On the island of Sri Lanka, leopards (Panthera pardus) are the reigning top predator and, with no other big cat to compete with, they have become super-sized – the biggest leopards in the world.

Elsewhere they are elusive predators, but here they have little to fear and can be seen proudly sauntering along the roads of Yala, the country’s most famous national park.

Boasting the highest density of leopards anywhere in the world, Yala is also home to the biggest of them all. Weighing in at almost 100kg, Ivan the one-eyed leopard enjoys a notoriety in these parts.

I joined producer Nick Lyon and cameraman Paul Stewart to film these formidable predators for the BBC Two series Wonders of the Monsoon.

Nocturnal predator

Using a specially adapted vehicle with infrared technology, and wearing night vision goggles, we ventured into the park at night. Leopards prefer to hunt under the cover of darkness, using their incredible hearing and night vision that is seven times more powerful than a human’s.

It wasn’t long before we detected the heat signature of a large male as it appeared from behind a bush. I was startled by how big it was. I’ve filmed leopards elsewhere in the world, but this cat looked more like a jaguar – a more muscular, powerful animal with larger jaws.

We were quietly filming more than 50 metres away, but the leopard turned and looked straight in our direction. He slowly started to approach.

We were in an open-backed vehicle so we could get a clear view of the action. Little did we know at the time, but the tiny monitors that we were using to film leaked enough light to catch the leopard’s attention.

He could clearly see us and it wasn’t long before he was well within leaping distance, less than five metres away. We couldn’t see him in the darkness, but we knew how close he was when Nick started to point the infrared camera down.

Quick reactions

Luckily we had an umbrella to hand. Nick flashed it open to startle the leopard, which retreated into the shadows.

It was an intimidating introduction to the leopards of Yala, but I don’t think we were ever in serious danger. The leopard was probably surprised to see humans in the park at night, especially when they were brightly illuminated, and simply decided to take a closer look.

But we certainly took a lesson from the encounter, and the next day we provided more protection around the sides of the vehicle.

The crew’s close encounter will be shown at the end of episode four: The Drought, Wonders of The Monsoon.

Watch Wonders of the Monsoon on Sunday at 20:00hrs on BBC Two, or catch up on BBC iPlayer.