to suck in prey items including plankton, squid, fish and euphausiid crustaceans which are then strained out of the water by the gill rakers. There is some speculation that they may also steal food items from siphonophores. Due to its significant size, larger fish including sharks are the primary potential predators of the oarfish. Oarfishes, are oviparous broadcast spawners and spawn in warm waters between July and December. After fertilization its large eggs pelagic eggs (2-4 mm) remain near the ocean’s surface until hatching after about three weeks. The resulting larvae have the appearance of miniature adults and feed on plankton until they mature.

Black seadevils are small, deepsea lophiiform fishes of the family Melanocetidae. The five known species are all within the genus Melanocetus. They are found in tropical to temperate waters of the Atlantic, Indian, and Pacific Oceans, with one species known only from the Ross Sea. One of several anglerfish families, black seadevils are named for their baleful appearance and typically pitch black skin. Black seadevils are characterised by a gelatinous, mostly scaleless, globose body, a large head, and generous complement of menacingly large, sharp, glassy, fang-like teeth lining the jaws of a cavernous, oblique mouth. These teeth are depressible and present only in females. Some species have a scattering of epidermal spinules on the body, and the scales (when present) are conical, hollow, and translucent. Like other anglerfishes, black seadevils possess an illicium and esca; the former being a modified dorsal spine—the "fishing rod"—and the latter being the bulbous, bioluminescent "fishing lure". The esca is simple in black seadevils (with either a conical terminus or anterior and posterior ridges in some species), and both it and the illicium are free of denticles. The bioluminescence is produced by symbiotic bacteria; these bacteria are thought to enter the esca via an external duct (in at least two species, the esca is not luminous until this duct develops, suggesting the bacteria originate from the surrounding seawater). The bacteria, belonging to the family Vibrionaceae, are apparently different in each anglerfish species; the bacteria have yet to be cultured in vitro. The eyes of black seadevils are small; the pupil is larger than the lens, leaving an aphakic space. Common among deepsea anglerfish is the strong sexual dimorphism in melanocetids: while females may reach a length of 18 cm (7 in) or more, males remain under 3 cm (1 in). Aside from jaw teeth, males also lack lures. Pelvic fins are absent in both sexes. All fins are rounded with slightly incised membranes; the pectoral fins are small. The single dorsal fin is positioned far back from the head, larger than and above the retrorse anal fin. Females have large, highly distensible stomachs which give the ventral region a flabby appearance. In life, black seadevils are a dark brown to black. The skin is extremely soft and easily abraded during collection or even by simple handling. The females use their bioluminescent "fishing poles" to lure both conspecifics and prey, which include crustaceans and small fish such as lanternfish and bristlemouths; the seadevils' highly distensible stomachs also allow them to swallow prey larger than themselves, which is an important adaptation to life in the lean depths. In contrast with males, females are poor swimmers and spend most of their time motionless, waiting for something to approach their lures. Predators of black seadevils are not well known, but include lancetfish. Black seadevils Angler fish can live up to 10-15 years. Black seadevils are less than a foot long but females can weigh up to 70 lbs.

Kiwa hirsuta is an eyeless crustacean discovered in 2005 in the South Pacific Ocean. This decapod, which is approximately 15 cm long, is notable for the quantity of silky blond setae covering its pereiopods. Its discoverers dubbed it the "yeti lobster" or "yeti crab". The Yeti Crab can grow to be 5 or 6 inches long, and can weigh anywhere from 2 to ~5 pounds. Depths away from the furry legend of the Himalayas, the Yeti crab is a crustacean that dwells in deep-sea hydrothermal vents, at depths of thousands of feet. The crustaceans were found near the Pacific-Antarctic ridge, south of Easter Island, along hydrothermal vents. The bristles that cover the crab's claws and body are coated in gardens of symbiotic bacteria, which derive energy from the inorganic gases of the seeps. The crab eats the bacteria, using comb-like mouthparts to harvest them from its bristles. The yeti crab does not seem to have many predators in its natural environment; it's thought that some deep-sea octopuses and fish may find them quite edible. Unlike many other crustaceans, the females of this species carry their eggs in a specialized brooding structure on their abdomen. The eggs are attached to setae, and the female cares for them until they hatch into larvae. This method of parental care is distinctive among deep-sea organisms. This crab has is suspected to have an average lifespan of around 10-20 years. Since this species was discovered so recently research is still ongoing and we don't really know all that much about this wonderful creature.

The Greenland shark, (Somniosus microcephalus) also known as the gurry shark or grey shark, is a large shark of the family Somniosidae, closely related to the Pacific and southern sleeper sharks. This large, heavy-set shark grows to an average 8-14 feet long but can get to be 24 feet. It has a short, rounded snout, small eyes, and relatively small dorsal fins. Although it is an apex predator, it is a slow swimmer, and likely ambushes its prey and scavenges for carrion. The largest fish in the Arctic Ocean—and the only shark found there year-round—the Greenland shark also inhabits the North Atlantic and Russian high Arctic. Infrequently observed at the surface, it can live in waters 7,200 feet deep and between 28.4 to 44.6 Fahrenheit (minus 2 to 7 degrees Celsius). The Greenland shark consumes capelin, char, halibut, herring, lumpfish and salmon among other fishes. It also feeds upon marine mammals such as seals, sea lions and cetaceans. It swims at 1.22 km/h (0.76 mph), with its fastest cruising speed only reaching 2.6 km/h (1.6 mph). Because this top speed is a fraction of that of a typical seal in their diet, biologists are uncertain how the sharks are able to prey on the seals. There are no known natural predators of the mature Greenland shark, which is most likely due to its massive size. Greenland sharks are born alive (a process known as ovoviviparity) after an estimated gestation period of 8–18 years. About ten pups per litter is normal, each initially measuring some 38–42 cm (15–16+1⁄2 in) in length. Within a Greenland shark's uterus, villi serve a key function in supplying oxygen to embryos. Greenland sharks have a life expectancy of at least 272 years and could reach 392, give or take about 120 years. What's more, these slow-growing creatures don't reach reproductive age until around 150 years old. The oldest Greenland Shark found is estimated to be around 400 years old.

