Crucifix Frog Click to enlarge image
Juveniles. These little fellows were no more than 2 cm long when photographed. Images created at the request of Martyn Robinson. Image: Stuart Humphreys
© Australian Museum

Fast Facts

  • IUCN Conservation Status
    LEAST CONCERN (LC)
  • Classification
    Species
    bennettii
    Genus
    Notaden
    Family
    Myobatrachidae
    Order
    Anura
    Class
    Amphibia
    Subphylum
    Vertebrata
    Phylum
    Chordata
  • Size Range
    Between 4.5-6.5cm long
  • Habitats
    temporary pond
  • Life history mode
    fossorial
  • Feeding Habits
    insectivorous

Introduction

This odd-looking frog is found in the black soil plains areas and semi-arid grasslands of New South Wales and Queensland where it burrows into soil to wait for the infrequent summer and autumn rains.


Identification

A medium -sized frog with round body and relatively short limbs and large eyes. This species is easily identified by its lime green or lemon yellow skin covered with a pattern of dark spots resembling a cross.

Habitat

blacksoil plains, floodplains, clay pans and semi-arid grasslands.

Distribution

This species is found in the semi-arid region of the Murray-Darling Basin within central New-South Wales and south-central Queensland, west of the Great Dividing Range generally associated with floodplains and clay pans.



Seasonality

This species is only active after periods of high rainfall in the warmer months of the year.

Feeding and diet

This species of frog feeds mainly on ants and termites.

Other behaviours and adaptations

The Crucifix Frog is one of the few species of Australian frogs which has skin patterning that does not provide camouflage, but instead acts as a vivid warning against predation. It is not clear whether the pattern is intended to warn against a poison, or bad taste that the animal may possess, however the species and its relatives does also have glands that secrete a glue-like substance which may act as a deterrent against predators such as snakes and birds. One member of the same genus is known colloquially as the 'Superglue Frog' for this reason.

The species is common on the black soil plain areas where it buries into the clay mud around claypans and soak as the ground gets dry. Here it can remain for many month - perhaps even years - untill the rains come again from the north west. Once this happens and the ground becomes wet and soft again the Crucifix Frog can emerge from the ground and feed voriously on ants, termites, and any other small invertebrate which walks past and can be swallowed. These frogs are mainly terrestrial and are poor swimmers.

Captive inderviduals have been observed, when fed crickets, to wiggle the tips of the toes in a manner which readily attracts attention of the prey.

Prey luring behaviour has been recorded in various snakes and lizards. In amphibians such as Salamanders the behaviour involves utilising the toes and feet as the lures and is known as 'Pedal Luring'. Pedal Luring has also been recorded in some species of frogs such as the Horned Frog; Ceratophrys calcarata, from South America. See this post for more details.

Communication

Males call for females while floating spread-eagled in temporary pools. The call is a drawn out 'Hooooooooo'

Life history cycle

After sufficient rain has soaked the ground they immerge and find temporary pools where males call for the females and mating takes place. After hatching from eggs, the tadpoles grow into small frogs fast before the grasslands they inhabit dry out.

The males then seek out the waterfilled depressions, claypans and waterholes and float with their legs extended and produce a very 'owl-like' 'hooo' call. The females lay their eggs in these ponds and the tadpoles must develop within a couple of weeks before the water dries up and they perish. Being able to eat ants is a great advantage to them as the tiny metamorph Crucifix Frogs can feed both night and day on an abundant food supply ignored by most other frogs species in the area.

Predators

Very few animals are known to feed on Crucifix Frogs or their tadpoles.

Danger to humans

It is recommended that if you make contact with these frogs you are careful NOT to wipe your eyes before washing your hands. A few scientists have recorded painful stinging and headaches when they forgot to do this!

References

Anstis, M. 2002. Tadpoles of South-eastern Australia. Reed New Holland. Sydney

Cogger, H. G. 2000. Reptiles and Amphibians of Australia. Reed New Holland. Sydney.

Robinson, M. & Hosking, C. 2014. Notaden bennettii (crucifix frog) pedal luring. Herpetological Review. 45(2): 306.

Robinson, M. 2002. A field guide to frogs of Australia. Reed New Holland. Sydney.

Tyler, M.J. 1989. Australian Frogs. Viking O’Neil. South Yarra.

Tyler, M.J. 1992. Encyclopedia of Australian Animals: Frogs. Angus & Robertson. Pymble.