Animal Form, Function, and Behavior

Respiratory Adaptations are the special body parts animals use to breathe.

Breathing means taking in oxygen from air or water and getting rid of a waste gas called carbon dioxide.

Different animals live in different places. Because of that, they do not all breathe the same way.

Some animals breathe with lungs. Some use gills. Some can breathe through their skin. Some tiny animals use small holes called spiracles.

These special breathing body parts are called respiratory adaptations. An adaptation is something that helps a living thing survive.

Why do animals need respiratory adaptations?

Animals live in many places, like oceans, ponds, forests, deserts, and even underground.

An animal that lives in water needs a way to get oxygen from water. An animal that lives on land needs a way to get oxygen from the air.

Respiratory adaptations help animals breathe in the place where they live.

Lungs

Lungs are breathing organs inside the body.

Many land animals have lungs. People, dogs, cats, birds, and rabbits all use lungs.

Lungs take oxygen from the air when an animal breathes in. They also help the animal get rid of carbon dioxide when it breathes out.

Lungs work well on land because land animals are surrounded by air.

Example animals with lungs:

• People
• Dogs
• Birds
• Lizards
• Whales and dolphins come up to the surface to breathe air with lungs

Even though whales and dolphins live in water, they do not have gills. They must come to the top of the water to breathe air.

Gills

Gills are body parts that help animals get oxygen from water.

Fish use gills to breathe underwater.

As water moves over the gills, the gills take in oxygen from the water.

Gills are a great adaptation for animals that live in water.

Example animals with gills:

• Fish
• Many young frogs, called tadpoles
• Some other water animals

A fish cannot use its gills well on dry land. Gills work best in water.

Skin

Some animals can breathe through their skin.

The skin must stay wet or moist for this to work well.

Frogs and earthworms are good examples.

A frog can use its lungs, but it can also take in oxygen through its skin. This helps the frog live part of its life in water and part on land.

An earthworm does not have lungs like we do. It gets oxygen through its moist skin.

Example animals that can use skin to breathe:

• Earthworms
• Frogs

Spiracles

Spiracles are tiny holes on the sides of the bodies of many insects.

Air goes in and out through these small openings.

Insects like grasshoppers, ants, and beetles use spiracles to breathe.

Spiracles are different from lungs. They are also different from gills.

Example animals with spiracles:

• Ants
• Grasshoppers
• Beetles

How body parts match where animals live

An animal’s breathing body part matches its habitat, or the place where it lives.

• Fish live in water, so gills help them breathe.
• Dogs live on land, so lungs help them breathe air.
• Earthworms live in damp soil, so their moist skin helps them breathe.
• Insects use spiracles to take in air.

When we study respiratory adaptations, we ask: What body part helps this animal breathe where it lives?

Worked Examples

Example 1: Fish in a pond

A fish lives in a pond. Does it use lungs or gills?

Step 1: Think about where the fish lives. It lives in water.

Step 2: Animals that breathe in water often use gills.

Answer: The fish uses gills.

Example 2: Dog in a yard

A dog runs and plays in a yard. Does it use skin, gills, or lungs to breathe?

Step 1: Think about where the dog lives. It lives on land.

Step 2: Many land animals use lungs.

Answer: The dog uses lungs.

Example 3: Earthworm after rain

An earthworm is wriggling in wet soil after a rainstorm. What helps it breathe?

Step 1: Remember that earthworms do not have lungs like people.

Step 2: Earthworms take in oxygen through moist skin.

Answer: The earthworm uses its skin to breathe.

Example 4: Ant on a leaf

An ant crawls on a leaf. What special body part helps it breathe?

Step 1: An ant is an insect.

Step 2: Many insects breathe through tiny holes called spiracles.

Answer: The ant uses spiracles.

Let’s compare

• Lungs help many animals breathe air.
• Gills help many animals breathe in water.
• Skin can help some animals breathe if it stays moist.
• Spiracles are tiny openings insects use to breathe air.

Things to remember

1. Animals need oxygen to live.
2. Different animals have different breathing body parts.
3. These breathing body parts are called respiratory adaptations.
4. Respiratory adaptations help animals survive in their habitats.

Brief Summary

Animals do not all breathe the same way.

Some animals use lungs, some use gills, some use skin, and many insects use spiracles.

These respiratory adaptations help animals get oxygen from the place where they live, like air or water.

Digestive Specializations means that different animals have different body parts to help them eat and use their food.