Idiacanthus atlanticus, the black dragonfish, is a barbeled dragonfish of the family Stomiidae, found circumglobally in southern subtropical and temperate oceans between latitudes 25°S and 60°S, at depths down to 2,000 metres. The Black Dragonfishes are long, slender fishes that are sexually dimorphic. The image shows a female with its small eyes, chin barbel, and long fang-like teeth. The male is much smaller. It lacks teeth, lacks the chin barbel, has a non-functional gut, and is dark brown rather than black. The large teeth of the dragonfish help it to grab its prey as it hunts in the dark waters of the deep sea. It will feed on small fish and crustaceans as well as anything else it can find. The black dragonfish faces danger from the red flounder fish that is found on the ocean floor. Because they live in extremely deep waters, very little is known about the mating habits of the dragonfish. It is believed that they are external spawners, meaning that the female releases eggs into the water to be fertilized by the male. The eggs then float to the surface where they remain until hatching. Once the eggs hatch, the tiny larvae are left to fend for themselves until they can reach maturity. Once mature, they return to the deep ocean to spend the rest of their lives. Not much is known about the life span of the dragonfish.

The vampire squid is a small cephalopod found throughout temperate and tropical oceans in extreme deep sea conditions. The vampire squid uses its bioluminescent organs and its unique oxygen metabolism to thrive in the parts of the ocean with the lowest concentrations of oxygen. Its huge, bright blue eyes — proportionally the largest in the animal kingdom — dark color, and the velvety, cloak-like webbing that connects its arms give the vampire squid its common name. Its scientific name, Vampyroteuthis infernalis, literally means “vampire squid of Hell”! Vampire squid are found in temperate and tropical deep-water zones worldwide at depths of 600 to 1200 m (1958 to 3937 ft). The water temperature at those depths is very cold, 2-6o C (35.6 to 42.8 o F). The vampire squid is no bloodsucker — it's a detritivore, meaning it eats dead organic material. It's the only living cephalopod species that doesn't eat live prey. What's on the menu? Mostly marine snow: particles of dead animals, rotting materials, poop, and snot. The part of the deep sea the vampire squid calls home is low in oxygen, and therefore also free of many predators. But predators exist nonetheless and include fishes, cephalopods, sea lions, sharks, and whales. Unlike most other cephalopods, a vampire squid reproduces multiple times in its life. A male vampire squid transfers his sperm to the female with his funnel (a cylindrical muscular structure found in all cephalopods used for respiration and movement). The lifespan of a vampire squid is usually very long. While the total lifespan is unknown, the adult life stage of squids can last up to eight years.

Hagfish, of the class Myxini and order Myxiniformes, are eel-shaped jawless fish. Hagfish are the only known living animals that have a skull but no vertebral column, although they do have rudimentary vertebrae. Eel-like in shape, hagfishes are scaleless, soft-skinned creatures with paired thick barbels on the end of the snout. Depending on the species, they grow to about 40 to 100 cm (16 to 40 inches) long. Primitive vertebrates, hagfishes have a tail fin (but no paired fins) and no jaws or bones. Preferring deep, soft mud habitat, hagfish are found at depths of 53 to 3,788 ft (16 to 1,155 m) (Love and Passarelli 2020) but are more common in depths less than 1,200 ft (366 m) (Love 1996). California fishermen usually catch hagfish in depths less than 1,800 ft (549 m). They prey on small invertebrates living in the mud; they also scavenge dead and dying fish. Hagfish are noted for their unusual way of feeding — they slither into dead or dying fishes and eat them from the inside out, using their "rasping tongue" to carry food into their funnel-shaped mouths. Hagfish are a popular food item for sea lions, seals, dolphins, porpoises, octopus…and people. Hagfish can be 25 to 50% of some predator's diets. Hagfish aren't as attractive as their name implies. One interesting thing about Hagfish, when threatened, can exude copious quantities of a milky and fibrous slime or mucus, from specialized slime glands. When released in seawater, the slime expands to 10,000 times its original size in 0.4 seconds. This slime that hagfish excrete has very thin fibers that make it more durable and retentive than the slime excreted by other animals. The fibers are made of proteins and also make the slime flexible. If they are caught by a predator, they can quickly release a large amount of slime to escape. If they remain captured, they can tie themselves in an overhand knot, and work their way from the head to the tail of the animal, scraping off the slime and freeing themselves from their captor. Rheological investigations showed that hagfish slime viscosity increases in elongational flow which favors gill clogging of suction feeding fish, while its viscosity decreases in shear which facilitates scraping off the slime by the travelling-knot.