Talita Bateman

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The Thorny Devil (Moloch horridus)

Few creatures are so unusual looking as the Australian Thorny Lizard. In fact, its appearance is so unusual that it received a demonised name twice - it is more commonly known as the Thorny Devil and has the scientific name Moloch horridus. Talk about a bad rep...

What fascinates me about this lizard, however, is the fact that it is a prime example of convergent evolution. British biologist William Saville-Kent, was able to predict this lizard's diet based on its morphological similarities with the North American Horned Lizard (Phrynosoma). In fact, it is said that these two species are anatomically more similar to each other than to any other members of their own families. 

All Australian lizards of the family Agamidae feed on insects. However, similarly to the North American Horned Lizard, the Thorny Devil feeds exclusively on ants. 

At first glance, one might think that the 'thorns' are a defence mechanism. Whist its appearance may or may not serve as a deterrent to potential predators, the thorn themselves are quite soft. What they do provide, however, is a way for the lizard to obtain water. As dew condenses on the spikes of their backs, it is directed to the lizard's mouth via capillary action along tiny grooves. Considering the arid areas that consist of this lizard's habitat, its natural water collection mechanism is extremely important. 

If you'd like to know more about the Thorny Devil, check out National Geographic's short video below: