They have no brains and no spines. You can often see right through them. But they can cause painful, sometimes deadly stings. Some can even glow in the dark! Scientists know them as medusas, but most people call them jellyfish.
WHAT ARE JELLYFISH?
Jellyfish are not really fish. They are invertebrate animals. This means that unlike fish or people, they have no backbones. In fact, they have no bones at all.
Jellyfish have stomachs and mouths, but no heads. They have nervous systems for sensing the world around them, but no brains. They are made almost entirely of water, which is why you can look through them.
If you shouted “Hey, Joey!” at a zoo in Australia, people might think you were talking to a kangaroo. Joey is the name for a baby kangaroo. If you think that is interesting, there are some other things you should know about kangaroos.
Kangaroos are a special kind of mammal called a marsupial. Baby marsupials must live in a pouch on their mother’s abdomen. They have to live in the pouch because they are not fully developed when they are born. Ordinary mammals give birth to developed young with eyes, noses, inner organs, and limbs. Baby kangaroos have to finish their development in the pouch.
How far can you stick out your tongue? No matter how far you can stick it out, you cannot beat the chameleon. The chameleon can stick out its tongue up to twice the length of its body. The chameleon is a type of lizard. There are more than 4,300 different species (kinds) of lizard.
WHAT DO LIZARDS LOOK LIKE?
Lizards are reptiles. Snakes, alligators, and crocodiles are also reptiles. There are more species of lizard than of any other reptile. Like snakes, lizards have dry, scaly skin. Most lizards are only a few centimeters long. The biggest lizard is the Komodo dragon. It can be up to 10 feet (3 meters) long.
What if you could yell to a friend who lived several miles away—and your friend could hear you? That is how loud a lion can roar! No wonder this mighty animal is called the king of beasts.
Lions are big cats. Along with tigers, lions are the world’s biggest and strongest cats. There are two kinds of lions, African and Asian lions. Lions live on grassy plains, savannas, and dry woodlands in Africa and India. They do not like to live in jungles and thick forests.
Lions have huge shoulders, strong front legs, and powerful jaws. Their paws have long, sharp claws. To keep its claws sharp, a lion draws them in when not in use.
What is the same about a bat, a cat, a kangaroo, a shrew, and you? You and all these animals are mammals.
Most mammals are covered with hair or fur. Most mammals are animals that give birth to live young instead of laying eggs. All mammal mothers care for their babies and feed them mother’s milk. Mammal babies learn by watching their parents. Mammals are generally smarter than other kinds of animals.
There are about 4,600 species (kinds) of mammals. Most mammals live on land and move about on four legs. There are also mammals that walk or hop on two legs, mammals that live in water, and mammals that can fly.