1. Spiders
   Cockroaches
2. Snakes
   Centipedes

There are over 4,000 different kinds of cockroaches, which means there are quite a few intrusions around the world. If you are one of the many people who find these little bugs terrifying, then you have katsaridaphobia.

1. Bats
   Frogs
2. Lizards
   Worms

Bats are nocturnal animals and the only mammals capable of sustaining flight instead of gliding like a flying squirrel to travel through the air. While flight speed varies with the species, some can reach over 100 mph.

1. Giraffes
   Tigers
2. Zebras
   Elephants

African elephants are the world’s largest land mammals. Elephants' tusks never stop growing (except for female Asian elephants, who usually don’t have tusks). This means the bigger the tusks, the better the indication that you’ve spotted an older elephant.

1. Bobcat
   Lemur
2. Chimpanzee
   Galago

Lemurs are very social creatures, so they’d mostly be found living together, which can also help when they're faced with a predator. The only places in the world with natural lemur populations are the islands of Madagascar and Comoro, off the coast of Africa.

1. Snakes
   Lions
2. Bears
   Slugs

There are many different species of bears — these mammals are diverse and have adapted to living in various climates all over the world. The polar bear is the only true carnivorous bear, as most of the others are omnivores, eating both plants and animals. Of course, there's also the giant panda, which pretty much focuses on bamboo.

1. Foxes
   Alligators
2. Leopards
   Horses

A leash of foxes is a more uncommon sight than just one, as foxes usually prefer a life of solitude. Luckily, foxes have unique methods for getting around, such as using the whiskers on both their legs and faces to navigate.

1. Chickens
   Dragonflies
2. Parakeets
   Crows

Crows are extremely intelligent and have even been seen using tools, such as sticks, to access meals that are slightly out of reach. These birds also have an amazing memory, especially regarding food, hiding it away without fear of forgetting where they’ve put it.

1. Squirrels
   Badgers
2. Rhinoceroses
   Moose

It’s no wonder where these animals got their name, as the word “rhinoceros” means “nose horn,” for which they are sadly often hunted. A rhino’s horn is made up of keratin, the same protein found in human fingernails and hair.

1. Tarantulas
   Squids
2. Hermit crabs
   Lobsters

A squid’s skin gives it the ability to change color, which can help when it needs to camouflage from predators. Speaking of protecting itself, a squid squirts ink to cloak itself in a dark cloud, difficult for other creatures to see.

1. Hedgehogs
   Porcupines
2. Sea urchins
   Caterpillars

On average, a porcupine’s body is covered with approximately 30,000 quills. Whenever the animal feels threatened, it will bristle, making its quills more prominent and dangerous. Porcupines don’t shoot their quills, as was once believed.

1. Crocodiles
   Iguanas
2. Geckos
   Komodo dragons

Crocodiles are the biggest living reptiles on the planet, and they are found on every continent other than Europe and Antarctica. Their size doesn’t mean they can’t be sensitive, though, as they’ve been known to shed a few "crocodile tears" (which often happens whenever they snort while eating).

1. Flies
   Bees
2. Crickets
   Cicadas

A fly does not have any teeth and instead uses its long tongue-like proboscis as a straw to suck up food. A female fly will often lay eggs on its food. There are more than 100,000 species of flies all over the world.

1. Peacocks
   Parrots
2. Toucans
   Flamingos

A flamingo’s pretty pink color is all thanks to its diet. The crustaceans, plankton and algae they eat are chock-full of beta carotene, which is why flamingos will turn gray if they aren’t fed their healthy, natural diet of such marine animals.

1. Eels
   Octopuses
2. Sharks
   Barracudas

Sharks have many teeth, growing in multiple rows, and each sheds thousands over a lifetime. Sharks are commonly feared, though they aren’t as dangerous as you may think – hippos, deer and even cows are known to cause more human deaths than sharks.

1. Tigers
   Wolves
2. Cougars
   Ocelots

Tigers are the largest species within the feline family — other than ligers, which are the result of crossbreeding by man. Some tigers grow as long as 11 feet from head to tail and weigh over 600 pounds. Sadly, there are more tigers living in captivity than in the wild.

1. Pigeons
   Partridges
2. Doves
   Emus

Partridges lay more eggs on average than any other bird. Their nests are often crowded with 15 eggs at a time, though even larger numbers have been recorded. A young partridge is able to fly properly at just 15 days old.

1. Orangutans
   Wildebeests
2. Woodpeckers
   Hyenas

A group of hyenas is called a cackle or a clan. Female hyenas are bigger and hold more dominance than males. Hyenas use various signals to communicate, including sounds and postures. A hyena’s laugh is actually a way to alert others within the cackle of a new food source or a threat.

