The Indian Crested Porcupine is a nocturnal mammal in southern Asia and the Middle East. It has long, thin quills on its head and back, which it raises when threatened. Moreover, it can adapt well to various environments, including rocky hillsides and sandy deserts.

During the day, the Indian Crested Porcupine stays in its burrow. Then, it ventures out at night to forage. The porcupine feeds on roots, fruits, and crops. It also gathers bones to supplement its diet with essential minerals.

A study on Indian Crested Porcupine's quills reveals the development of antibacterial keratin microparticles1. These microparticles enhance pharmacological action against harmful bacteria, like Escherichia coli and Staphylococcus aureus, showing up to a 55% improvement when coated with lipids from the same quills. This groundbreaking study demonstrates potential use in clinical applications.

The Malayan Porcupine lives in the dense forests of Southeast Asia. During the day, it hides in the root networks of trees, termite mounds, or rocky crevices. At night, it emerges to feed on roots, bark, and fallen fruits. 

Moreover, the Malayan Porcupine's most distinctive feature is its coat of sharp, dark quills that stand on end when it senses danger. It also occasionally preys on insects or small vertebrates.

The Cape Porcupine has black quills with white or yellowish stripes, a crucial defense mechanism. It lives in a wide range of habitats across Africa. 

While primarily an herbivore, Cape Porcupines also gnaw on bones to supplement their diet with calcium. They are also good swimmers and climbers.

The Philippine porcupine, also known as the Palawan porcupine, is a distinctive creature native to the island of Palawan in the Philippines. Its habitat is commonly a blend of secondary forest and grassland, with some residing in lowland primary and secondary forests. 

IUCN gave Philippine Porcupines vulnerable status2. Over the coming 22 years, its population is projected to decrease by more than 30%. Forest loss and its rampant use in pet and bushmeat trade are significant factors accelerating this decline.

The African brush-tailed porcupine  (Atherurus africanus) is a species of rat-like Old World porcupine, indigenous to a broad belt of Africa ranging from Guinea on the west coast to Kenya on the east. This is a common species with a very wide range, and despite it being used extensively for bushmeat, the International Union for Conservation of Nature  has rated its conservation status as being of "least concern".[1]

The American Eel lives in the far-flung corners of the North Atlantic. It has a snakelike body and can grow up to five feet, though most individuals measure only two to three feet. 

Its skin ranges from yellow to green-brown, and it has a lighter belly, camouflaging it in riverbeds and coastal waters.

These types of eels are both freshwater and saltwater eels. They spend most of their lives in freshwater or brackish environments. However, during the breeding season, they migrate to the ocean. 

Additionally, these true eels eat various prey, such as insects, crustaceans, and fish. At night, the American eel emerges from the sand to hunt. They also don’t hesitate to step onto land for food.

The European Eel can grow up to 5 feet long and camouflage itself in its environment. Moreover, they are nocturnal hunters that feed on insects, crustaceans, mollusks, and other small aquatic animals.

Additionally, European Eels are catadromous; they spend most of their lives in freshwater or brackish waters and travel to the Sargasso Sea to breed1. 

They turn from larvae to glass eels during their journey, then to yellow and silver eels. These types of eels can also breathe through their skin, enabling them to survive short periods of drought.

The Japanese Eel lives off the coast of Japan, Korea, Vietnam, and the northern regions of the South China Sea. They are olive green, tranquil brown, white, or soft yellow. Moreover, they have small heads with large eyes that help them see in the dark.

The Japanese Eel migrates most of its time in freshwater or brackish waters. During the breeding season, they migrate into the ocean, swimming hundreds, or even thousands, of miles to reach spawning grounds in the far West of the North Pacific Ocean.

Part of the eel life cycle is the development of leptocephali, offspring that rely on ocean currents to guide them back to their freshwater habitats for several months3.

The mottled eel (Anguilla bengalensis), also known as the African mottled eel, the Indian longfin eel, the Indian mottled eel, the long-finned eel or the river eel is a demersal, catadromous eel in the family Anguillidae. It was described by John McClelland in 1844. It is a tropical, freshwater eel which is known from East Africa, Bangladesh, Andaman Islands, Mozambique, Malawi, Sri Lanka, Sumatra, and Indonesia and recently from Madagascar. The eels spend most of their lives in freshwater at a depth range of 3–10 metres, but migrate to the Indian Ocean to breed. Males can reach a maximum total length of 121 centimetres and a maximum weight of 7,000 grams. The eels feed primarily off of benthic crustaceans, mollusks, finfish and worms.

The Indonesian Shortfin Eel is a deep-brown to light-yellow eel that inhabits the Indian Ocean, Western Pacific Ocean, and Indonesian waters. It is a unique subspecies of the Shortfin Eel, characterized by its shorter dorsal fin beyond the pectoral fins. This catadromous eel lives in freshwater rivers and streams.

During the breeding season, these eels swim against the current and return to the ocean. Moreover, the Indonesian Shortfin Eel embarks on land excursions, using its slender body and sharp pectoral fins to explore new territories. They undertake these journeys at night when they emerge from their burrows and crevices.

Scanning their surroundings for prey, they mainly feed on small fish, crustaceans, and other invertebrates.