KOTA KINABALU: A new study has revealed that using traditional scientific methods to determine the number of wild reticulated pythons in the jungle are nearly impossible.
Despite five years of intensive surveys along Sabah’s Kinabatangan River, researchers found the snakes are so well camouflaged and elusive that using Population Viability Analysis (PVA) cannot reliably estimate their numbers.
Because of this, experts say conservation rules should stop relying on field counts to set harvest limits and they recommend monitoring pythons captured for trade to check on their size, health, and sex ratios over time to assess whether the harvesting is sustainable.
The landmark findings, published in Scientific Reports, suggest that international regulators such as CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) monitor data from commercial processing facilities - tracking trends in harvested specimens including its size, sex ratios, body condition to ensure long term sustainability of the trade.
The study, which focused on wild python populations across Sabah's eastern Lower Kinabatangan Wildlife Sanctuary (LKWS) and nearby oil palm agricultural landscapes, uncovered critical insights into python detectability, behaviour and population dynamics.
Conducted from April 2016 through March 2021, researchers completed 527 nocturnal riverbank boat surveys, covering a total distance of 2,427km along a 64km stretch of the Kinabatangan River.
The intensive survey effort targeted unharvested python populations living at its natural carrying capacity.
The main finding of the study was that pythons proved remarkably elusive. The overall mean detection probability was just 20.5%, with individuals remaining undetected 25% of the time even in habitats where their presence was definitely confirmed.
Danau Girang Field Centre (DGFC) director Dr Benoit Goossens, who was among the researchers, said that even under ideal ecological conditions and with a massive sustained field effort, it was impossible to get reliable numbers on how many of these snakes are out there or how many die naturally.
He said the pythons were too well hidden and even trying to use field surveys to set harvest limits just did not work.
International Union for Conservation of Nature (IUCN) Species Survival Commission (SSC) chair for the snake specialist group and co-author of the study Dr Daniel Natusch said that with the study completed, it gives them the best way to use limited resources to keep track of and manage species like reticulated pythons.
“Our findings directly challenge policies that demand field-based population estimates before permitting commercial trade. We emphasise that international policy decisions such as CITES regulations or trade quotas should not rely on unfeasible field population models,” Natusch added.
Goossens said they were advocating for tracking long-term trends from specimens harvested by commercial processing facilities in active trade regions.
“Monitoring consistency in parameters such as body size distributions, body condition, and sex ratios over time serves as a far more reliable, realistic, and responsive benchmark for determining whether trade levels are sustainable,” Goossens said.
