Tuesday, May 8, 2012

Travel With Crabs: Oahu


Our first destination is Oahu, Hawaii. My husband Adam had the opportunity to travel to Oahu and work at the University of Hawaii at Manoa lab processing Steller sea lion blood samples. When not working, he headed to Waikiki Beach and spotted these little guys:

A'ama
Grapsus tenuicrustatus

I love their green spots!

there are 4 a'ama crabs in this shot!

A'ama has several other common names including the lightfoot crab (kind of like Sally Lightfoots seen here) and the weak-shelled shore crab. They are an important crab to Hawaiians who enjoy catching and feasting on them either cooked or fresh and raw! To quote [a translation of] the song "E 'A'ama":

"Run, run, you must run away
Run, run, here and there
I will catch you, black crab
You are delicious!"

"I'd like to see you try!" - a'ama crab

Run these crabs will! They are built for running on land and in the water, and maintain different postures to gain greatest efficiency in either environment. That's why they are so fit for intertidal habitats and are often found on lava rocks ducking from the waves.

two crabs at a tide pool

Keep an eye out for these black beauties the next time you're in Oahu! And if you see a bright red version seemingly sunning itself on the rocks, it just may be a molt for you to treasure!

Run, a'ama, run:
Martinez, M. M., R. J. Full, and M. A. R. Koehl. 1998. Underwater punting by an intertidal crab: a novel gait revealed by the kinematics of pedestrian locomotion in air versus water. Journal of Experimental Biology 201: 2609 - 2623.

Martinez, M. M. 2001. Running in the surf: hydrodynamics of the shore crab Grapsus tenuicrustatus. Journal of Experimental Biology 204: 3097 - 3112.

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