Category Zoology

Which sea mammal can swim the fastest?

The fastest sea mammal in the world is the killer whale. With its streamlined body and powerful tail, it can speed through the water at up to 55 kph. That’s more than six times faster than the quickest human swimmers.

Is it true? Spinner dolphins spin like tops in the air.

Yes. Spinner dolphins are easy to recognize. They can leap out of the water, high into the air, and then spin around quickly like tops. These amazing acrobats live near the coast in warm seas.

Which is the speediest seal?

The fastest seal in the sea is the California sea lion, with a top speed of 40 kph. The fastest on land is the crabeater seal, reaching 19 kph over snow and ice.

Amazing! Some sea mammals can hold their breath for almost two hours before they have to come to the surface for air. Most humans can only hold their breath for a minute or so.

What is one of the deepest divers?

Sperm whales dive over two kilometres after their food. One sperm whale was even found with two deep-sea sharks in its stomach. It must have dived to three kilometres to catch them.

Picture Credit : Google

What do walruses use their tusks for?

A walrus uses its long tusks to chip shellfish from rocks and break breathing holes in the ice. The males also use their tusks to fight off rivals and attract a mate.

Which seal blows up balloons?

To attract a mate or scare off a rival, a male hooded seal blows air into its nose! It can inflate the lining of one of its nostrils so that it looks like a big, red balloon.

Is it true? Seals cry when they are sad.

No. Seals sometimes look as if they’re crying, but it’s not because they’re sad. The tears keep their eyes moist and clean. In the sea, they get washed away. On land, they trickle down their cheeks.

Which seals live at the ends of the Earth?

Weddell seals live in the far south, on ice-covered islands off the coast of freezing Antarctica. Ringed seals live in the Arctic, at the other end of the world. They’ve been found as far north as the North Pole.

Amazing! In hot weather, some seals and sealions flip tiny pebbles and sand on to their backs with their flippers. This helps to keep them cool, and it also scratches them if their skin is feeling itchy.

Picture Credit : Google

What are sea mammals?

Sea mammals spend most of their lives in or near the sea. There are three groups of sea mammals. Whales and dolphins are called cetaceans. Seals and walruses are called pinnipeds. Manatees and dugongs are called sirenians.

Amazing! There are well over 10 million crabeater seals living in the icy Antarctic. Seals are found in many parts of the world, but the southern crabeaters are the most common type of seal on Earth.

Which special features help whales live in the sea?

A whale’s body is designed for swimming. It has a smooth, streamlined shape for pushing through the water, and blowholes for breathing on top of its head.

Which is the biggest sea mammal?

The huge blue whale is the biggest mammal in the sea. In fact, it’s the biggest animal that has ever lived. It can grow more than 30 metres long and weigh as much as 130 tonnes.

Is it true? Whales once lived on land.

Yes. The ancestors of today’s whales once lived on land. About 50 million years ago, they went into the sea to look for food and their bodies adapted to life in the water.

Picture Credit : Google

Do all whales have teeth?

Some whales have long, tough bristles, called baleen, hanging down inside their mouths, instead of teeth. They don’t chew their food, but sieve it from the water through the baleen.

Amazing! Whales have a thick layer of fat, called blubber under their skins. This keeps them warm in the cold sea. At about 50 centimetres, the bowhead whale has the thickest blubber.

Is it true? A whale uses its blowhole as a nose.

Yes. Like all mammals, whales must breathe air to stay alive. Instead of nostrils, they have a blowhole on top of the head.

What has tiny shellfish on its back?

Some whales have tonnes of tiny shellfish growing on their backs. The shellfish are called barnacles. They need to have a solid surface to glue their shells on to. And rock, ship or passing whale will do.

What’s the difference between whales and dolphins?

Strictly speaking, dolphins are small whales with sharp, pointed teeth for catching food. Dolphins live in seas all over the world. The biggest dolphin is the killer whale.

Picture Credit : Google

What is the function of lungs?

The two lungs take up most of the space in the chest. Their key function is to get oxygen into, and waste gases out of, the bloodstream. That oxygen is used by the body’s cells to release energy, a process that produces waste carbon dioxide.

Breathing draws air rich in oxygen into the lungs through the airways, then pushes air containing carbon dioxide in the opposite direction. Lungs are spongy because they are packed with branching, air-filled tubes that get narrower and narrower before ending in tiny air sacs (alveoli). It is here that oxygen is swapped for carbon dioxide.

The lungs are like bellows. As they expand, air is sucked in for oxygen. As they compress, the exchanged carbon dioxide waste is pushed back out during exhalation.

When air enters the nose or mouth, it travels down the trachea, also called the windpipe. After this, it reaches a section called the carina. At the carina, the windpipe splits into two, creating two mainstem bronchi. One leads to the left lung and the other to the right lung.

From there, like branches on a tree, the pipe-like bronchi split again into smaller bronchi and then even smaller bronchioles. This ever-decreasing pipework eventually terminates in the alveoli, which are little air sac endings.

 

Picture Credit : Google

 

How blood clots?

After a cut, blood seeps from the wound, triggering an immediate repair process. The blood cells take action immediately. They stop the leak, form a plug, and destroy harmful bacteria. A scab forms, and the clot dissolves when the wound has healed.

Injury

A cut in the skin damages blood vessels. Platelets start to group together at the site of the injury.

Plug

The platelets release chemicals that make fibrin, a sticky thread-like protein. Red cells get stuck in the threads, forming a plug. White blood cells arrive to hunt for germs.

Clot

The fibrin threads contract, binding red blood cells and platelets together in a sticky clot, which closes the wound.

Scab

The clot near the skin’s surface dries out to form a protective scab, which covers the healing wound.

 

Picture Credit : Google