Question 1

True or false: Christmas Island crabs are found only on Christmas Island in the Indian Ocean.

Accepted Answer

False. They are endemic to Christmas Island and the nearby Cocos (Keeling) Islands, but the vast majority live on Christmas Island.

Question 2

True or false: Christmas Island crabs migrate to the ocean by the millions each year to breed.

Accepted Answer

True. Over 50 million red crabs migrate annually from forest to coast for spawning, timed with the wet season's first rains.

Question 3

True or false: Christmas Island crabs are the only land crabs that can breathe underwater indefinitely.

Accepted Answer

False. They cannot breathe underwater; they hold air in their gill chambers and must return to land or drown.

Question 4

True or false: Yellow crazy ants pose a major threat to Christmas Island crabs by spraying formic acid.

Accepted Answer

True. Invasive yellow crazy ants blind and kill crabs with formic acid sprays, devastating local populations.

Question 5

True or false: The crabs' migration is triggered by a drop in atmospheric pressure from an approaching cyclone.

Accepted Answer

False. Migration is triggered by the onset of the wet season's first rains, not by pressure changes alone. Cyclones can disrupt it.

Question 6

True or false: These crabs can climb trees and eat baby birds alive.

Accepted Answer

True. They are opportunistic omnivores and have been documented climbing trees to prey on seabird chicks and fallen fruit.

Question 7

True or false: The crabs' bright red color comes from a pigment that also protects them from UV radiation.

Accepted Answer

True. The red pigment (astaxanthin) acts as a sunscreen, shielding them from intense tropical sun during their open migration.

Question 8

True or false: These crabs can regrow lost claws and legs within a single molting cycle.

Accepted Answer

False. Regeneration takes multiple molts over months to years; a single molt only produces a small, non-functional limb bud.

Christmas Island Crab Trivia Questions