Science Fenns K-5Grades K to 5
A sea turtle hatchling crossing moonlit sand toward the glittering surf, with a nest in the dunes behind it.

Science / All lessons / Structures and Behaviors

Instinct

Turtle hatchlings find the sea.

Lesson 40 of 41

Try this first

Before we start

Today’s story

Instinct

On the Texas coast, a Kemp's ridley nest sits in the sand. After weeks, tiny turtles dig up and out. They have never seen the sea or met their mother. Still, they all crawl toward the water.

This is instinct. An instinct is a behavior an animal is born ready to do. It does not need to be taught. Turtle hatchlings head toward the brightest, lowest horizon, which is usually the open water.

Instincts help animals survive. A spider spins a web without lessons. A baby bird opens its mouth to be fed. Instinct is inherited. Here are the steps.

See it

Five steps. Every time.

    Hands on

    Light Seeker

    20 minutes · Do this with a grown-up nearby

    You need

    • a shoebox
    • a flashlight
    • small toy or paper turtle
    • tape
    • a pencil
    • dark room

    Do this

    1. Cut a small hole at one end of the shoebox.
    2. Place the paper turtle at the opposite end.
    3. Shine the flashlight at the hole.
    4. Turn the box so the light moves.
    5. Talk about how a hatchling would move toward light.
    6. Test with lights in two places.
    Write or draw: A drawing showing where the light was and which way the model turtle would head.

    Watch for: Hatchlings move toward the brightest area. A bright porch light can confuse them.

    Safety: Ask an adult to help with scissors. Do not shine lights in eyes.

    Same every time

    Three rules

    Rule 1Instincts are inherited.

    They are passed from parent to offspring.

    Rule 2They work the first time.

    No practice is needed.

    Rule 3Instincts can be fooled.

    Bright lights on shore can lead turtles the wrong way.

    Grandpa Fenn’s notebook

    Say it like a scientist

    instinct
    A behavior an animal is born able to do.
    inherited
    Passed from parent to offspring.
    hatchling
    A baby that has just come out of an egg.
    behavior
    What an animal does.

    Poppy’s quiz

    Six questions

    Tap an answer. Green means right. You will see why.

    Talk about it

    Say it out loud

    • How could you tell the difference between instinct and something learned? What evidence?
    • What animals in Texas show instinct, like migrating birds or newborn calves standing up?
    Did you know

    Scientists think a sea turtle may return to near where she hatched to lay her own eggs, and they are still working out how she finds it.

    Someone who does this

    A marine biologist studies sea animals and helps protect them.

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