221 Facts Tell Me What

Bones are hard tissues that form the skeleton in humans and other vertebrates. A bone provides a structure to an organism. Bones protect and support organs and systems, store minerals, and give mobility. In humans, at birth there are more than 270 bones. However, as development takes place some bones fuse together resulting in finally […]

The brain is an organ that is the centre of the nervous system. It is located in the skull at the top of the spinal cord. It has three main parts: the cerebellum, the cerebrum and brainstem. The cerebrum is the biggest part of the brain. The brain is the decision-maker in the body. It

Blood is a red fluid which circulates in the body of humans and other vertebrates. It carries oxygen and nutrients to cells. It also carries carbon dioxide and impurities away from cells. Heart pumps blood throughout the body in specialised vessels called arteries and veins. Blood is mainly composed of red blood cells (RBCs), white

The cell was discovered by Robert Hooke in 1665. It is the smallest living structural and functional unit. It is a microscopic body, not visible to naked eyes. A human body is composed of trillions of cells. Bacteria can be single-celled. They are of different shapes and sizes, some of them are circular, some rectangular

Cats are the members of a special family which includes tigers, lions and leopards. Cats and the other members of the family are alike in many ways. Their bodies are adapted to hunt and kill. They owe their hunting expertise to their eyes, which are adapted to see in the dark. Their eyes open wide

The word ‘amphibian’ is a Greek word that means ‘double life’. Most amphibians live both on land and in water. They begin their life in water with gills and tails. As they grow, they develop lungs and legs for their life on land. The skin of amphibians has no hair or fur. Instead, their skin

Reptiles are cold-blooded animals that have dry skin covered with scales. Most of them spend their time on land; however, some are found living in or around water bodies. All reptiles have lungs, so even those living in water must come to the surface to breathe air. Most reptiles hatch from eggs. Most reptiles are

Newts are amphibians. An amphibian is an animal that is cold-blooded and lives both on land and in water. Frogs are also amphibians. Newts look a lot like frogs, but also like fish. Newts have legs for walking just like frogs, but they also have tails for swimming like fish. Newts are also mistaken for

Dolphins are water mammals. Most dolphins are small in size but belong to whale family. They have white bellies, black backs and their tails look like half moons. They live in large herds and like to follow ships. They feed on squids, crabs, cuttlefish and various types of fish. Dolphins communicate with one another in

A sea elephant is another name of an elephant seal. Sea elephants are called ‘elephants’ because of their inflatable snouts. There are two species of elephant seals: Northern elephant seals and Southern elephant seals. Northern elephant seals live in California and Baja California, preferring to stay in offshore islands. Southern elephant seals are found in

A kangaroo rat is a seed-eating rodent which hops like a kangaroo though it is not related with it. It has a large head, large fur-lined cheek pouches, big hind legs and small front legs. It has a long tail, longer than its body and head. Kangaroo rats live in arid areas that have soft

Snakes have special glands and teeth designed to inject venom into their prey. The venom is a fluid secreted by snakes through their fangs. It is highly modified saliva containing several enzymes that attack the nervous system, blood and other tissues of the prey. Some species spit venom which helps the snake to immobilize and

There are around 135 species of antelope across the world. A gazelle is a kind of an antelope. A gazelle has a graceful body with beautiful upward-sweeping horns of different shapes. They are mostly tan-coloured with a dark side stripe on their face. They move with great speed, hence the phrase ‘as swift as a

There are around 300 species of turtles across the world. Each species possesses different food habits. Turtles are mostly carnivores. The snapping turtles are strictly carnivorous; they feed on ducks, frogs and fish under water. Green sea turtles mostly feed on marine grass and algae. The box turtle, which is a water and land creature,

The first fish appeared around 500 million years ago. In that period, after that, jawless fish came into being. During the Devonian period around 400 million years ago, all the waters of our world had fish of many different types, hence this period is also known as the ‘Age of Fish’. The jawless fish gradually