1. Dogs
   Bearded dragons
2. Hamsters
   Cats

Cats are one of the most beloved pets — there are over 500 million domestic cats in the world. While kittens are commonly known as a litter, a group of cats can go by a variety of names, including a clutter, a pounce, a nuisance, a glorying or a glare.

1. Giraffes
   Horses
2. Antelopes
   Hippos

A giraffe is the tallest living mammal on the planet, with its legs alone at a height of six feet on average. Their size doesn’t limit their speed, though, as a giraffe can sprint as fast as 35 mph over a short distance.

1. Rabbits
   Gerbils
2. Toads
   Kangaroos

Toads are like frogs, in the sense that they start as tadpoles, though once grown they are able to live farther away from water. Toads do not have teeth. Instead of chewing, these animals swallow their food whole. Talk about a mouthful!

1. Buffalos
   Whales
2. Deer
   Polar bears

Buffalos found in North America are known as "bison," and they are the largest land animals in this region. Buffalos are known for having a giant hump, which is made up of muscles and vertebrae, helping the animals travel through snow.

1. Dolphins
   Seals
2. Seahorses
   Penguins

As flightless birds, penguins rely on aquatic traveling. The animals are able to navigate through water thanks to adapted flippers, which help them swim. Emperor penguins can remain underwater for about 20 minutes at a time.

1. Ants
   Fireflies
2. Caterpillars
   Ladybugs

A caterpillar has 12 eyes (half a dozen on each side of its head), though this doesn’t equate to good eyesight. The eyes, known as "stemmata," are solely used to differentiate between light and dark.

1. Trout
   Raccoons
2. Llamas
   Rats

Trout spend the majority of their time eating, dedicating a whopping 80% of any average day to searching for food. Larger trout are capable of eating larger prey, with even some in New Zealand known to feast on mice.

1. Cobras
   Jaguars
2. Turtles
   Gorillas

Jaguars hunt on both land and in water, making these large cats very versatile predators. It’s easy to see how the word "jaguar" came from the Native American word "yaguar," which means “he who kills with one leap.”

1. Jellyfish
   Shrimp
2. Clam
   Flounder

A jellyfish doesn’t have a brain, heart, bones or eyes. When hunting for food, a jellyfish uses its tentacles to sting (and sometimes even paralyze) prey before leading the meal towards its mouth, which is located in the center of its body.

1. Manatees
   Grizzly bears
2. Otters
   Elk

The sea otter is known for having the thickest fur in the entire animal kingdom. A single square inch of its body can be covered in as much as one million hairs. An otter has two layers of fur, which trap air and keep the animal dry, warm and even buoyant.

1. Sparrows
   Ducks
2. Geese
   Turkeys

Turkeys may be known for the iconic gobbling sound they make, but only the males do this. Males make this noise to attract females and warn rival males. Both males and females communicate via purrs, whistles, cackles and yelps.

1. Wombats
   Echidnas
2. Possums
   Koalas

Wombats are marsupials, meaning the female animal gives birth to a baby that soon heads into its mother’s pouch to finish developing. The opening of a wombat’s pouch faces the rear instead of the head so it can dig without getting dirt inside.

1. Pandas
   Snow leopards
2. Zebras
   Skunks

Each zebra has a unique pattern of black and white stripes, which many experts believe function as camouflage, since their main predator, the lion, is colorblind. When they're being chased by a predator, zebras will run from side to side in an attempt to get away.

1. Ants
   Badgers
2. Worms
   Moles

Moles burrow in the ground, digging tunnels and houses using their shovel-like curved front paws and claws. Their favorite food is worms, and just one mole can consume more than 50 pounds of worms in a year.

1. Parrots
   Cockatoos
2. Parakeets
   Canaries

Most of these colorful birds spend their lives in tropical areas, feeding on seeds, fruit, nectar, flowers and small insects. There are more than 370 species of parrots around the world, and some can live to be over 80 years old.

1. Wasps
   Grasshoppers
2. Beetles
   Moths

A grasshopper's legs function like catapults, enabling it to jump nearly 10 inches high and nearly three feet in distance. This would be relative to a human leaping the length of a football field.

1. Pigs
   Goats
2. Sheep
   Chickens

Goats were among the first animals to be domesticated, nearly 11,000 years ago. Goats have wide rectangular pupils, which give them a better range of vision than animals with round pupils.

1. Tortoises
   Oysters
2. Snails
   Crabs

Depending on the species, snails may live as long as 25 years. The snail is known to be one of the slowest animals on the planet, with a common garden snail’s peak speed at just 50 yards per hour. Talk about a snail’s pace!