Grade III – EVS/Science
1. Nutrition
Nutrition is the process by which living things take in food and use it for energy, growth, repair, and staying healthy.
Animals cannot make their own food like green plants do. Therefore, they depend on plants or other animals for food.
Animals need food to:
- get energy to work and move,
- grow properly,
- repair damaged body parts,
- stay healthy and strong.
2. What Do Animals Eat?
Different animals eat different kinds of food. Their food depends on their body structure, teeth, beak, tongue, and digestive system.
Animals may eat:
- Grass and leaves – cow, goat, deer
- Fruits and vegetables – monkey, elephant
- Seeds and grains – sparrow, pigeon
- Meat of other animals – lion, tiger
- Insects – frog, lizard
- Both plants and animals – bear, crow, human beings
Based on what they eat, animals can mainly be divided into herbivores, carnivores, and omnivores.
3. Herbivores
Herbivores are animals that eat plants and plant products.
They may eat grass, leaves, fruits, vegetables, seeds, or grains.
Examples:
- Cow
- Goat
- Deer
- Rabbit
- Horse
- Elephant
- Giraffe
Special features
Herbivores usually have flat and broad teeth that help them cut and grind plant food.
Example: A cow uses its teeth to chew grass.
4. Carnivores
Carnivores are animals that eat the flesh or meat of other animals.
Examples:
- Lion
- Tiger
- Leopard
- Wolf
- Eagle
- Snake
Carnivores generally have sharp teeth and claws that help them catch and tear their food.
Example: A lion uses its sharp teeth to tear meat.
5. Omnivores
Omnivores are animals that eat both plants and animals.
Examples:
- Human beings
- Bear
- Crow
- Hen
- Pig
- Some species of monkey
For example, a bear may eat fruits, roots, insects, fish, and other foods.
Omnivores have teeth that help them eat different kinds of food.
6. Cud
Cud is partly digested food that some animals bring back from their stomach to their mouth and chew again.
Animals such as cows, goats, sheep, and buffaloes eat grass and other plant food quickly. Later, they bring the food back into their mouth and chew it properly.
7. Chewing the Cud
The process of bringing partly digested food back to the mouth and chewing it again is called chewing the cud.
Animals such as cows, goats, sheep, and buffaloes chew the cud.
Why do they chew cud?
It helps them:
- break down food into smaller pieces,
- mix the food with saliva,
- digest tough plant food more easily.
Example: A cow first swallows grass and later brings it back to its mouth and chews it again.
8. Gnawing
Gnawing means biting and chewing something repeatedly with the front teeth.
Animals such as rats, rabbits, squirrels, and mice gnaw their food.
Their front teeth are strong and suitable for gnawing.
Example: A rabbit gnaws on a carrot.
9. Lapping
Lapping means taking liquid food or water into the mouth with the tongue.
Animals such as dogs and cats lap water or milk with their tongues.
Example: A dog laps up water from a bowl.
10. Food Chain
A food chain shows how food and energy pass from one living thing to another.
Usually, a food chain begins with a green plant, because plants make their own food.
Example:
Grass → Grasshopper → Frog → Snake → Eagle
Here:
- Grass is the producer.
- Grasshopper eats the grass.
- Frog eats the grasshopper.
- Snake eats the frog.
- Eagle eats the snake.
Another simple food chain:
Grass → Deer → Tiger
The arrows show the direction in which food and energy pass.
11. Quick Comparison
Type of Animal
What does it eat?
Examples
Herbivore
Plants
Cow, goat, deer, rabbit
Carnivore
Other animals/meat
Lion, tiger, eagle, snake
Omnivore
Plants and animals
Bear, crow, hen, human
12. Important Points to Remember
- Animals need food for energy, growth, and good health.
- Animals cannot make their own food.
- Herbivores eat plants.
- Carnivores eat other animals.
- Omnivores eat both plants and animals.
- Cud is partly digested food brought back to the mouth for chewing.
- Cows, goats, sheep, and buffaloes chew the cud.
- Gnawing means biting and chewing repeatedly with the front teeth.
- Rabbits, rats, mice, and squirrels gnaw.
- Lapping means taking liquid with the tongue.
- Dogs and cats commonly lap water.
- A food chain shows how food and energy pass from one organism to another.
- Most food chains begin with a green plant.