The crucifix frog looks a little frowny. (CREDIT: © Dr Paul Anthony Stewart, Sydney University; Flickr username Paulhypnos)

Crucifix frog has nothing to frown about

  • October 16, 2014

This quite serious looking frog, often mistaken for a toad, would put a frown on any predator with its gooey defence

Contributor
Becky Crew

Becky Crew is a Sydney-based science communicator with a love for weird and wonderful animals. From strange behaviours and special adaptations to newly discovered species and the researchers who find them, her topics celebrate how alien yet relatable so many of the creatures that live amongst us can be.

LOOK AT THIS fat little guy. No one has more personality than this warty, ping-pong ball of a guy. He's a crucifix frog (Notaden bennettii), native to western New South Wales and south-western Queensland.

The crucifix frog (often called a toad) is decorated with a striking black, red, and green cross-shaped pattern that runs all the way across its bright yellow back, as you can see below.


Looking at the back of the crucifix frog, you can see how its name came about. (CREDIT: ©Dr Paul Anthony Stewart/Flickr: Paulhypno) 

Obviously these colours wouldn't do much to help the crucifix frog camouflage against the blackish flood plains it lives on - quite the opposite, they're there to make the frog stand out.

The crucifix frog is one of the only species of Australian frog to employ aposematism, which is the use of bright patterning to ward off predators.


Crucifix frogs are quite small, measuring only about 4.5-6.5cm.  (CREDIT: Wikimedia) 

Crucifix frog uses sticky 'glue' for defence and capture

There's no evidence that the crucifix frog is poisonous like other brightly coloured species, but it does ooze a milky, sticky 'frog glue' from glands in its skin when threatened. According to the Australian Museum, it has a close relative with the same ability, and it's been nicknamed the 'superglue frog'.

The purpose of the frog glue could be twofold. If something tries to take a bite out of a crucifix frog, they'll get a mouth full of goo and know not to try that again.

If these bites happen to come from something as small as flies or ants, there's a good chance they'll get stuck to the skin thanks to the frog glue. The crucifix frog will then shed its skin and eat the whole thing, bugs and all. Which is so gross, yet so incredibly efficient.

The crucifix frog lives most of its life in underground burrows two or three metres deep, and only comes out after bouts of heavy rain. At this point they'll go into a feeding and mating frenzy, reveling in the temporary pools formed by the downpour. Thick with bugs, worms, and mosquito larvae, these pools are like an incredibly rich and nutritious soup for the frogs.

They really don't have to do much to capture their prey at this point, but if their 'soup' ever runs out, the crucifix frog has another strategy for snagging a meal - toe waggling. It's the best and laziest hunting mechanism ever: