A new study solves a longstanding mystery surrounding the crabs: how the the normally sedentary species has the stamina to “undergo one of the most arduous migrations on Earth,” in the words of study co-author Lucy Turner.
When the wet season blows intoÂ Christmas Island (map) each year, millions of Christmas Island red crabs hike for several days, from a high rain forest plateau down to Indian Ocean beaches, where the crabs mate in burrows.
“It’s an amazing featâ€”going from not being able to exercise for more than ten minutes to walking for several miles,” said Turner, a biologist at the University of Bristol in the United Kingdom.
But by sampling circulatory fluidâ€”the equivalent of bloodâ€”from migrating crabs, Turner and colleagues discovered that a surge in the crustacean hyperglycemic hormone works with glucose, an energy-producing sugar, to fuel the epic trek.
The crab’s endocrine system also regulates the ability of the crabs to access glucose from their energy stores, Turner added.