The West Indian Fuzzy Chiton mainly lives from southern Florida to Panama, including Mexico and the West Indies. It thrives on high-intertidal rocks, enduring harsh and variable conditions.

This type of mollusk doesn't grow beyond 2.8 inches in length. Spiky and banded with various hues of black, its girdle encloses the creature's plates, acting as an exterior armor.

Now, the shell of chitons typically comprises eight distinct plates. The West Indian Fuzzy Chiton, though, presents an anomaly. It boasts a fifth valve, split into two symmetrical halves. These halves function independently from the other, separated by a griddle-like tissue.

The Common Hippopotamus, or the River Hippopotamus, dominates the African landscape, ruling sub-Saharan Africa's lakes, rivers, and mangrove swamps. 

A male hippo can reach 3,260 lb. Despite its massive size, it is surprisingly fast, reaching up to 22 miles per hour on land on short distances. 

One of its most distinctive characteristics is the secretion of "blood sweat," which acts as a natural sunscreen and antibacterial agent. 

Male hippos reach maturity at 7.5 years old, while cows are 5 to 6 years old. After an eight-month gestation period, a female hippo isolates herself from the group. It gives birth to one calf on land or in shallow water. 

Interestingly, calves fold their ears and close their nostrils as they nurse on female hippos underwater. Moreover, this nocturnal herbivore can consume around 80 pounds of grass overnight. Adults have no known natural predators, but lions, hyenas, and crocodiles endanger young hippos.

Despite their formidable size, Common Hippos are not sociable. While they form groups, they do so primarily for protection rather than companionship.

The hippos are a vulnerable species, facing a population decline due to poaching and civil unrest1. Elephant ivory substitutes, such as hippo teeth, heighten demand in illegal markets. Conservation efforts are vital, yielding slight improvements in protected areas.

Here are five subspecies of the common hippo with differences in their skulls and geographic ranges

The Pygmy Hippopotamus is native to the dense forests and marshy swamps of West Africa. Unlike its larger relative, it is only half its height and weighs only a fraction. It measures 69 inches long and stands 39 inches tall at the shoulder. 

Moreover, the pygmy hippo lives in the water more than on land. While these animals weigh up to 606 pounds, they move with the grace and agility of a jungle ballerina.

This solitary creature spends the day hidden in cool rivers or wallows, venturing only at night to forage for food. It eats ferns, broad-leaved plants, grasses, fruits, small insects, and worms. 

Pygmy hippos are facing declining numbers due to habitat destruction from commercial plantations2, mining, and shifting agriculture. Intensified bushmeat hunting exacerbates their plight, warranting their endangered status. With fewer than 2,500 mature individuals, a 20% population decrease over two generations is projected.

The North American Porcupine, or Canadian Porcupine, is the largest porcupine species in North America. It is distributed across various habitats and can reach three feet with tails up to a foot long.

It has around 30,000 barbed, hollow quills embedded into its skin or hair and can easily detach from the porcupine's body. Additionally, North American Porcupines feed on various vegetation, making it a nuisance to foresters. Predators like the North American golden eagles also hunt them.

One peculiar habit of the porcupine is self-anointing, which involves creating a paste and meticulously applying it to its quills. Scientists still do not know the reason behind this behavior.

The Brazilian Porcupine is a highly adaptable creature found in various habitats in South America. It sports short, thick, whitish, or yellowish spines, darker hair, and a gray underside. Its fleshy lips and nose complement its prehensile tail, which curls upward to grip tree branches.

This nocturnal animal spends most of its time high up in tree canopies, using its prehensile tail to climb quickly. Moreover, the Brazilian Porcupine raises and shakes its quills and may drive its sharp quills into their predators’ skin. These New World porcupines eat bark, leaves, and fruits, particularly mangoes and avocados.

The Bristle-spined Porcupine is an arboreal rodent from the Atlantic forests of Eastern Brazil. Its key identifying feature is the unique texture of the spines on its back, which feel more like bristles than traditional spines.

Its unique anatomy has special traits like a bony ring around the eye socket and unusually narrow incisors. This rodent exhibits a mix of cranial features seen in other rodents, creating a distinct profile.

Unfortunately, Bristle-spined Porcupines are vulnerable species. Only 17% of their natural habitat remains intact. Forest fragmentation and habitat quality decline are also contributors.

The Thin-spined Porcupine lives in the Atlantic Forest of Brazil, spending its daylight hours in hollows. It is primarily nocturnal and feeds on leaves; cecropia tree foliage is a favorite. It faces various predators, including wild cats, large birds of prey, and humans who hunt it for its meat and spines. 

They are primarily brown or grey, boasting bristle-like hairs rather than typical spines. However, the head, neck, and forelimbs feature less pliable spiky hairs. Their feet and tail exhibit a dark brown or black hue.

Moreover, their breeding season is not specific. Female porcupines give birth to one offspring after a gestation period of around 210 days.

The Streaked Dwarf Porcupine is a New World porcupine discovered in Ecuador and Peru in 2001. This porcupine type stands out due to its long tail, almost hairless adult body, darker quill tips, and three-colored barbed hairs. Its belly is unusually spiky and bears a unique set of skull features.

The Roosmalen's Dwarf Porcupine inhabits the southern Amazon rainforest in Brazil. Dutch botanist and ecologist Marc van Roosmalen discovered it in 2001. 

Roosmalen's Dwarf Porcupine is smaller than other porcupine species, weighing only about 2 pounds as an adult. Its shorter quills are less dense and have bands of black and white. Additionally, its prehensile tails help it navigate through dense trees. 

This nocturnal species spends its days in the safety of hollow trees or burrows. It ventures out at night to forage for food. Its diet consists of leaves, fruits, and bark, with a preference for certain palm fruits.

Their reproduction is slow, and they give birth only to a single offspring after a gestation period of about seven months.

The Black-tailed Hairy Dwarf Porcupine lives in the rainforests of Colombia and Venezuela. It has a black tail with dense and short quills, which it uses for defense. It has a prehensile tail and spends its days in the safety of the tree canopy. 

This porcupine also feeds on leaves, fruits, and small branches and gives birth to a single offspring after carrying it for about 202 days.