Taught through the hoglets, from fifteen minutes old
Approx. 45 minutes · KS2 · Also usable as two shorter sessions
Before you start
We have filmed our own baby hedgehogs — called hoglets — from fifteen minutes old until they were grown up. You can watch them do everything in this lesson.
Take as long as you like. Nothing here is timed.
What you'll learn to do
- Say what a life cycle is.
- Describe the life cycle of a mammal, a bird, an amphibian and an insect.
- Spot what is the same in all of them, and what is different.
- Explain what metamorphosis means.
Part 1 — What is a life cycle?
A life cycle is all the stages a living thing goes through, from the very start of its life to becoming an adult that can have young of its own.
It is called a cycle because it goes round. The young grow up, have their own young, and it starts again.
Every animal has one. They are not all the same shape.
Part 2 — A mammal: the hedgehog
Hoglets are born tiny, pink and blind. Their spines are soft and hidden under the skin so they do not hurt their mother.
| Stage | What happens |
|---|---|
| Born | Tiny, pink, blind, deaf. Soft white spines appear within hours. |
| Baby | Drinks only milk from its mother. Cannot keep itself warm. |
| Eyes open | At about two weeks. Starts to explore. |
| Weaning | Around six weeks. Starts eating solid food instead of milk. |
| Adult | Fully grown. Can have hoglets of its own. |
The mammal pattern: born alive, fed on milk, looks like a small version of the adult, gets bigger.
Notice this
A hoglet looks like a hedgehog from the day it is born. It is just very small and not very good at being one yet. Remember that — it will matter in Part 5.
Check yourself
Why are a newborn hoglet's spines soft?
Answer
So they do not hurt the mother while the hoglet is being born, and so the hoglets do not hurt each other in the nest. They harden as the hoglet grows.Part 3 — A bird: the galah
Rosie is a galah, a kind of cockatoo. Birds do it differently.
| Stage | What happens |
|---|---|
| Egg | Laid with a hard shell. The chick grows inside it. |
| Hatching | The chick breaks out of the shell. |
| Chick | No feathers or very few. Cannot fly. Fed by its parents. |
| Fledgling | Feathers grown. Learning to fly. |
| Adult | Fully feathered. Can have chicks of its own. |
The bird pattern: starts in an egg outside the mother's body, hatches, grows feathers, learns to fly.
Check yourself
Name one thing that is the same about a hedgehog's life cycle and a galah's, and one thing that is different.
Answer
Same: both are looked after and fed by a parent when they are young. Both grow bigger until they are adults.
Different: the hedgehog is born alive from its mother. The galah starts inside an egg that is laid.
Part 4 — An amphibian: the frog
This one changes shape completely.
| Stage | What happens |
|---|---|
| Egg | Soft jelly eggs, called spawn, laid in water. |
| Tadpole | Hatches. Has a tail. Breathes through gills. Lives in water. |
| Growing legs | Back legs first, then front legs. The tail starts to shrink. |
| Froglet | Almost a frog, still has a little tail. Starting to breathe air. |
| Adult frog | No tail. Breathes with lungs. Can live out of water. |
Look at what changed. A tadpole has gills and a tail and lives in water. An adult frog has lungs and no tail and can live on land.
That is a huge change. It has a name.
Part 5 — Metamorphosis
Metamorphosis means a big change of body shape during a life cycle.
Compare the two:
No metamorphosis — the hedgehog. A hoglet looks like a small hedgehog. It grows bigger. Its body shape does not change into something else.
Metamorphosis — the frog. A tadpole does not look like a small frog. It looks like nothing of the sort. Its body rebuilds itself.
Insects do this too
Our stick insects and mantises have life cycles like this:
Egg → nymph → adult. A nymph looks a bit like a small adult without wings. It sheds its skin again and again as it grows. This is called incomplete metamorphosis.
A butterfly is different again:
Egg → caterpillar → chrysalis → butterfly. A caterpillar looks nothing like a butterfly. This is complete metamorphosis.
Check yourself
A tadpole and a hoglet are both babies. Explain why only one of them goes through metamorphosis.
Answer
The hoglet already has the same body shape as an adult hedgehog. It only needs to grow bigger, so there is no metamorphosis.
The tadpole has a completely different body from an adult frog — it has gills instead of lungs and a tail instead of legs. Its body has to change shape to become a frog, and that change of shape is metamorphosis.
Part 6 — Questions
1. What does "life cycle" mean? (1 mark)
Answer
All the stages a living thing goes through from the start of its life until it is an adult that can have young of its own.2. Put these frog stages in order: froglet, egg, adult frog, tadpole. (1 mark)
Answer
Egg → tadpole → froglet → adult frog.3. Give two differences between a tadpole and an adult frog. (2 marks)
Answer
Any two of: the tadpole has gills, the frog has lungs; the tadpole has a tail, the frog does not; the tadpole has no legs, the frog does; the tadpole lives only in water, the frog can live on land.4. A friend says "all baby animals look like small versions of their parents." Explain why this is not always true, using an example. (2 marks)
Answer
It is not always true (1). For example, a tadpole does not look like a frog at all — it has a tail and gills and lives in water. Some animals go through metamorphosis, where the body changes shape completely (1).5. Why do you think the mother hedgehog needs to keep her hoglets warm? (2 marks)
Answer
Newborn hoglets cannot keep themselves warm (1), so without their mother they would get too cold and would not survive (1).If you want to go further
- Watch our hoglet films and see how many stages from Part 2 you can spot.
- Draw a life cycle as a circle, with arrows going round, for any animal you like.
- Related lessons: Food Chains & Habitats · Adaptation · Wildlife Explorer.
Notes for the adult
Curriculum: KS2 Science — describing the life cycles of a mammal, an amphibian, an insect and a bird, and describing the differences between them.
Why the hedgehog comes first. Starting with the simplest life cycle gives the child a baseline, so metamorphosis in Part 5 lands as a genuine surprise rather than as one more list. The note at the end of Part 2 plants it deliberately.
The word "metamorphosis" is worth the effort. It is long, and children like long words when they mean something dramatic. It is also on the KS2 curriculum.
If a child struggles with the tables, the same content works read aloud one row at a time, with the child drawing each stage. Drawing the four frog stages does the job better than reading them for many learners.
Access: read-aloud, dyslexia-friendly font, enlarged text, high contrast and calm mode. Tables are short and print onto one page.
No timing, no scoring.
Ready for more? Open the full unit →