Who Bites Off More than they Can Chew?

A study looking at the difference of female and male mountain dragons Diploderma batangense uncovers the different morphological traits that affect biting force performance within the species.

Batang Mountain Agama

The Batang Mountain Agama is a lizard that is endemic to the Hengduan Mountains in China and found in other various locations: eastern Tibet, northern Yunnan and western Sichuan. They have a distinctive row of spikes on either side of their spine to protect them from predators, which may give them their dragon-like resemblance.

Being a diurnal species, they would hunt for insects using their powerful jaws and bask in the sun for a much-needed power-up. To communicate between themselves, head-bobbing and colour transitions would take place as either mating or territorial behaviour.

Scientific Findings

"135 individuals were collected and seven morphological characteristics and bite force were measured". Males are larger, unusual in the herptile world, than the females in this species and this contributed largely to the end result.

A "larger head size, body size and stronger bite force" was shown by the male, compared to the female. In particular, head size proved the deciding factor and may be different due to their roles in reproduction. If the head was bigger then the jaw power would be increased therefore.

Determinants of bite force in males and females

A Head Above The Rest

The male would possibly have a larger head size for sexual selection "advantages of territorial defence and mate choice", whereas females would be "favoured by natural selection to produce larger clutches/size or egg production/offspring size" by having a bigger body size in other species.

Ecological (relation of organisms to each other and surroundings) adaptations are a force to be reckoned when trying to explain the origins. A larger head may prove to be a defining effect of hunting capability and so whoever has the biggest head will have access to more food sources.

There can be no doubt, that having a bigger head, literally and figuratively, may be a bite-sized victory in the lizard community. Future studies should be sure to take physical characteristics across different species as a possible answer to their situation.

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