Animals do not all eat the same things. Some animals eat mostly meat. Some eat mostly plants. Some eat both plants and meat.

The inside parts that help break down food are called the digestive tract. Teeth are also very important because they help start breaking food into smaller pieces.

Because animals eat different foods, their teeth and digestive tracts are special in different ways.

There are 3 main groups of eaters:

• Carnivores eat meat.
• Herbivores eat plants.
• Omnivores eat both plants and meat.

1. Carnivores

Carnivores are animals that eat other animals. Examples are lions, wolves, and hawks.

Carnivores often have sharp, pointed teeth. These teeth help them bite, tear, and cut meat.

Meat is easier to break down than many tough plant parts. Because of that, carnivores often have a shorter digestive tract than plant-eating animals.

Carnivore clues:

• Sharp teeth
• Teeth for tearing meat
• Usually a shorter digestive tract

2. Herbivores

Herbivores are animals that eat plants. Examples are cows, rabbits, and deer.

Plants can be hard to break down. Leaves, stems, and grass are tough. Herbivores often have flat, wide teeth to grind plants into tiny pieces.

Many herbivores also have a longer digestive tract. The longer path gives the body more time to break down plant food.

Herbivore clues:

• Flat teeth
• Teeth for chewing and grinding
• Usually a longer digestive tract

3. Omnivores

Omnivores eat both plants and meat. Examples are bears, raccoons, and humans.

Omnivores often have different kinds of teeth. They may have some sharper teeth for meat and some flatter teeth for plants.

Their digestive tracts work for both kinds of food. They are often in between the shorter tracts of many carnivores and the longer tracts of many herbivores.

Omnivore clues:

• More than one kind of tooth
• Can chew plants and meat
• Digestive tract fits a mixed diet

Why do teeth matter?

Teeth are the first helpers in digestion. They break food into smaller pieces so the body can use it more easily.

Sharp teeth are good for tearing. Flat teeth are good for grinding.

If an animal eats meat, tearing teeth help. If an animal eats plants, grinding teeth help. If an animal eats both, having both kinds helps.

Why does the digestive tract matter?

After food is chewed, it travels through the digestive tract. The body keeps breaking the food down and takes in what it needs.

Plant foods are often tougher to break down, so many plant-eating animals need a longer digestive tract. Meat is often broken down faster, so many meat-eating animals have a shorter digestive tract.

Let’s compare the 3 groups.

• Carnivore: eats meat, has sharp teeth, often has a shorter digestive tract
• Herbivore: eats plants, has flat teeth, often has a longer digestive tract
• Omnivore: eats both, has a mix of teeth, has a digestive tract that works for both foods

Worked Example 1

A lion has sharp teeth. It uses them to tear meat. Is a lion a carnivore, herbivore, or omnivore?

Step 1: Think about what the lion eats. It eats meat.

Step 2: Match that food to the animal group.

Answer: A lion is a carnivore.

Worked Example 2

A cow has flat teeth that grind grass. Grass is a plant. Is a cow a carnivore, herbivore, or omnivore?

Step 1: Think about the food. Grass is a plant.

Step 2: Animals that eat plants are herbivores.

Answer: A cow is a herbivore.

Worked Example 3

A bear eats fish, berries, and plants. It has different kinds of teeth. Is a bear a carnivore, herbivore, or omnivore?

Step 1: Fish is meat. Berries and plants are plant foods.

Step 2: Animals that eat both plants and meat are omnivores.

Answer: A bear is an omnivore.

Worked Example 4

Which animal would most likely need more grinding teeth: a rabbit that eats plants or a fox that eats meat?

Step 1: Plants usually need grinding.

Step 2: Herbivores often have flat teeth for grinding.

Answer: The rabbit would most likely need more grinding teeth.

Easy way to remember:

• Meat eater = sharp teeth
• Plant eater = flat teeth
• Both = a mix of teeth

Another easy way to remember:

• Plants are tougher to break down, so herbivores often have longer digestive tracts.
• Meat is often easier to break down, so carnivores often have shorter digestive tracts.

Let’s check our thinking.

1. If an animal has sharp teeth for tearing meat, it may be a carnivore.
2. If an animal has flat teeth for grinding leaves, it may be a herbivore.
3. If an animal eats both meat and plants, it is an omnivore.

Summary

Animals have special body parts that match the foods they eat. Carnivores eat meat and often have sharp teeth and shorter digestive tracts. Herbivores eat plants and often have flat teeth and longer digestive tracts. Omnivores eat both plants and meat, so they often have a mix of teeth and digestive systems that can handle both kinds of food.

