From biting to body raising: Study shows two distinct defensive behaviours in Indian frogs

New Delhi: Indian frog hunters have reported two distinct defensive behaviours in frogs, revealing how much still remains to be discovered about the natural history of these amphibians.

When threatened, a species found in Arunachal Pradesh can bite and release a shriek while another from Kerala raises its body to intimidate the enemy.

Frogs exhibit a wide array of defensive mechanisms to reduce predation risk, from avoiding detection to counter attacking when threatened.

Of the 7,876 known species globally, around 650 reportedly display such behaviours, including biting and body-raising.

However, these natural history observations are seldom documented in Indian species.

A Delhi University team has now described two previously unreported anti-predator behaviours in Indian frogs in their study that details a biting response accompanied by a unique warning call in the Apatani Horned Toad and a body-raising display in the Bicoloured Frog.

“These are the first records of biting and body-raising as defensive strategies among India’s 419 known frog species,” said team leader S D Biju, an internationally known researcher on Indian frogs.

The nocturnal Apatani Horned Toad, endemic to Arunachal Pradesh, relies on its cryptic, leaf litter-like colouration to remain undetected during the day.

When threatened or approached, it inflates its body, emits a sharp call, and may even bite the intruder—behaviours first noticed during field photography and later confirmed experimentally using a twig as a simulated threat.

The Bicoloured Frog, endemic to the Western Ghats and easily recognised by its strikingly contrasting dorsal and ventral body colouration, shows a different behaviour.

This species is diurnal and can be found on the forest floor among leaf litter. When disturbed, it extends its limbs vertically, lifting its body off the ground in a posture thought to make it appear larger and more intimidating.

Such a “body-raising” display was observed during photography in the wild and subsequently tested using a threat stimuli.

“A variety of defence behaviours are known in frogs, but they are not as frequently reported. These new observations in Indian frogs are just an example of how much about the natural history and behaviours of our native species remains either undocumented or completely unknown.” said Biju.

The study has appeared in the latest issue of the journal Herpetological Notes.