Booming Banded Bullfrogs of the Burbs

The rain had been falling steadily all day. Still the clinging heat persisted. If anything, the humidity levels had risen as the rain evaporated from the hot concrete. Perhaps I could find cooler air on a night walk around the neighbourhood. The drains and canals were gushing water and large warm puddles turned the urban fields in to swamps.

As I walked alongside a shallow covered drain a deep booming sound came reverberating up from the concrete tunnel below. It was the unmistakable sound of the Banded Bullfrog.

Banded bullfrog

The Banded bullfrog is a common frog in this part of the world. It may not cause a flutter of excitement in many people, but for me this was a magical moment. The Banded Bullfrog was one of those exotic amphibians that was available in pet shops in the UK when I was a kid. Of course, I had kept them, rather unsuccessfully, as pets so the idea of seeing them in the wild was thrilling. I peered through the iron grill into a drain. The honking stopped. No trace of my bullfrog. I fished a torch out of my bag and scanned the field. Finally, my beam landed on a butterball of chocolate and caramel. There on the edge of a drain was my first ever wild Banded Bullfrog.

An urban Banded Bullfrog in Singapore

I laid down on the wet path and focused on the glum little face. Without discernible movement or change of expression a tongue darted out and mopped up a large ant. This plump female was keeping her distance from the booming males below.

A Banded bullfrog slurps up an ant

I walked around the area to see what else I could find. I could hear the croaking of Asian toads, Chorus frogs, and bullfrogs so I walked towards the sounds while scanning around my feet to make sure I didn’t step on something.

Juvenile Banded Bullfrog

There was movement! A bounce at my feet as a Banded bullfroglet boinged on to a wet leaf. This was the first time I had seen a juvenile. It was always adults that were for sale in the British pet shops. At around 2 centimetres in length, the juvenile was perfectly formed with is adult colouration.

The froglet disappeared into the grass and my torch flashed around before landing on a glimmering bump on a tree trunk. I couldn’t believe my eyes – a young bullfrog was climbing the tree with ease, as it followed a column of ants up the trunk, gulping one down every few seconds. I am used to seeing long limbed elegant tree frogs prowling up any vertical surface, but I was amazed to see this chubby little short limbed amphibian walking up a tree with ease.

A young Banded Bullfrog follows a column of ants up a tree

The adult Banded bullfrog has a body that appears to be almost rounded. When feeling threatened or while croaking for a mate the frog blows itself up to something that puts us in mind of a brown tennis ball. It is around 7 centimetres in body length with features that include short stumpy legs, large toe pads on the front feet, and big eyes. Differences between sexes are small, but during the breeding season the males throat or vocal sack becomes dark.

Despite being prevalent across the region it is believed that the species was introduced to Singapore. Possibly first brought to the country as a source of food, it has been a resident of suburbia for over 100 years. Happily, impact assessments have not been able to identify any negative impacts from their presence in the country.

The croaking started up again and this time it was coming from a large shallow puddle. I walked towards the cacophony. A competition seemed to be breaking out between the bullfrogs and the Asian toads. The persistent monotone low honk of the bullfrog vs the urgent high pitch machine gunning of the toads.

An urgent Asian Toad

My torchlight fell on the puddle and everything fell silent. Now the only sounds were the distant calls of a nightjar and the whine of opportunistic mosquitoes that were teasing my ear. The air was now so heavy with water that stinging streams of sweat were trickling into my eyes. I waited patiently while I looked for movement or a sound in the illuminated puddle. There was a splash to my left as two male Asian toads that had been eyeballing each other finally decided to wrestle it out. Then, as if relaxed by the broken silence, a cow-like moo came from my right.

Banded Bullfrog calling for a mate

There was the sight I had hoped for! A good sized male Banded bullfrog was inflating his body like a ballon before squeezing the air rapidly into the vocal sack, creating another balloon. The vibrations caused by rapid transfer of air caused ripples to spring in circles away from the frog’s body.

Huge Banded Bullfrog vocal sack

The dark vocal sack was swollen close to bursting, revealing a galaxy of white star speckles before shrinking back down to loose skin as the air refilled the frog’s body. The process was repeated again and again. Occasionally another nearby male would respond and my guy would reply by redoubling his efforts, closing his eyes as he squeezed out another mighty moooo.

A bellowing Banded Bullfrog in a Singapore puddle
Banded Bullfrogs croaking in a puddle

Following a stormy night, the ponds and temporary puddles were covered by a single layer of floating spawn. Under the hammer of the equatorial sun these puddles heat up like bath water and dry fast. The tiny eggs start to develop immediately and within 48 hours the tadpoles break free to start their race against the weather. They must hope for more rain to top up the pools before they dry up.

A thin floating single layer of Banded bullfrog spawn
A male Banded Bullfrog waits for a partner beside a raft of bullfrog spawn

It seems like a risky strategy to race the equatorial sun and bet on the fickle rains of an island nation, but the growing Banded bullfrog population and an abundance of froglets is testament to the success of this strategy.

The scientific name for the Banded Bullfrog is Kaloula pulchra. The word pulchra means “beautiful” in Latin. I wonder if the naming was due to the obvious beauty of the frog’s patterns and colours or perhaps it was a little humour from the namer, who was surely enchanted by that narrow and somewhat miserable looking mouth.

I have seen many Banded bullfrogs since arriving in Singapore. I always stop for a close-up look when I see one. I often head out with a torch on a wet night, and I never take a sighting for granted. For me, this harmless chubby frog, nemesis of ants, definitely wears its name well. A real beauty!

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Categories: Asia, SingaporeTags: , , , , , ,

David

I am a wildlife blogger and traveler, using images & stories to inspire wild connections.

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