ZAP’S FACTS!
REEF LIFE

Clownfish are all born male - and the boss becomes female.

When the lead female dies, the dominant male simply switches sex to replace her.

2 min read
Clownfish are all born male - and the boss becomes female.
THE FULL STORY

Clownfish live in tight little families nestled inside the stinging arms of sea anemones. Every member of the family hatches male, and they all stay male - except for one. The biggest, most dominant fish in the group turns into the female, and the second-most-dominant becomes her breeding mate. The rest stay smaller, quieter, and wait their turn.

If the dominant female dies, the breeding male takes over and physically transforms into a female. His body grows, his coloring brightens, and a smaller male moves up to become her new mate. The family carries on like nothing happened.

This makes clownfish one of the rare animals where individuals can change sex during their lives. It’s nature’s backup plan for keeping the family group going - and it makes the original Finding Nemo plot biologically very different from how it would play out in real life.

A mantis shrimp's eyes have 12 colour receptors.
DID YOU KNOW? A mantis shrimp's eyes have 12 colour receptors - but see colour worse than us. Humans see with 3 receptors. Mantis shrimp use 12. Surprisingly, scientists found they tell colours apart less precisely than we do. 2 min read
A starfish with 21 arms can destroy entire reefs.
DID YOU KNOW? A starfish with 21 arms can destroy entire reefs. Crown-of-thorns starfish eat coral - and when they swarm, the reef goes white. 2 min read
Sea turtles return to the exact beach they hatched on - using Earth's magnetic field.
DID YOU KNOW? Sea turtles return to the exact beach they hatched on - using Earth's magnetic field. Decades after leaving, a female crosses oceans to lay her own eggs on the same sand. 2 min read