The great plains of Brazil are one of South America's best kept secrets. Strange creatures walk in a sea of grass the outside world hardly knows. Theirs is a land of extremes dominated by the fiercest elements of nature. For half the year it's tinder dry and ravaged by fire. For the other six months it's drenched by torrential rain. And there's another side to this secret land. Huge torrents of water cascade off the grassland plain in a deluge so mighty it creates the greatest expanse of seasonal swamp on earth. This is a vast wetland that teems with wildlife. The huge swamps and the high grasslands are the two extraordinary faces of South America's Great Plains. The swamp is called the Pantanal a wetland the size of England and Wales combined. The grassy plateau surrounding it is the Cerrado. It's as big as the whole of Western Europe although 60% is now ranchland and farms. The last remnants of the Cerrado's grassland have their own unique animals. This may look like a fox on stilts but it's actually a maned wolf. The wolf is the largest predator on the open plains but what it hunts is tiny. Finding it is like looking for a needle in a haystack. Massive ears help it pinpoint its prey. And this is what it's after a little mouse. The wolf stamps on the ground to try and panic it into running.