NCERT Solutions for Class 4 EVS Chapter 2

In some animals we can see the ears, in some we cannot. No, they have ears in tiny shape which are not visible. We cannot see a bird’s ears. A bird has tiny holes on both sides of its head. Generally, the holes are covered with feathers. They help the bird to hear.

We Have seen animals around our house or school that have small babies for example cow, pig, dog and several types of bird.

Yes, we have several pets when I was lived in my village like cow, buffalo etc. now in cities trend has been changed I know several people who keep pet like dog and cat.

This is a little puppy.

Yes, his name is “tomy”.

He like to eat milk and rusk.

In a day it is given food three time.

He is a lazy puppy, it sleeps mostly.

Pet animals require lot of care specially dogs. First of all, keep in mind their hygiene for good health and feed them carefully and on right time. We should fix the time for outing.

He gets angry when some tease him or when someone unknown person enters in house. When he becomes angry barking loudly and jumping here and there.

It has hair on its skin

Yes, we can see its ears.

It is a baby animal.

This pet animal give birth to babies.

No, it is itself a small puppy.

An elephant uses its ears in the following ways-
• To hear long distance sounds
• To keep its body cool
• To communicate joys and sorrows, show anger, excitement by flapping the ears

Elephants keep moving or flapping their ears in hot weather to keep their body cool. Flapping the ears helps to cool an elephant as the ears act as a fan and move air over the rest of the elephant’s body, flapping also cools the blood as it circulates through the veins in the ears.

Bats have large ears on their small head which help them to navigate or find their way in the dark as their vision is not good in comparison to the other animals.

Every night a bat puts in 600-700 kilometres of airtime. Flying at a low level, the bat catch insects at speeds of around 40 metres per second. At night, the bat uses its ears which are good at hearing to find its prey. Bats catch insects continuously using sound which as a navigation system.

Hair on the body is a body covering that –
• Keeps the animal warm and dry
• Gives different pattern to the animal on their skin
• Protects them from any danger like enemies
• Protects them from harsh weather conditions
• Helps them to hide from their enemies (Camouflage)

The features of the mammals are as given below-
• They give birth to their young ones directly
• Most of them live on land
• They have four limbs
• They have hair on their body
• The young ones feed on their mother’s milk
• They have ears which can be seen

Mammals are the organisms which have mammary glands to produce milk, they give birth to young ones and have hair on their body. They are also warm blooded e.g., human beings, cat, dogs, monkeys, cow etc.

Reproduction is the process by which the living things produce young ones of their own kind. Some living things reproduce by laying eggs and some give birth to the young ones directly.

Reproduction is an important process which helps animals to-
• Increase the number of animals
• Prevent extinction of animals
• Maintain continuity of life.

The animals reproduce by two ways-
• By laying eggs- birds, reptiles, fish and amphibians
• By giving birth to the young ones directly-mammals

Hearing is birds’ important sense, and their ears are funnel-shaped which help them to hear sound. The ears are located slightly behind and below the eyes, and they are covered with soft feathers. Although the birds do not have external ears, their ears help them to identify sounds coming from different levels. Birds are also able to make out whether the source of a sound is above them, below them, or at the same level.

There are different patterns on the animal body due to the hair on their skin. If the animal did not have any hair on its skin then there would be no patterns. These patterns or stripes present on the body of animals match with their surroundings like grass, plants etc and are very useful for them. The patterns prevent animals from being spotted by the enemies. For e.g. when zebra hides itself behind the grass, these stripes confuse the enemies in identifying it and thus protects it

India has a habitat to support about 10,000 tigers in the country, but the number of tiger is decreasing day by day due to the cutting of forests resulting in loss of habitat and less availability of preys to feed on. Thus human activities, such as hunting, poaching and habitat destruction, are the reasons why some species of tigers have declined over the years.

Snakes do not have external ears but they can hear the vibrations with the help of their internal ear which are present in their jaw bones. Snakes feel the waves of the sound and transfer it to the internal ear to take action. Snake moves its body in response to the sound waves obtained from it.

A bird’s ears are not visible to us because it does not have external ear structures. Its ears are like openings that are hidden under the feathers on the side of the head, just behind and slightly below the eyes. Birds do have ears and an excellent sense of hearing and are able to hear a much wider range of sounds than humans, but we can’t see their ears because they are covered with feathers. The feathers that cover the ear hole protect it from the noise of the wind as the bird flies.

Animals can be recognised by skin due to the smell generated by the sweat glands present in the skin of animals.

Crocodiles are the only reptiles with external ear. Their ears are located behind their eyes, in the upper part of their heads. They have flaps which cover their ears forming a tight seal, preventing water from entering the ear when they are in water.

Bats have large ears. Bats have a bad eyesight, being blind for the most part so they depend upon their sense of hearing. A bat can shrill at the same time as in flight and navigate their way to where they need to be.

Platypuses are grouped as separate type of mammals which are different from all other mammals because they do not give birth to the young ones directly but they lay eggs.

The platypus is considered a mammal because it has fur on its body and feeds its young with milk.

Pangolins are actually mammals. They are the only mammals whose whole body is covered in scales and they use those scales to protect themselves from enemies in the wild.

Pangolins are covered in hard scales. These mammals eat ants and termites using an very long, sticky tongue, and are able to quickly roll themselves up into a tight ball when they feel threatened.

Nocturnal animals are those animals that are active at night time and then sleep during the day. There are many examples of nocturnal animals, including hedgehogs, foxes, owls, bats. Since they are awake when it is dark outside, their bodies adapt them to survive.

These animals are active during the night hours. Animals that are diurnal are usually awake and active during the day. These animals are well adapted to live during daylight. Many diurnal animals are inactive during night time because their body temperature drops at night. Examples include human, many birds, deer, cows etc.

(i). Hair -The most important function of hair in mammals is that it prevents the body against cold by conserving body heat. The different colours and colour patterns in hair coats also serve purpose of camouflage.
(ii). Ear- The ear is the organ that enables the mammals to hear and maintain balance of the body.

Many animals move their ears to focus their attention on sound. Many animals, including dogs, cats and various species of monkeys move their ears for better focus.

The features which help fish to adapt to live in water:
• It has streamlined body which is covered with scales.
• The skeleton is made up of thin bones with a flexible backbone.
• It is a cold blooded animal with flat fins
• fins and tails help them swim and also help to change direction and keep the body balanced.
• Gills that are the organs used for respiration in fishes. They are capable of absorbing oxygen from the water.

Reptiles are a group of cold-blooded animals which have skins covered with small hard plates called scales.They breathe through lungs and reproduce by laying eggs. Their skin is dry, and rough, without any glands. The body is divided into head, neck, trunk, and tail. Example-Snakes, lizards, and crocodiles are reptiles.

Amphibians are a class of animals like reptiles, mammals, and birds. They live in the water and on the land. When they hatch from their eggs, amphibians have gills so they can breathe in the water. They also have fins to help them swim, just like fish.

A vertebrate is an animal that has a backbone and a skeleton. It includes humans. It refers to those animals who have a backbone that protects their spinal cord.

Hibernation is also known as winter sleep. The warm and cold blooded animals undergo hibernation. It is a inactive stage in which all the activities of animals slow down. They maintain constant body temperature.