Madeleine Yewers


Populations of tawny dragon lizards found in the Flinders Ranges are colour polymorphic. Males in these interbreeding populations are found in four discrete throat colour types, orange, yellow, grey and orange/yellow. I am investigating the function of the male colour morphs as well as their evolutionary significance.

The four morphs of the tawny dragons

The four morphs of the tawny dragons

Throat colour of orange morph

Orange morph

To investigate function I am measuring morphological, ecological, physiological and behavioural traits of male morphs in the field. This includes measures of immune function, hormone levels and aggressive behaviour using fake lizard models to simulate territorial intrusions.  Individuals are also permanently marked using elastomer implants so over the years I can measure survival and frequencies of morphs.

Model presentation (grey morph) to male

Model presentation to male

Photo by Enrico Cruz

Photo by Enrique Cruz

Contact: m.yewers[at]