Metamorphosis and Life Cycles

Animals grow and change as they live. The way an animal changes from the beginning of its life to an adult is called its life cycle.

Some animals look a lot like their parents when they are born or hatch. Other animals change a lot as they grow. A big change in body form is called metamorphosis.

In this lesson, we will learn about three kinds of life cycles:

• Complete metamorphosis
• Incomplete metamorphosis
• Direct development

We will also learn how to tell them apart.

1. What is a life cycle?

A life cycle is the order of stages an animal goes through as it grows. It starts at the beginning of life, then the animal grows, and finally becomes an adult.

Many adult animals lay eggs or have babies. Then the life cycle begins again.

2. What is metamorphosis?

Metamorphosis means an animal changes a lot as it grows. Its body can look very different at each stage.

For example, a caterpillar does not look like a butterfly. A tadpole does not look like a frog. These animals go through metamorphosis.

3. Complete metamorphosis

Some insects go through complete metamorphosis. This means they have 4 stages.

1. Egg
2. Larva
3. Pupa
4. Adult

We can show the number of stages like this: \(2 + 2 = 4\) stages.

In complete metamorphosis, the young animal looks very different from the adult.

Butterfly example:

• Egg: A butterfly starts as an egg.
• Larva: The egg hatches into a caterpillar. The caterpillar eats a lot and grows.
• Pupa: The caterpillar forms a chrysalis. Inside, its body changes.
• Adult: A butterfly comes out.

Other animals that can have complete metamorphosis include beetles, flies, and bees.

4. Incomplete metamorphosis

Some insects go through incomplete metamorphosis. This means they have 3 stages.

1. Egg
2. Nymph
3. Adult

We can show the number of stages like this: \(1 + 2 = 3\) stages.

In incomplete metamorphosis, the young animal looks like a small version of the adult, but it is not fully grown yet.

A nymph does not have all the adult body parts yet. It may not have wings, or its wings may be very small.

Grasshopper example:

• Egg: A grasshopper starts as an egg.
• Nymph: The egg hatches into a nymph. It looks like a small grasshopper.
• Adult: The nymph grows bigger and becomes an adult grasshopper.

Other animals that can have incomplete metamorphosis include crickets and dragonflies.

5. Direct development

Some animals do not go through metamorphosis. They have direct development.

In direct development, the baby looks like a small form of the parent. As it grows, it gets bigger and stronger, but it does not change into a totally different body form.

Examples of direct development:

• Dogs
• Cats
• Birds
• Humans
• Lizards

A puppy looks like a small dog. A baby bird looks like a small bird. A human baby grows into an adult human. These are examples of direct development.

6. Frog life cycle

Frogs also change a lot as they grow. A frog starts as an egg, hatches into a tadpole, and later becomes an adult frog.

The tadpole has a tail and lives in water. As it grows, it gets legs and loses its tail. Then it becomes an adult frog.

This is a life cycle with big changes, so it is a kind of metamorphosis.

7. How are these life cycles different?

• Complete metamorphosis: 4 stages and a very big change in body form.
• Incomplete metamorphosis: 3 stages and the young looks somewhat like the adult.
• Direct development: no metamorphosis; the young looks like a smaller version of the parent.

8. Why do life cycles matter?

Life cycles help us understand how animals grow, survive, and have young.

Each stage can help an animal live in its habitat. For example, a caterpillar is good at eating leaves, and a butterfly is good at flying to flowers.

Worked Example 1: Butterfly stages

Question: A butterfly has these stages: egg, larva, pupa, adult. Is this complete metamorphosis, incomplete metamorphosis, or direct development?

Step 1: Count the stages. There are 4 stages.

Step 2: Check if there is a larva and a pupa. Yes.

Answer: This is complete metamorphosis.

Worked Example 2: Grasshopper stages

Question: A grasshopper has these stages: egg, nymph, adult. What kind of life cycle is this?

Step 1: Count the stages. There are 3 stages.

Step 2: Look for the word nymph. A nymph means the young looks like a small adult.

Answer: This is incomplete metamorphosis.

Worked Example 3: Puppy growth

Question: A puppy grows into a dog. The puppy looks like a small dog. Is this metamorphosis?

Step 1: Ask: Does the young look very different from the adult? No.

Step 2: Ask: Does it have larva, pupa, or nymph stages? No.

