An unusual tree frog discovered in the mountains of Vietnam

Unlike most mountain-climbers, we scale moutains not to reach the summit, but to find and scientifically document frogs!

The Trieng Tree Frog (Gracixalus trieng) is not your typical tree frog. Brown during the day, the frog brightens up at night to be pink and yellow, and instead of ponds or streams (which are in scarce supply on the steep sided mountain tops), it lays its eggs in water-filled tree holes! My colleagues and I found this frog species during expeditions in the central highlands of Vietnam and have now officially described and named it. It’s the latest scientific discovery from the incredibly biodiverse mountains of the region, home to a vast array of plants and animals found nowhere else on earth.

I have spent much of my career climbing mountains. It’s not because I want to reach the summit, and it’s certainly not because I’m good at it (all my colleagues will tell you that I’m quite terrified of heights!). Rather, it’s because I’m passionate about understanding frogs: how many species there are, where they are found, and what needs to be done to ensure their survival. And, if you are searching for frog species that are poorly-known, or even new to science, one of the best places to look is up mountains.

In the monsoon seasons of 2009 and 2010, my colleagues and I conducted expeditions in search of frogs in the high mountains of central Vietnam. Our team consisted of Vietnamese scientists, local Giẻ Triêng people and myself. Our aim was to survey the remote streams, swamps and mountain tops at night for frogs - to make sure we knew as much as possible about the frogs of these forests in the sky, particularly urgent given the rate of forest loss in the area.

From small villages, we rode motorbikes along mud tracks as far as we could, and then hiked on foot, deep into the forest. Doing our best to avoid being completely saturated by near-constant rain, we made camp by streams, sleeping in hammocks under a tarp. Each afternoon, we hiked away from camp, further up mountains, in search of frogs.

I kept a diary in a small, muddy, water-proof notebook. In it, I documented details of all the frogs that we found, as well as some accounts of the hikes, including the night that we first found the Trieng Tree Frog:

I vividly recall being frozen with fear on that hike, perched on a particularly steep section. It was then that I learnt that the phrase “I was so scared my knees were shaking” was not just a phrase! I think I’d still be there if it wasn’t for the help of my colleagues!

That night, up in the mountains amongst the bamboo and moss-covered trees, we found only two species of frog. Both looked very similar, but were equally unfamiliar to all of us. The first species was particularly unusual in that males were covered with hard, conical spikes. We scientifically named this species Gracixalus lumarius - the Thorny Tree Frog - in 2014. The second, which lacked these obvious spikes, we now scientifically name Gracixalus trieng - the Trieng Tree Frog, or Ếch cây giẻ triêng in Vietnamese. The name of this species is in honour of the Giẻ Triêng people who were a vital part of our collaborative team.

A formal scientific name is a first step in allowing us to consider this frog species in conservation decisions. We also hope that by introducing this species to the world, we can highlight the importance of the amazing highlands of central Vietnam and the creatures that inhabit them.

Dr Jodi Rowley

Curator, Amphibian & Reptile Conservation Biology, Australian Museum Research Institute & UNSW Sydney.

More information

• Rowley, J.J.L., Le, D.T.T., Hoang, H.D., Cao, T.T. & Dau, V.Q. (2020). A new species of phytotelm breeding frog (Anura: Rhacophoridae) from the Central Highlands of Vietnam. Zootaxa. 4779 (3): 341–354.