This little lizard survives its time in the sun by operating at the very limit of thermal tolerance for a vertebrate.
Life on the edge
W
HEN I recently visited
the Australian Age of
Dinosaurs museum in
central Queensland, the temperature
hit 42°C. Shade offered little
sanctuary, but exposure to direct
sun, where the conditions were
up to 10°C higher, was potentially
lethal. Yet this tiny, smooth-snouted
earless dragon (Tympanocryptis
intima) chose to bask in full sunlight
on a black metal chain atop a
concrete post. For me the chain
was too hot to touch for even a few
seconds. By careful posturing andstrategic colouration a baby dragon
like this, with a head and body
length of just 2cm, can avoid
cooking in conditions that would
kill anything else. Those skinny legs
are holding its body high off the
hot metal, while its white underside
helps deflect heat radiating from
below. I’m not sure why it wasn’t
tucked away under a shaded stone.
There was no available food, and it
was too hot even for ants. And it
was probably too young to have a
territory that needed guarding.
STEVE K. WILSONbuzz
May. June 23