Answer: This is direct development, not metamorphosis.

Worked Example 4: Compare two animals

Question: Which animal changes more as it grows: a butterfly or a chicken?

Step 1: A butterfly starts as an egg, becomes a caterpillar, then a pupa, then an adult butterfly.

Step 2: A chicken hatches from an egg and looks like a small chicken as it grows.

Step 3: Decide which one has the bigger body change.

Answer: The butterfly changes more because it goes through complete metamorphosis.

9. Clues to help you identify the life cycle

• If you see egg, larva, pupa, adult, it is complete metamorphosis.
• If you see egg, nymph, adult, it is incomplete metamorphosis.
• If the baby looks like a small parent, it is usually direct development.
• If the animal changes into a very different body form, it is metamorphosis.

10. Let’s compare them side by side

• Complete metamorphosis: butterfly, beetle, bee
• Incomplete metamorphosis: grasshopper, cricket, dragonfly
• Direct development: dog, bird, human, lizard

Summary

A life cycle is how an animal grows from the beginning of life to an adult. Metamorphosis is a big change in body form as an animal grows.

Complete metamorphosis has 4 stages: egg, larva, pupa, adult. Incomplete metamorphosis has 3 stages: egg, nymph, adult. Direct development means the young looks like a smaller version of the parent.

When you study an animal’s stages, you can tell how it grows and what kind of life cycle it has.

Mammalian Structural Adaptations

Today we will learn about mammals. Mammals are a group of animals with special body parts that help them live and grow.

A body part that helps an animal survive is called an adaptation. An adaptation is something about an animal's body that helps it stay safe, warm, fed, and alive.

Mammals have some important body traits that help us identify them. We can look for hair or fur, mothers that make milk for their babies, and lungs that help them breathe air.

1. Mammals have hair or fur

Hair and fur cover the bodies of mammals. This covering helps keep their bodies warm. It is like wearing a cozy blanket or jacket.

Some mammals have lots of thick fur, like bears and cats. Some mammals have only a little hair, like people or elephants. Even if a mammal does not look very furry, it still has some hair.

Hair or fur can help in other ways too.

• It helps protect skin.
• It helps animals stay warm when it is cold.
• It can help animals blend in.

2. Mammal mothers make milk for their babies

One very special mammal trait is that mother mammals make milk. The milk feeds the babies when they are small.

This helps baby mammals grow strong. Kittens drink milk from their mother. Puppies do too. Human babies also drink milk when they are very young.

This is a big clue that an animal is a mammal.

3. Mammals breathe with lungs

Mammals use lungs to breathe air. Lungs are body parts inside the chest. They take in air and help the body get what it needs to live.

People use lungs. Dogs use lungs. Whales and dolphins are mammals too, and they use lungs. Even though whales live in water, they must come up to the surface to breathe air.

Why these body parts help mammals survive

Mammals need to stay warm, feed their young, and breathe air. Their body parts help them do these jobs.

• Hair or fur helps keep them warm.
• Milk helps babies grow.
• Lungs help them breathe.

These adaptations help mammals live in many places. Mammals can live in forests, deserts, farms, homes, and even the ocean.

Examples of mammals

• Dog
• Cat
• Cow
• Horse
• Bear
• Bat
• Whale
• Human

All of these animals are mammals because they have hair or fur, mother mammals make milk for babies, and they breathe with lungs.

Animals that are not mammals

Some animals are not mammals. Birds have feathers. Fish have gills. Reptiles have dry scales. These animals are not mammals because they do not have the same special mammal traits.

For example, a fish does not have fur. A bird does not make milk for its babies. A snake does not have hair.

Worked Example 1

Question: A kitten has fur. Its mother makes milk for it. Is the kitten a mammal?

Think: We look for mammal traits. Does it have fur? Yes. Does its mother make milk? Yes.

Answer: Yes. The kitten is a mammal.

Worked Example 2

Question: A fish lives in water. It has no fur and uses gills, not lungs. Is it a mammal?

Think: Mammals have hair or fur and breathe with lungs. This animal has no fur and no lungs.

Answer: No. A fish is not a mammal.

Worked Example 3

Question: A whale lives in the ocean. It breathes air with lungs and is fed milk by its mother when it is a baby. Is it a mammal?

Think: Mammals breathe with lungs and mother mammals make milk. A whale has these traits.

Answer: Yes. A whale is a mammal.

Worked Example 4

Question: A bird has feathers and lays eggs. It does not have fur. Is it a mammal?

