Science notes, unit 4

Animals

Textbook Science Year 3 (DLP), pages 59–70

What this chapter covers

You can group animals by what they eat (4.1.1)
You can say what herbivores, carnivores and omnivores eat (4.1.2)
You can give examples of herbivores, carnivores and omnivores (4.1.3)
You can match the teeth of an animal to what it eats (4.1.4)
You can explain why some animals change what they eat (4.1.5)

4.1What do animals eat?

All animals need food to live and grow. But animals do not all eat the same food. Look at the pictures. What is each animal eating?

Rabbiteats leaves

Elephanteats leaves and grass

Eagleeats other animals

Snakeeats mice and frogs

Chickeneats seeds and worms

Monkeyeats fruit and insects

Pictures: Science Year 3 (DLP) textbook, p. 60.

An animal's eating habit means the kind of food it usually eats.

Scientists sort animals into groups. To classify means to put things into groups that are alike. We can classify animals by their eating habits. There are three groups:

animals that eat plants only
animals that eat other animals only
animals that eat plants and other animals

The rabbit and the elephant are in the same group. Why?

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Both of them eat plants only.

4.2Herbivores, carnivores and omnivores

Each group has a special science name. Learn these three words well.

Herbivore: an animal that eats plants only. Example: rabbit, cow, goat.
Carnivore: an animal that eats other animals only. Example: tiger, eagle, snake.
Omnivore: an animal that eats plants and other animals. Example: chicken, monkey, bear.

Easy way to remember: herbivore sounds like "herb", which is a plant. Carnivore sounds like "carne", which means meat. Omni means "all", so an omnivore eats all kinds of food.

Animals around us

Think about the animals you see every day.

The goats and cows in the kampung eat grass. They are herbivores.
The eagle flying over the padi field catches fish and mice. It is a carnivore.
The ayam kampung eats rice grains and worms. It is an omnivore.

Tree map: Animals split into herbivores (rabbit, cow, goat, elephant), carnivores (tiger, eagle, snake, shark) and omnivores (chicken, monkey, bear, orangutan) — A tree map sorts animals into groups

Example: classify the animal

A frog catches insects with its long tongue. It does not eat plants.
Food: other animals only, so the frog is a carnivore.

Some pupils think every animal that eats insects is a carnivore. Check if it also eats plants. A bat eats fruit and insects, so the textbook calls it an omnivore.

Is each animal a herbivore, carnivore or omnivore? (a) cat that eats fish and mice (b) grasshopper that eats leaves (c) duck that eats rice and snails

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(a) Carnivore (b) Herbivore (c) Omnivore

4.3Teeth of animals

Animals use their teeth to eat. The dentition of an animal means the kind of teeth it has. An animal's teeth match the food it eats.

Three teeth: a flat incisor, a pointed canine and a wide bumpy molar — Three types of teeth

Tooth	Shape	Job
Incisor	Flat and sharp at the edge, at the front of the mouth	Cuts food
Canine	Long and pointed	Tears meat
Molar	Big and wide, at the back of the mouth	Grinds (crushes) food into small pieces

Teeth of each group

Group	Skull	Mouth	Teeth
Carnivore (tiger)			Very sharp canines to tear meat
Herbivore			Strong incisors to cut plants and big molars to grind plants so they are easy to swallow
Omnivore			Incisors to cut, canines to tear and molars to grind

Skulls and photos: Science Year 3 (DLP) textbook, p. 64.

What if the teeth were wrong?

Imagine a goat with the pointed teeth of a lion. It could not cut grass well. A lion with flat front teeth could not tear meat. Teeth must suit the food.

Cartoon goat with pointed teeth struggling to cut grass — A goat with pointed teeth cannot cut grass easily.

Cartoon lion with flat front teeth struggling to tear meat — A goat with pointed teeth cannot cut grass easily.

Two cartoon orangutans: one tears a fish, the other cannot cut a banana — These orangutans have canines but no good incisors. They can tear fish but cannot cut a banana.

Cartoons: Science Year 3 (DLP) textbook, pp. 65–66.

Did you know? An elephant's long tusks are really two giant incisors! And a chicken has no teeth at all. It swallows its food and small stones help to crush it inside its body.

Ali's cat has long, pointed canines. Is the cat a herbivore, carnivore or omnivore? How do you know?

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Carnivore. Sharp canines are used to tear meat.

4.4Animals can change what they eat

Most bears are omnivores. They eat fruit, honey, fish and other animals.

Two photos of brown bears eating — Bears are naturally omnivores

Photos: Science Year 3 (DLP) textbook, p. 67.

The polar bear lives near the North Pole. It is always cold there and the ground is covered in ice. Plants cannot grow on ice. So the polar bear eats seals and fish only. The polar bear has changed its eating habit. It is a carnivore.

Animals may change their eating habits when their surroundings change, for example when their usual food is hard to find.

Example: the cat at home

A cat is naturally a carnivore. But a cat at home may eat rice mixed with fish, because that is the food people give it.

Did you know? The giant panda is a bear too, but it eats almost only bamboo!

Why does a polar bear eat other animals only?

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It lives in a cold place covered in ice. Plants cannot grow there, so it can only find other animals to eat.

Summary

Group	Eats	Teeth	Examples
Herbivore	Plants only	Strong incisors and big molars	Rabbit, cow, goat, elephant
Carnivore	Other animals only	Very sharp canines	Tiger, eagle, snake, frog
Omnivore	Plants and other animals	Incisors, canines and molars	Chicken, monkey, bear, bat

Incisors cut, canines tear, molars grind.
Animals may change their eating habits when their surroundings change (polar bear).