Exploring the Python Dichotomy

From the Orianne Society, 5/5/12

A Tale of Two Populations: Burmese Pythons of Bangladesh May Be Dwindling in their Native Environment While Thriving as Invaders Half a World Away in the Everglades

Author: Shahriar Caesar Rahman,

Department of Environmental Science, Independent University, Bangladesh and Center for Advanced Research in Natural Resources and Management (CARINAM), Bangladesh.

Burmese pythons (Python molurus bivittatus) in the Florida Everglades have been the subject of intensive scientific study and media scrutiny in recent years as concern grows about their impact as invaders. It is suspected that the non-native pythons pose a serious threat to native ecosystems in Florida, not just in their current range but far beyond. The impact of pythons and their potential range expansion in other parts of the United States is not clearly understood, partly because of a lack of knowledge concerning their ecology and behavior in their native range.

A half a world away, Burmese pythons remain one of the least-studied python species on the planet. Despite their tremendous popularity in the pet industry, Burmese pythons in native Asia are something of a mystery. Drastically understudied in almost all aspects of their biology, very little is known about the Burmese python, their ecology, and natural history in Asia.

Published knowledge on the ecology and behavior of free-ranging Burmese pythons in their native range is limited to studies of their basking and breeding behavior in Keoladeo National Park, Rajsthan, India; a 24-day radio telemetric study of a single individual in Hong Kong; and incidental natural history observations. Detailed field study on Burmese pythons is long overdue.

With that in mind, our research team embarked on a field study of Burmese pythons in Bangladesh's Lawachara National Park in May of 2011 with initial financial support from The Orianne Society and The Explorers Club.

Both subspecies of Asian rock pythons, Indian Python (Python molurus molurus) and Burmese Python (Python molurus bivittatus), occur in Bangladesh. Once common throughout the country, pythons are now fragmented into small and disjunct populations. They are now mostly found in the Sundarban mangrove forest in the southwest and the mixed-evergreen forests in the northeast and southeast of the country.

Habitat destruction is one major cause of their decline. Indiscriminate killing — out of fear or for consumption — is another.

Lawachara National Park, a 1,250 hectares mixed-evergreen forest, located in the northeast of Bangladesh, falls within the Indo-Burma Biodiversity Hotspot, which supports some of the most unique and diverse biota on the planet. Most of the original forest cover has been altered or substantially removed by rotation since the early 1900s, with only some small, remnant patches of primary forest left inside the park.

During our first year of study, we conducted intensive field surveys in this forest-plantation mosaic landscape to collect baseline data on the python population and create a base for a longer-term ecological study. Our research team also spent hundreds of hours in the field and systematically documented more than 500 individual snakes and identified 35 snake species from Lawachara National Park and the surrounding tea estates. Several of the snake species were recorded for the first time from Bangladesh.

Despite the adversity herpetofauna may be facing—from indiscriminate killing, road mortality, deforestation, and degradation of the habitat—Lawachara appears to be a snake hotspot in this region.

Surrounded by tea plantations and human habitats on almost all sides, Lawachara pythons are opportunistically captured and consumed by the indigenous tribal people living adjacent to the forest. Pythons are also often found on the tea estates, particularly in porcupine and pangolin burrows. During our survey, we found an abandoned python nest as well as four python hatchlings in different parts of the tea plantation, indicating that pythons use the plantation areas for breeding purposes.

This summer, we plan to implant radio transmitters and miniature temperature loggers on several adult pythons to collect data on movement, ranging patterns, and thermal preference of free-ranging pythons.

One of our future research objectives is to answer some important scientific questions: How do pythons react to thermal variation throughout the year? How much time do they spend basking in winter, and do they use different areas of their activity range in cool months versus warm months? How does thermal biology affect detection probability?

The knowledge gained from this study could be crucial for many reasons. Any information that sheds lights on the natural history and ecology of pythons could provide knowledge to help understand their impact on the Everglades and potential range expansion in North America. Our study site in Bangladesh is at nearly the same latitude as southern Florida, which could allow for the collection of useful comparative data to help understand the invasion process.

Also, Burmese pythons are considered Endangered in much of their native range. The lack of basic information makes conservation and management decisions difficult at best, and possibly inappropriate. Collecting information about their home-range size, habitat use, thermoregulatory behavior (e.g. basking) and other aspects of life history will be vital for conservation and management of this species in Bangladesh or anywhere in their native range.