Red crabs lead the way in endurance running

Not even professional athletes would consider running a marathon without any training, but this is essentially what Christmas Island red crabs do every year, according to new research from the University of Bristol. Native to Christmas Island in the Indian Ocean, the red land crabs ( Gecarcoidea natalis ) spend the dry season relatively inactive in their rainforest burrows. When the monsoon comes, they embark on an annual five-kilometre breeding migration to the ocean. In a test of great endurance, the crabs travel for up to 12 hours over five days before finally reaching their destination. Researchers from the University of Bristol's School of Biological Science s wanted to discover how the crabs switch from hypoactivity to hyperactivity in order to carry out this remarkable athletic feat with no training. Professor Steve Morris and colleagues carried out genetic analysis on samples of leg muscles from the crabs during their migration journey and sixth months afterwards. They found that the crabs made major physiological changes to their muscle composition over a very short time to sustain aerobic high-endurance muscle for their trek to the coast.