Even for wildlife lovers, Brazil’s Pantanal wetlands are overwhelming. Eagles and hawks sit on every other gate post and the blue sky is filled with the raucous calls of thousands of brightly coloured parrots. Giant anteaters, armour-plated armadillos and herds of white-tailed deer roam the grasslands taking shade under brilliantly coloured trumpet flower trees. Gullies, streams and rivers seem to overflow with crocodile-like caiman.

The wetlands are also the best place in the world for seeing that most elusive of all big cats, the jaguar - the New World's apex predator. Jaguars look a little like leopards. In pictures. In real life they are almost twice the size, with a bite more powerful than a Bengal tiger. They are also far, far harder to see. For decades jaguars have been harder to find than snow leopards, with film crews spending months on end in the wilds of South America with little more than a glimpse. Until now.

"We hear the jaguars letting out deep, throbbing calls like the bark of a giant dog."

One of our Brazilian friends, Ailton Lara, has been tracking jaguars since he was a boy. No one knows better where to find them. And now he works with a small team to share their majesty with us.

We are in the heart of the Pantanal. Metre-long indigo Hyacinth macaws nest nearby and ocelots and crab-eating foxes wander around at night. After waking at dawn to the trill of tanagers and the staccato call of the chacalaca – a turkey sized forest bird – we begin our journey with a sedate boat ride on the beautiful Cuiabá river.

There is wildlife everywhere. Capybara – which look like giant guinea pigs on stilts – burst from the river banks, huge jabiru storks flap lazily through the air and capuchin monkeys gaze inquisitively down from trees by the river bank.

"In the late afternoon we finally see our first. She's lazing under a fruit tree, a few metres from our boat."

After an hour or so the boat enters the heart of the Pantanal wilderness and the Cuiabá splits into smaller streams. There are no sounds but the babble of the river and the call of the birds and the air is so clean you can see for miles. Wildlife becomes even more exuberant and almost entirely fearless of humans. Two metre-long giant otters cavort around the boat like puppies. Herons stab at fish a few feet from the bow and kingfishers flit in and out of the trees.

Ailton searches the banks for jaguar. The cats rest here in the shade during the day, or enter the rivers and streams for a cooling swim. At dusk they hunt, ambushing capybara or hoiking caiman out of the water with a single paw. We hear the jaguars letting out deep, throbbing calls – like the bark of a giant dog.

We picnic on the river bank next to a cluster of giant cat footprints. And then in the late afternoon we see our first. She's lazing under the shade of a fruit tree, a few metres from our boat – so at ease she seems to be smiling from her deep green eyes. Revelling in her magnificence, we feel an adrenaline rush surge through our veins.

Tell Tale Tip: For a real chance of seeing jaguars in the wild, take our Jaguars & Waterfalls which is a private tour, just for you (minimum 2 travelling). Or our special departure small group tour, ideal for solo travellers and those who like to travel with others.