The abandoned railway station in Katerniaghat, near the border with Nepal, looked like a movie set of a bygone era. The dilapidated waiting rooms were filthy with the accumulated debris of several decades.

In one of the rooms, Rom picked up pieces of leathery, brown parchment from the floor. “Python eggs,” he declared. He swung around and looked out through the doorway. I followed his gaze and thought: “Uh oh.” Tall, raspy grass stretched down the gentle slope to a swamp overgrown with Ipomoea, a South American plant.

I plunged into the grass after Rom; it was almost my height. If I didn't keep up with him, the vegetation swung back like a curtain and covered his tracks. The blades of grass sliced my hands as I held them out to protect my face. I was probably small enough to be python food, I thought with discomfort. But it was too late to retreat now.

When we emerged onto the swamp, Rom began looking around. He held up his hand signalling me to stop. Something plopped into the water not far from us.

The spindly, rangy Ipomoea grew in a tangled mass and cradled the basking pythons well above the water. As an added bonus, when predators or snake hunters such as Rom arrived, the vibrations passed along the lattice work of plant stalks for several yards, like telegraph, alerting the sunbathing snakes. Long before we got close, we heard the crackling of dry twigs followed by the sound of a snake slipping into the water.

We stood still, wondering how to find a python, when one found us. A large snake approached Rom, flicking its tongue at his heels curiously. Its eyes were cataract opaque; it would go into skin-shedding mode in a few days. Usually snakes in this vulnerable stage of blindness hunker quietly in a dark hollow.

Without wasting a minute, Rom picked it up. He wanted to check if this was Indian or Burmese rock python. They are both the same species but with a few differences. Rom ordered, “Check the suboculars.” I looked at the ring of scales around the eye in bewilderment. Rom was having a hard time controlling a squirming 12-ft snake, so I was on my own. I looked for other distinguishing characters.

The python had a clear arrowhead marking on the top of its head, the tongue was blue-black, and the face had no hint of pink. All signs of a Burmese rock python. When Rom released it, it shot through the thicket with a speed that belied its bulk. I felt certain that the snake would never make the mistake of approaching a human again.

We stood little chance of finding any more pythons in the swamp. That evening we returned to investigate the abandoned railway station. In one room, we not only found pieces of eggshell but numerous tracks of baby snakes etched faintly in the dust. For more than a century, pythons were slaughtered countrywide for their skin, and now, more than three decades after the ban, they were obviously doing well in some places at least.

Burmese pythons are also flourishing on the other side of the planet, in the Everglades of Florida. They have gained a notorious reputation as predators of local mammals, alligators and birds. The seed population was probably released by irresponsible pet owners. Snake hunters and wildlife officials kill every python they see, but it's debatable if they'll ever be rid of them.

In Katerniaghat, however, the snakes rely on a foreign species for their protection. To a purist, Ipomoea may be an eyesore that ought to be removed from a protected sanctuary. No doubt, it supplants local species that would have benefitted a greater number of creatures. However, until a native replacement is found, the Latino alien provides refuge to this population of Burmese pythons.