Mon Prof Augmenté
Warm Sand, Cool Sand
A crocodile egg’s sex is decided while it incubates, not by chromosomes like in mammals. Eggs in a warm nest often hatch as males, and eggs in a cooler nest often hatch as females.
This picture is part of the full library
Every lesson is open to everyone for 7 days after it is published. This one came out on September 12, 2026: its text stays readable here, and its picture opens with a subscription.
The app is free. A subscription opens every lesson, in every school year.
Age 12: open this week
Browse Age 12
In the picture
- Red heat waves above the left tray
- An egg in the left tray
- Blue cool waves above the right tray
- An egg in the right tray
- The broad-snouted crocodile head silhouette
Examples
- A nest dug in sun-baked sand stays warmer than one in the shade of a riverbank.
- Sea turtle eggs in warm beach sand mostly hatch as females.
Key takeaways
- Crocodile sex is set by nest temperature, not by chromosomes.
- A few degrees warmer or cooler during incubation can change whether the hatchling is male or female.
Carry on in the app
Three questions on this lesson. It has left the free week, so its quiz is for subscribers.
At least one new illustrated lesson every weekday for your child’s year, with its quiz and a reminder at 6:15 pm.
Get the app
Free app, optional subscription
App Store Google Play
