1. Ostrich
2. Horse

Though ostriches only have two toes on each foot, they are the fastest birds on land. This flightless bird has an amazing speed of 40 miles per hour and can even outrun a horse!

1. Clownfish
2. Red sea urchin

The red sea urchin is a small marine animal with a surprising lifespan. It can live up to 30 years old, which is much longer than the clownfish, which has a lifespan of 6 to 10 years in the wild.

1. Gorilla
2. Dog

The evolution theory concerning humans and monkeys has existed for decades and probably won't die out anytime soon. Scientists have found that these furry animals have a lot in common with us, including the ability to contract diseases like scabies, influenza, diarrhea and even tuberculosis.

1. Lioness
2. Lion

When it is time to hunt for food, lions and lionesses defy the traditional gender roles. The lioness is the active hunter that stalks its prey before attacking, while her male counterpart protects the pride.

1. Reindeer
2. Camel

After a brief mating season of about two months, the pregnant camel will carry its young for about 13 to 15 months before it gives birth. This is even longer than a reindeer, which has a gestation period of 200 to 220 days.

1. Emperor penguin
2. Dolphin

During the cold winter season in Antarctica, the male emperor penguin incubates its egg while the female goes hunting. He does not eat during this entire period and can survive up to 120 days without food.

1. Angel shark
2. Manta ray

Due to overfishing, the angel shark is one of the rarest animals of the marine world. It is believed that there are only a few thousand left of this endangered animal, which is usually found in temperate and tropical seas worldwide.

1. Koi
2. Tetra

Koi is a colorful fish that was bred by the Japanese in the 19th century as a variation of the common carp. The average Koi can live up to 40 to 50 years, but there are Koi fish that many believed to have lived over 100 years.

1. Dolphin
2. Beaver

Beavers split their time between land and sea, and they are equipped with bodies adapted to their lifestyle. In addition to their webbed feet, this large rodent can also hold its breath underwater for 15 minutes at a time.

1. Prairie dog
2. Rabbit

Rabbits are not just cute animals, they're also very fertile too. After a month-long gestation, they can birth 1 to 14 kits and can become pregnant again moments after. During their seven-year lifespan, they can birth hundreds of babies.

1. Sheep
2. Goat

Sheep are docile animals that are found in many countries all over the world. Their population exceeds one billion worldwide, and nineteen percent of this population has been found in Asia and Africa.

1. Crocodile
2. Sawfish

The subtropical sawfish was placed on the list of endangered animals in 2003. Sawfish populations have declined by over 80 percent, with the large tooth sawfish under major threat of extinction.

1. Grizzly bear
2. Springbok

Springbok, the South African antelope, has a speed of 55 miles per hour. This is much faster than the grizzly bear which can only run 35 miles per hour.

1. Humans
2. Greater bilby

The greater bilby is a marsupial from Australia. This small animal's survival depends on hot, dry climates.

1. Sperm whale
2. Killer whale

The sperm whale is not only the largest toothed whale, but it also has the largest brain ever seen! Its brain is larger than that of a killer whale and weighs five times that of a human.

1. Wolves
2. Snakes

Since the beginning of time, snakes have been a major threat to human life. The inland taipan is one of the most poisonous creatures, while the saw-scaled viper contributes to the majority of human deaths yearly.

1. Dog
2. Turkey

There is a reason dogs are used in therapy: they are incredibly smart animals. Dogs are believed to be as smart as a toddler, with the ability to interpret over a hundred gestures and words.

1. Antelope
2. Spotted deer

The Visayan spotted deer is an endangered species native to the Philippines. Its rarity is most likely due to hunting and destruction of habitat.

1. Sunfish
2. Seahorse

The ocean sunfish is a large animal known for many things, such as its ability to release 300 million eggs at once. This is after spawning for several months, usually from August to October.

1. Macaw
2. Bald eagle

Macaws are brightly shaded birds that generally live up to 60 years. However, it has been reported that gold and blue macaws have lived over 100 years in captivity.

1. Grasshopper
2. Gazelle

A grasshopper's back legs act like catapults, propelling it up to 30 inches. A grasshopper can also fly.

1. Human
2. Cat

Cats are not just adorable creatures; their bodies are amazing too! They have 32 muscles in each ear, which is many more than what we humans have.

1. Scorpion
2. Box jellyfish

The box jellyfish has rightfully earned the title of one of the most poisonous marine animals. Its powerful venom can instantly kill its prey or send a healthy human into shock or heart failure.

1. Sharks
2. Dinosaurs

Sharks are apex predators that have been on the Earth for a very long time - over 450 million years. They have outlived dinosaurs and survived the Cretaceous-Tertiary extinction.

1. Gazelle
2. Cheetah

Cheetahs are large cats found on the vast continent of Africa. They are recognized as the fastest land animal, with a speed of up to 64 miles per hour.

1. Spider
2. Butterfly

Butterflies are colorful insects equipped with 12,000 eyes. They are near-sighted creatures, but they can see ultraviolet colors that humans cannot.

1. Lion
2. African elephant

African elephants are the world's largest land mammal, and can live for about 60 to 70 years. Lions, on the other hand, can live for 10 to 14 years.

1. Walrus
2. Manatee

Of all the animals in the pinniped group, walruses have the longest pregnancy. Their cycle lasts for about 15 to 16 months before they give birth to their young.

1. White lion
2. Tiger

In 1938, the earliest recorded sighting of the white lion was made in the Timbavati region of South Africa. The tiger is much more commonly sighted in comparison to the white lion, which is hunted and killed for its unique fur.

1. Bottlenose dolphin
2. Sperm whale

The sperm whale is a fierce predator that can spend 90 minutes underwater before emerging for air. This is much longer than other marine animals, such as the bottlenose dolphin, which can only remain submerged for about 12 minutes.

1. Wild ass
2. Chicken

Animals such as the wild ass are able to endure the harshest of temperatures. The wild ass survives in Dallol, Ethiopia, where temperatures spike to 120 degrees in summer.

1. Platypus
2. Starfish

Starfish have the uncanny ability to turn their stomach inside out to capture their prey. The stomach covers the prey and partially digests it before the starfish pulls it back into its body.

1. Lion
2. Coyote

Lions are speedy animals that can move as fast as 50 miles per hour. This is even faster than the coyote, which has a top speed of 43 mph.

1. Tiger
2. Armadillo

The nine-banded armadillo produces four identical quadruplets from a single fertilized egg that has split. It is the only mammal known for this ability.

1. Human
2. Whale

The expected heart rate of a human is 60 to 100 beats per minutes in adults and 70 to 100 for children under 15 years of age. Age and physical health are some factors which can influence heart rate.

1. Bowhead whale
2. Dolphin

The bowhead whale has gone down in history as the mammal that has the longest lifespan - over 200 years. They also don't suffer from cancer and other diseases humans do.

1. Turtle
2. Coral

Once a year, thousands of eggs from coral polyps are released into the water for external fertilization. Countless polyps participate in this mass reproduction.

1. Owl
2. Swan

Swans are beautiful aquatic animals with more than 25,000 feathers. Seventy percent of these feathers are on its head and neck.

1. Fox
2. Snow leopard

The snow leopard is one of the rarest big cats on the planet. This leopard inhabits the stony mountains of Central Asia, and it is believed that there are only 10,000 of them in the wild.

1. Mosquito
2. Crocodile

Though tiny by nature, mosquitoes are dangerous! The World Health Organization estimates that mosquitoes are responsible for 725,000 deaths yearly. This is due to the many diseases they carry, such as malaria and dengue.