Turn on the sound (video below) to hear the soft screech of a dinosaur. This sleeping male frilly decided to hold his ground for a while, flaring his frill and lashing his tail repeatedly. For large males I usually wear gloves in case I’m not able to grab them the right way initially. Frillies have large skulls with musculature in the lower jaw both for deploying their frills and delivering a powerful bite. This is what I’m up to almost every night here in the Top End – just getting a few tail whips to the face occasionally!
I’m testing whether frills are used as a deimatic signal, particularly color, and examining the behavioral sequence after introducing a model predator. All the frillies I’ve found have three large frill folds with bright red-orange coloration restricted to the region between the folds, so when the frill is folded the coloration is concealed. But there are many frill regions with different colors (especially the back of the frill which came as a surprise to me), so I’m developing an extensive data set with a spectrophotometer… a lot is going on in their frills! I’m also looking at differences in frill size and color between the sexes for the frill’s potential role in sexual selection – there have been some behavioral studies on male-male competition.
Handled with appropriate permits for scientific study; photographed after capture [5]