Mohamed bin Zayed Species project number 192521684

The Population of Borneo Monitor Lizards (Steindachner, 1878) in Serimbu Village, West Kalimantan

The earless monitor lizard (Lanthanotus borneensis) is a unique, rare, and endemic monitor lizard species on the island of Borneo. Monitor lizards are threatened with extinction because apart from habitat destruction such as opening oil palm plantations, agriculture (Curran et al. 2004), and illegal gold mining (Yaap et al. 2012), they are also hunted by some local people and sold as pets. Illegal trade cases of  L.borneensis have reached an international scale with the highest prices being offered by the USA, Japan and Germany (Nijman and Stoner 2014). L.borneensis is only distributed in the lowlands of Borneo, specifically West Kalimantan, East Kalimantan, and Sarawak (Malaysia) (Langner, 2017).

Data collection was carried out in September 2020. Our efforts are to conduct interviews with local communities as well as direct field observations. Based on the results of interviews with 25 people that we conducted. Most said they did not know L. borneensis and had never encountered it. There was one person who said he had seen it in nature, but that was about 5-10 years ago.

After conducting interviews without results, we made direct observations in the field in Sekuju Stream, Serimbu Village, which still has a primary forest. We traced five small creek which are branches of the Sekuju Stream. We use the VES (Visual Encounter Survey) method in combination with a line transect. We carry out intensive disbursement for a week at any time of the day or night. During the day we carefully turned over any large rocks and weathered logs and litter to look for L.borneensis. We encountered several illegal logging camps during our survey and interviewed some of them. Some say that a few days ago their hunting dogs caught an animal similar to the picture we show (L.borneensis) and they ate it together with a monitor lizard (Varanus salvator). They also showed the processed monitor lizards which had been fermented. It is difficult for us to believe this discovery because only pieces of monitor lizard tails that have been slightly decomposed due to the fermentation process are visible.

Based on the results of measurements of environmental factors such as water pH, humidity, and temperature of water and air. In general, the condition of the forest that we explored is still in good condition and is still in accordance with what is stated in the literature. However, Lanthanotus borneensis has not been found at that location.

The other fauna found around the observation site that has the potential to be a choice of feed for Lanthanotus borneensis are crabs, Pheretima sp., Pontoscolex sp. Macrobrachium sp., and Ichthyophis sp. as well as several types of fish such as Rasbora spp., and Channa lucius. In addition, several fauna were found that could become competitors for L.borneensis such as Xenochrophis trianguligerus, Tropidophorus micropus, and Dogania suplana. Other herpetofauna found were Gonocephalus grandis, Phrynoidis juxtasper, Leptobrachela mjobergii, Odorrana hosii, and Chalcorana chalconota.