Humans are the most civilized mammals on the planet. Their co-members, found in the wilderness, are some of the most interesting creatures found on land as well as deep inside seas and oceans. There are 21 broad categories of mammals with around 5000 different species discovered to this day. All of these wild animal species, including humans, have some features common among them. They are warm-blooded, have hair-covered bodies, possess a backbone and milk their young ones.

Let's go through some fun fact about the well-developed creatures which are recorded and organized in the form of wild animals list.

• Fossil records trace mammals back to 200 million years ago, a period known as the Jurassic period.
• The biggest of all organisms existing on the planet is a mammal. It is the blue whale which can have a length of up to thirty meters and a weight of 30,000 pounds.
• The smallest of all mammals is the bumblebee bat which measures hardly an inch in length with two grams of weight.
• Other than the title of the largest organisms, mammals also win the competition for having the loudest organism of the planet in their group. It is none other than the blue whale which can produce sounds measuring 188 decibels.
• The only flying mammals are bats.
• The largest number of species of mammals is found in Indonesia. The country houses twelve percent of the total mammal population in the world.
• As the wild animals facts suggest, the fastest of all land mammals is the cheetah which can cut through the air with a speed of 60 mph. On the other hand, among water mammals, the killer whale wins the race with a speed of 34 mph.

Birds are the lovely and amazing occupants of the skies. Their ability to fly sets them apart from the rest of the creatures in the Kingdom Animalia.

Here is some interesting wild animals information regarding birds.

• Scientists have discovered more than nine thousand species of birds in the world which are put into thirty broad categories.
• The most primitive bird lived in the Jurassic period around one hundred and fifty million years back.
• Birds actually evolved from dinosaurs in the Mesozoic era. These dinosaurs are called theropods.
• Wild animals pictures cannot fully capture the skillful acrobatic postures which some birds assume. Humming birds are capable of hovering in mid-air motionless while Albatrosses create a spectacle by gliding over the sea for long distances.

These under-water creatures are found in a huge diversity. From ferocious sharks to innocent little gold fish, numerous members of this group can be found in the aquatic environment.

Fish have the following interesting facts about them.

• There are three main categories of fish, namely, bony fish, lobe-finned fish and cartilaginous fish.
• The first creatures to have developed backbones were fish.
• The largest group (category) of fish with the greatest number of species is the ray-finned fish. There are more than twenty-four thousand species of this particular fish found in the waters.
• These water creatures swim forward through wave motions of the water which provide a forward thrust to them.
• The Whale Shark is the biggest fish in the world. It has the length of up to 65 feet with 75, 000 pounds of weight. This makes it heavier than the Blue Whale which is the world's largest organism.

These creatures occupy both land as well the waters since they can survive in both. Mostly, the life of amphibians begins in water and they move towards the land as they mature. Toads, frogs and salamander are the most common amphibians known to most people.

Update your knowledge about amphibians through these interesting facts.

• Amphibians first appeared on the planet around three hundred and seventy million years ago in the Devonian period.
• Today, scientists have discovered around 6,000 species of amphibians.
• All the amphibians are divided into three main groups: toads and frogs, caecilians and salamanders and newts.
• The first vertebrates with four limbs to appear on the earth were amphibians.
• The skin of these organisms is very delicate with no protection of scales.
• Their skin always remains moist due to the presence of numerous mucous glands.
• Beware! Do not touch an amphibian with bare hands. Along with mucous, their skin also produces poisons some of which can be toxic to the extent of being lethal.
• The largest of all amphibians is called the Chinese Giant Salamander. It can grow up to six feet in length.

With snakes, crocodiles and poisonous lizards, the group of reptiles is not a pleasant one. However, some innocent and cute creatures, such as turtles, are also found in this group. Reptiles are distinguished due to their hard and scaly skin. They are also cold-blooded and lay eggs with hard shells.

Discover some interesting facts about reptiles here.

• Reptiles have evolved from amphibians. This phenomenon took place around 340 million years back.
• Over eight thousand species of reptiles are found crawling across different parts of the world.
• Reptiles occupy the entire earth except Antarctica. Not even a single of these cold-blooded creatures is found on this extremely cold continent.
• Mammals might have won the title of the largest and the loudest organism, but reptiles are the lucky creatures with the longest life span. The Aldabra tortoise can live up to 200 years.
• Although snakes are the most formidable reptiles giving us goose bumps just at their thought, only two percent of all the snake species in the world are harmful to human beings.
• Among the largest of all reptiles are the Komodo Dragon, the leatherback turtle and saltwater crocodile.

The wildlife is, indeed, extremely diverse with lots of species and facts still undiscovered. All the knowledge we do have about it is extremely intriguing and insufficient.