Think: Mammals have hair or fur. Birds have feathers instead.

Answer: No. A bird is not a mammal.

Let’s remember the big clues

1. Look for hair or fur.
2. Remember that mother mammals make milk for babies.
3. Check if the animal breathes air with lungs.

If an animal has these mammal traits, it is a mammal.

Brief Summary

Mammals are animals with special body adaptations. They have hair or fur, mother mammals make milk for their babies, and they breathe with lungs. These body parts help mammals stay warm, grow, and live in many places.

Innate and Learned Behaviors

Animals do many different things to stay alive. They find food, stay safe, care for babies, and find homes. These actions are called behaviors.

Some behaviors are things animals are born knowing how to do. Other behaviors are things animals learn by watching, trying, and practicing.

In this lesson, we will learn about two kinds of behavior: innate behaviors and learned behaviors.

What Is an Innate Behavior?

An innate behavior is a behavior an animal is born with. The animal does not need to be taught. It happens naturally.

You can think of innate behavior as a built-in action. Right from the start, the animal knows how to do it.

• A spider spins a web.
• A baby sea turtle moves toward the ocean after hatching.
• A bird builds a nest.
• A duckling can swim soon after it hatches.

These behaviors help animals survive. They help animals get food, stay safe, and care for their young.

What Is a Learned Behavior?

A learned behavior is a behavior an animal is not born knowing. The animal learns it from experience, practice, or by watching others.

Learned behaviors can get better over time. The more an animal practices, the better it may do.

• A puppy learns to sit when a person trains it.
• A young bird learns songs by hearing older birds.
• A bear learns where to find fish in a river.
• A monkey learns how to use a stick to get food.

How Are They Different?

The big difference is when and how the behavior starts.

• Innate behavior: born with it
• Learned behavior: taught or practiced

If an animal can do something without anyone showing it how, that behavior is probably innate.

If an animal has to watch, practice, or be trained, that behavior is probably learned.

Why Do Animals Need Both?

Animals need behaviors to survive in their habitats. Some behaviors must happen right away. For example, a baby animal may need to move, drink milk, or hide very quickly. Innate behaviors help with that.

Animals also live in changing places. They may need to learn where food is, which places are safe, or how to live near other animals. Learned behaviors help with that.

So, both kinds of behavior are important.

Examples of Innate Behaviors

• A kangaroo baby crawls into its mother's pouch.
• A porcupine raises its sharp quills when in danger.
• A beaver builds a dam.
• A deer runs when it hears a sudden scary sound.

These actions are not taught in the same way as a classroom lesson. They are natural actions that help the animal survive.

Examples of Learned Behaviors

• A cat learns that a can opener sound means food is coming.
• An elephant learns a path to water.
• A dolphin learns to follow signals from a trainer.
• A young lion learns hunting skills by watching adult lions.

These actions come from experience. The animal learns something new over time.

Worked Example 1

Question: A spider spins a web. Is this innate or learned?

Step 1: Ask, “Was the spider born knowing how to do this, or did someone teach it?”

Step 2: Spiders are born with this behavior.

Answer: This is an innate behavior.

Worked Example 2

Question: A dog learns to shake hands after many days of practice. Is this innate or learned?

Step 1: Ask, “Did the dog need practice or training?”

Step 2: Yes, the dog practiced and learned it.

Answer: This is a learned behavior.

Worked Example 3

Question: A baby turtle hatches from an egg and moves toward the sea. Is this innate or learned?

Step 1: Ask, “Did the baby turtle need to be taught?”

Step 2: No, it does this naturally.

Answer: This is an innate behavior.

Worked Example 4

Question: A young bird listens to older birds and learns a song. Is this innate or learned?

Step 1: Ask, “Did the bird learn by hearing others?”

Step 2: Yes, it learned by listening.

Answer: This is a learned behavior.

How to Figure It Out

When you are trying to decide if a behavior is innate or learned, ask these questions:

1. Was the animal born knowing how to do it?
2. Did the animal need to watch, practice, or be taught?
3. Does the behavior help the animal survive?

If the answer to the first question is yes, it is probably innate.

If the answer to the second question is yes, it is probably learned.

Let’s Compare

• Bird building a nest: innate
• Dog learning a trick: learned
• Deer running from danger: innate
• Young lion learning to hunt: learned

Important Idea

Some animals use both innate and learned behaviors. For example, a young lion may be born with the instinct to chase, but it still learns better hunting skills by watching adult lions.

