Paul Chan observed that when male face-banded crabs win a fight against other crabs, they scrape one claw against the other to make low-pitched rasping sounds.
Face-banded crabs or Perisesarma eumolpe, named for the bright blue-green band across their fronts, live in mangrove swamps in Mandai and Sungei Buloh.
Paul Chan, a National University of Singapore (NUS) undergraduate found that the crabs do this to show off their size and prowess to warn off potential challengers, .
For the project, Mr Chan combined high-tech acoustic analysis of the crabs' sounds with 'old-fashioned field work, staring at crabs in the mud and chasing after them', said his adviser, NUS biology Professor Peter Ng.
'Paul is smart...to join the two and use them to better understand a phenomenon mooted decades ago but never proven. And the work has also challenged conventions on what the sounds do and how crabs register sound,' Prof Ng said.
Mr Chan, who graduated this week, will be doing his PhD at NUS, also likely on face-banded crabs. 'By looking at animal behaviour, we can learn about ourselves' in areas such as communication, he said.
For more see When crabs perform their victory dance, Grace Chua, Straits Times 11 Jul 09 on the wildsingapore news blog.