University of Bristol: Student helps find world’s largest frog in Equatorial Guinea for first time in almost two decades

The most recent amphibian survey in the country’s Monte Alén National Park, which is one of the goliath frog’s few known habitats, recorded no sign of it.

Goliath frogs can be as big as some housecats, measuring up to 34cm in length and weighing more than 3kg.

Concerned by the lack of recent evidence of the species in the national park, conservationists travelled to Equatorial Guinea to find evidence that the giant amphibian was not lost to the region.

Working in partnership with INDEFOR-AP, the national park service of Equatorial Guinea, the researchers conducted a survey along the Benito River.

Over 10 days in the forest, the researchers spotted the amphibian in a small waterfall. They had hoped to collect vocal recordings of the frog, however, the animal was not heard calling, perhaps confirming previous accounts that it is indeed a quiet, if not silent, amphibian. More study is needed.

Sam Hurley, Biological Sciences masters research student at the University of Bristol, said: “A few weeks before this trip, we had carried out a survey on the other side of the national park and were unable to locate any of these incredible creatures.

“This dampened our hopes of finding the goliath frog in Equatorial Guinea, so to then spot over 10 individuals across multiple nights was incredibly heartening.

“The frogs were very sensitive to noise, and they were all found along the same short stretch of riverbank, close to a waterfall.”

Dr Gráinne McCabe, head of field conservation and science at Bristol Zoological Society, said: “When the team came out of the forest they were overjoyed to share the news. This incredible frog hasn’t been officially confirmed in the national park by INDEFOR-AP for almost two decades.

“However, it was only seen in one small section of the survey area, indicating it needs to be better protected. Now that we know the species has not disappeared, we can study the amphibian in more detail, monitor its presence and help protect this endangered species.”

The goliath frog has been around for more than 250 million years and is one of only a few amphibians still alive that lived on Earth before dinosaurs. The species is classified as Endangered on the IUCN Red List.

The species is Endangered due to being over-hunted for food. They have also been hunted as trophies and for the pet trade. The goliath frog is also at risk due to loss of habitat, with continued deforestation, farming, logging and the expansion of human settlements.

Results from this study will now be used as a baseline for establishing a long-term monitoring programme in the national park for the goliath frog, and to determine recommended actions to address the decline of this species in Equatorial Guinea. The species is also found in limited areas in Cameroon.

Bristol Zoological Society and University of the West of England (UWE Bristol), have been running a joint field conservation programme in the area around Monte Alén National Park since 2018, to protect western lowland gorillas and more recently, help reduce conflict between local villages and the national park, due to fear and frustration over forest elephants that are entering villages and farms to forage on people’s crops.

In 2021, Sam Hurley joined the team to undertake a much needed amphibian survey of the national park and surrounding areas.

The survey work was carried out in close collaboration with field researchers from INDEFOR-AP. The goliath frog survey was supported by Mohamed bin Zayed Species Conservation Fund and SAVE THE FROGS!, a US-based charity.

Bristol Zoological Society is a registered charity which owns and runs Bristol Zoo Gardens and Wild Place Project.

The Society also directs 34 field conservation projects in nine countries that conserve and protect some of the world’s most threatened species.

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