The Clouded Monitor and the Banded Bullfrog

on 5th July 2014

Johnny Wee encountered a Clouded Monitor (Varanus nebulosus) in Singapore’s Venus Drive in May 2014 (above). Clamped tight in its mouth was a Banded Bullfrog (Kaloula pulchra). The bullfrog was countering the monitor’s attempt at swallowing it by inflating its body. For 15 minutes the monitor tried its utmost to swallow its prey but failed. It eventually gave up and the bullfrog went free.

Banded Bullfrogs are not native to Singapore. Commonly sold in pet shops, they are regularly released in our parks and forests during certain religious occasions.

This is what Dr Leong Tzi Ming has to say when shown the image:

“Clouded Monitors typically scrape away the top soil of the forest floor in search of earthworms and insects with the help of their keen sense of smell. This particular Banded Bullfrog may have been inadvertently excavated by the monitor lizard as it was foraging.

“However, what appears to be a spongy and juicy meal actually turned out to be as tough to tackle as a slimy rubber ball! When attacked, the Banded Bullfrog is capable of secreting noxious and sticky slime all over its skin, plus inflating its body in self defence.

“Habitually, male Banded Bullfrogs will inflate themselves when they feel the urge to breed after heavy rains (above).

“The air is then transferred from their lungs to inflate the balloon-like vocal sac to produce its characteristic bellows (above).

“A video clip of a male calling (documented by Leong Tzi Ming in December 2012) may be previewed below.”

Johnny Wee (top image) & Dr Leong Tzi Ming (other images, video)
June 2014

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

Other posts by YC Wee

2 Responses

  1. Actually, it’s the American Bullfrog (Lithobates catesbeianus) that is sold in pet shops (as live food for carnivorous fishes) and in markets for human consumption, and finds its way into nature areas through release by humans. The Banded Bullfrog on the other hand, is not thought to be native, but has been well-established for more than a century without any apparent ecological consequences.

  2. Amazing! I thought that the monitor’s mouth would still have been big enough to accommodate the inflated frog! Guess I was wrong!

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