That means animal behavior can be a mix of what an animal is born with and what it learns later.

Summary

Behaviors are the things animals do.

Innate behaviors are actions animals are born knowing how to do. Learned behaviors are actions animals gain from practice, experience, or watching others.

Both kinds of behavior help animals live, grow, and survive in their world.

Animal Social Structures

Animals live in different ways. Some animals live alone. Other animals live in groups.

How an animal lives with others is called its social structure. A social structure is the way animals are organized when they live alone or together.

Animals do not all choose the same way to live. Different ways of living help different animals find food, stay safe, care for babies, and survive.

1. Animals That Live Alone

Some animals are solitary. Solitary means they spend most of their time alone.

A solitary animal may hunt alone, sleep alone, and protect its own space. It may only come near other animals when it is time to mate or raise babies.

Living alone can help an animal in some ways:

• It does not have to share as much food.
• It can hide more easily.
• It can move quietly when hunting.

Living alone can also be hard:

• It has no group to help protect it.
• It must find food by itself.
• It must watch for danger by itself.

Examples of animals that often live alone are:

• tigers
• bears
• leopards

2. Animals That Live in Groups

Some animals live together in groups. Group living can help animals work together.

Animals in groups may:

• look for food together
• protect one another
• care for babies
• warn each other about danger

But group living can also have problems:

• Animals may need to share food.
• Groups can be easier for predators to see.
• Animals in a group may argue or compete.

3. Herds

A herd is a group of animals that stays together. Many plant-eating animals live in herds.

Zebras, deer, and elephants can live in herds. When many animals stay together, they can help keep each other safe.

If one animal sees danger, it may run or make a sound. Then the others know to move too. Many eyes and ears can help a herd notice danger faster.

Herds also help babies. Baby animals can stay close to many adults.

4. Packs

A pack is a group of animals that works together closely. Wolves are a common example of animals that live in packs.

Animals in a pack may hunt together. Working together can help them catch food that may be hard to catch alone.

Packs may also protect their group and their young. Each animal in the pack can help in some way.

5. Colonies

Some animals live in very organized groups called colonies. Ants, bees, and termites are examples.

In these groups, different animals do different jobs. Some gather food. Some protect the colony. Some care for eggs and babies.

These very organized colonies are called eusocial colonies. That means the animals work together in special ways and share jobs.

For example, in a bee colony:

• some bees collect nectar
• some bees guard the hive
• some bees care for young bees

Because they work together, the whole colony can survive better.

6. Why Social Structures Matter

An animal's social structure helps it meet its needs. Needs include food, water, shelter, safety, and care for young.

No social structure is perfect for every animal. Living alone has benefits and costs. Living in groups also has benefits and costs.

Scientists study animal behavior to learn why one animal lives alone while another lives in a herd, pack, or colony.

Worked Example 1

Question: A tiger hunts by itself and spends most of its time alone. Is it solitary or does it live in a group?

Step 1: Think about what solitary means. Solitary animals spend most of their time alone.

Step 2: The tiger hunts by itself and lives alone most of the time.

Answer: The tiger is solitary.

Worked Example 2

Question: A group of zebras stays together. If one zebra sees a lion, the others run too. What is one benefit of living in a herd?

Step 1: Herds stay together in groups.

Step 2: One zebra notices danger.

Step 3: The other zebras learn about the danger quickly.

Answer: One benefit of living in a herd is staying safer from danger.

Worked Example 3

Question: Wolves work together to catch food. Is this more like a herd, a pack, or solitary living?

Step 1: Packs are groups that work closely together.

Step 2: The wolves are working together to catch food.

Answer: This is a pack.

Worked Example 4

Question: In an ant colony, some ants find food and some ants protect the nest. What does this tell us about ant social structure?

Step 1: Colonies can have different jobs for different animals.

Step 2: The ants are sharing jobs.

Answer: Ants live in a colony where animals work together and do different jobs.

Let’s Remember

• Solitary animals live mostly alone.
• Herds are groups that stay together for safety.
• Packs work closely together, often to hunt or protect one another.
• Colonies are organized groups where animals may have different jobs.
• Both living alone and living in groups have benefits and costs.

Brief Summary

Animals have different social structures. Some live alone, and some live in groups like herds, packs, and colonies.

Living alone can mean less sharing, but less help. Living in a group can mean more protection and teamwork, but also more sharing and competition.

These social structures help animals survive in different ways.