Episode four of Wild Australia will be broadcast at 8:00PM on Monday 16th May on ITV1. In this episode Ray is in Australia’s tropical Rainforest, in the Wet Tropics, on the north-eastern coast of Australia. It’s the oldest on the planet, so old it stretches back to the time of the great supercontinents.

Ray starts his adventure by hitching a lift on a research crane, 47-metres above the ground, to get a bird’s eye view over the rainforest. From there he can see the geographical position responsible for this lush vegetation: the Great Dividing Range in the west, and the Pacific Ocean in the east.

As Ray heads back down to terra firma, the sun becomes a distant memory as he passes through layers and layers of leaves and branches – the forest’s canopy – a roof of vegetation which allows only a third of the sunlight to reach the ground.

Ray says: “This rainforest is so ancient that all life-forms have had millions of years to perfectly adapt to their habitat.”

One such species is the mind-boggling moth larvae, which has evolved to look like lichen, with even the way it moves appearing as if it’s being blown by the wind. There’s also the lichen spider, whose camouflage is so evolved that it snares its victims without the need for a web.

Pursuing his journey further into the rainforest, Ray travels through 400-metres of jungle on a zip-wire. Meanwhile, Ray’s cameraman Martin Hayward Smith has been filming an animal that can only be found in this part of the world: the elusive tree kangaroo, a marsupial which lives like a monkey and looks like a bear.

Finally, Ray gets on a quad bike for his last quest: a search for the notoriously elusive cassowary bird, a giant prehistoric flightless bird that lives deep in the rainforest, who, with its 12cm claws, is able to disembowel its enemies.

Ray’s expedition comes to a dramatic end when he encounters a cassowary with its chicks in tow.

Ray says: “What a magnificent thing to see. That really is the pinnacle of my visit to the rainforest. It’s an iconic bird, a vital, beautiful component of this forest. It’s from a time gone by. That has to be one of the very best things you could see in wild Australia.”