The dragon that changed everything

Photo - Tess McLaren

The life of a zooloigist is often saturated with the countless spectacular photos or incredible video footage of species, often narrated by the heart -warming voice of our beloved Sir David. So much so that it is possible to feel somewhat desensitised when seeing incredible natural phenomena with our own eyes, causing us to initially take what we’re seeing for granted.

This was the case for me on my recent trip to India, where I encountered what turns out to be a rather phenomenal species of dragon lizard.

I’m not the only one to experience this feeling towards this species; there are no doubt thousands of people living in extremely close proximity to this species in its native Southern India that would hardly pay it a second look. Indeed when we were out catching these lizards using little nylon thread nooses at the end of long fishing rods, locals found our endeavors rather humorous. What would anyone possibly want with such a common lizard?

Many people are probably wondering the same thing at this point, but let me explain. Most Australian locals would be familiar with the type of dragon lizard commonly kept as pets. Docile, long lived and rather sedentary outside feeding time; bearded dragons are an excellent pet. Psammophilus dorsalis, affectionately known in the lab as Psammos (pronounced sammos) are a whole different kettle of fish. Far from docile pets, these lizards have earnt their dragon title.

Despite a diet consisting largely of ants, this species has fangs. Not large fangs, but big enough to cause researchers to have a preference for thick protective gloves when handling them. The males of this species grow as large as our pet dragons here, with females reaching just over half their size.   The suspicion that this species is short lived; completing its life cycle in as little as a year, is particularly surprising given its large body size.

Just to put that in perspective some insects have longer life cycles than these lizards.

But none of that is what brought me half way around the world in search of Psammos.

Image by Tess McLaren

These lizards change colour, spectacularly.

Above you can see a male in his relaxed yellow and black state and then, seconds later in the red and black courtship colours in response to a female, no Photoshop trickery involved. The lizard pictured above is also capable of the yellow and red colour combination depicted at the start of this post.  This phenomenal ability led to past classifications describing the different colours as different static colour morphs.  However, researchers have now found that these species can rapidly change colour from red to black to yellow to grey in response to different external triggers, all in the same body region.  Why is this exciting? Well research has uncovered the physiological mechanisms behind chameleon colour change; change that typically only involves adjustments in brightness. Complete transitions in hue (yellow to red) however, are comparatively rare making it possible that this species may have an entirely different physiological mechanism.

These fierce dragons could change everything we know about colour change!


2 Responses to “The dragon that changed everything”

  1. Tess McLaren says:

    They have four different colour states from memory, a dull blotchy grey, red and black, yellow and black and red and yellow. Each state is in response to a different context. Red and black is in response to a female – courtship. Yellow and black is a relaxed state. Red and yellow is a stressed state and also used in competition with other males (photo at top of post). Grey and blotchy would appear to be a camouflage colouration. 🙂

  2. Caitlin Selleck says:

    Great article Tess, I would love to have a colour-changing dragon.
    Is the colour-changing just a courtship display, or do you think they use it for other purposes as well?