The Pantanal has the densest known population of jaguars anywhere on Earth, and here you see them in the open. It is the world's largest tropical wetland, a floodplain the size of a small country spread across western Brazil and into Bolivia and Paraguay. The basin is almost perfectly flat, dropping only centimetres over each kilometre, so the summer rains have nowhere to go. From November to March roughly 80 percent of it goes underwater and the savanna turns into a shallow inland sea. From June the water drains away and the animals crowd together around the shrinking rivers and lagoons. That is what makes this such good country for watching wildlife: instead of hiding in forest, everything gathers on banks you can see from a boat. The way in is the Transpantaneira, a raised dirt road running 147 kilometres south from Poconé to Porto Jofre on more than a hundred wooden bridges.
Along the Cuiabá and Três Irmãos rivers near Porto Jofre, seeing a wild jaguar is barely a matter of luck. These are among the largest jaguars alive, and in the dry months they laze on the banks in full daylight while boats drift close enough to hear them breathe. Yacaré caimans line the water by the thousand, lying with jaws open to cool. Giant otters fish in loud family groups, capybaras graze the edges, and cobalt hyacinth macaws cross overhead. Much of the wetland is protected, and its core was named a UNESCO World Heritage Site in 2000. Set out at first light, when mist still hangs over the water and the birds are waking. The day closes with the plains burning orange under a low sun and nothing on the horizon to cut it short. Come roughly July to October, when the animals are easiest to find and the road is passable.