Friday, December 24, 2010

Merry Christmas!

How fitting is it that the most wonderful time of the year has its own island (Christmas Island) and that island is also called “the kingdom of the crabs” and “the crabbiest place in the world”? Two happier things couldn’t be combined!

Coconut crab (Birgus latro)
(photos from

Christmas Island red crabs (Gecarcoidea natalis)
heading to sea

Christmas Island is home to 20 terrestrial and intertidal crabs, including coconut crabs (a personal favorite: I’ve seen these guys in the Solomon Islands) and red crabs. The latter are famous for their massive march to the sea from their jungle home:

(I strongly encourage you to watch all the National Geographic videos on the red crab migration [millions of crab babies!!], but I’ll warn you now: you will come to hate yellow crazy ants!)


Red crabs undergo an incredible physiological change when embarking on their journey: they have to get their muscles from couch-potato to marathon-runner, which involves changes in their gene expression (rather than an 18 week training program. Lucky!). Scientists from the University of Bristol just published an article on red crab leg muscles, and it is covered quite splendidly here.

I’ll leave you with my take on a Christmas Island Christmas tree:


Red crab reading:
Postel, U., F. Thompson, G. Barker, M. Viney, and S. Morris. 2010. Migration-related changes in gene expression in leg muscle of the Christmas Island red crab Gecarcoidea natalis: seasonal preparation for long-distance walking. Journal of Experimental Biology 213: 1740-1750.


  1. You're hilarious. Are red crabs cannibals?! (Just watching the video, see 0:57)..

    1. Yes, red crabs are cannibals Kat. They will eat small insects and snails, and even garbage given the chance!

  2. Yeah Kat, it looks like it! A lot of crabs (maybe all?) are cannibalistic. And really, can we blame them and their tastey legs?

  3. A blog for crabs! Fair play. Long live the Snow Crab!