The Hellbender is the largest aquatic salamander in North America. This species has adapted to the fast-flowing rocky rivers and streams in the Eastern United States, which it navigates easily due to its unique body shape. Its flattened body can reach up to 29 inches long. 

The Hellbender hides under rocks during the day and comes out to hunt for food at night. Its diet mainly consists of crayfish, but can also eat small fish, insects, and other salamanders. 

Moreover, its blotchy brown skin provides excellent camouflage against the riverbed. It is covered in a slimy mucus that acts as a respiratory organ, allowing the salamander to absorb oxygen directly from the water.

The Chinese Giant Salamander is the world's largest amphibian, found in the streams and lakes of China. It can stretch up to almost 6 feet in length, second only to the largest amphibian which is discussed in the next section. 

They are active at night and feed on insects, frogs, crabs, and fish. Sometimes, they resort to cannibalism. Since they have poor eyesight, they have a built-in vibrational sensor called the lateral line system that helps them locate prey and avoid danger. 

Interestingly, they make sounds resembling a baby crying, so locals in China call them "baby fish.” Despite this endearing name and their huge size, Chinese Giant Salamanders have the IUCN Critically Endangered status due to habitat destruction and overhunting7.

The Japanese Giant Salamander lives in Japan's mountainous landscapes. Its crinkled and coarse skin helps it blend in with the rocks in its watery habitat. Like other salamanders in the Andrias genus, it is large, reaching up to 5 feet.

These types of salamanders are nocturnal creatures that rely on their sense of smell and touch to hunt for fish, insects, worms, and small mammals. During the breeding season, males become aggressive and fiercely guard their nesting sites, which can hold up to 500 eggs.

The Persian Mountain Salamander inhabits the temperate rainforests at the southwestern rim of Iran's Caspian Sea. It has a rectangular head and rounded tail, typically longer than the rest of its body.

These Asiatic salamanders sport a dark hue speckled with irregular yellow spots. These salamanders present carnivorous traits throughout their lives, feasting on arthropods and other small animals within their shared environment.

Tiger Salamanders are mole salamanders that can reach up to 14 inches long. It has dark skin with bright yellow or olive-colored blotches and is found in various habitats across North America.

Native tiger salamanders are reported in the northern and eastern U.S. and are regarded as relict populations. Conversely, the west coast hosts non-native species, resulting from using larval salamanders as fishing bait4, causing hybridization.

They spend their days concealed in burrows, under rocks or logs, emerging only at night. Their diet includes invertebrates such as worms, insects, slugs, and sometimes even small mammals, reptiles, or amphibians. 

During the spring mating season, males deposit a spermatophore on the ground, which females use to fertilize their eggs. Most salamander species use this reproductive method. Afterward, the fertilized eggs attach to vegetation in shallow bodies of water, and the larvae transform into terrestrial adults over the next few months.

The Spotted Salamander, also called Yellow-spotted Salamander, lives in the forests of eastern North America. Their yellow or orange spots warn predators of their toxicity and help them blend in with the forest floor. 

Moreover, they are active at night, eating insects and other invertebrates, which helps keep pest populations in check. They mostly live underground and will come out to eat or breed.

The Marbled Salamander is a visually appealing species inhabiting the deciduous forests in the eastern United States. This species demonstrates sexual dimorphism - females typically showcase light grey bands, while males present strikingly white ones.

They live near bodies of water, frequently burrowing under rocks or logs. When threatened, they curl their tails to expose their bright underside, secreting a mild toxin. Other defense mechanisms include the coiling of bodies and the lashing of tails.

Axolotls are critically endangered salamanders living in the lakes and canals around Xochimilco in Mexico. Unlike most salamanders, they are neotenic, which means they spend their entire lives in larval form. 

Axolotls have a distinctive silhouette, broad heads, lidless eyes, finned tails, and external gills. Wild axolotls sport dark tones, while leucistic varieties have a pale or golden coloration.

The California Tiger Salamander is endemic to California's grasslands and vernal pools. It is one of the largest species in its family, growing to 7-8 inches. 

Since they are mole salamanders, they spend most of their lives in burrows and migrate to temporary pools during the rainy season to lay their eggs. The larvae remain underwater for a few months until they transform into land-dwelling adults. 

Their diet consists of small invertebrates, and they have a unique defense mechanism when threatened. They also regulate the insect population in their ecosystem.

The Pacific Giant Salamander, a large species endemic to the Pacific Northwest in North America, can grow up to 13.4 inches. It typically has dark brown to black backs, adorned by light brown spots or marbling, and lighter underbellies.

This salamander prefers semi-aquatic habitats, favoring small-to-mid-sized streams and riverside forests.

Pacific Giant Salamanders get vocal if disturbed, emitting a distinct "bark." Adopting a defensive pose, it arches its body, thrashes its tail, and when the need arises, repels predators by secreting a noxious substance. Adults can also head-butt and bite.