The Amazon is the biggest river in the world. Near Belem, its banks are home to the sloth. By Jack Barker
Belem, the busy port at the mouth of the Amazon in northern Brazil, is often left off tours. At the very tip of the road network, this is where transport gives up on muddy dirt roads and takes to the river. Indeed, the waterfront market is much the liveliest area of town. A constant stream of river traffic unloads sacks of produce and crates of evil-looking river fish. Hardware stalls selling nails and tools rub shoulders with vegetable stands, and clumsy pickpockets comb the alleys for the tourists who make it here.

It is largely for the tourists that the live sloths are produced. On first sight, they would seem ideal pets. Although anyone concerned about wildlife welfare would take a dim view of their presence here, these unambitious animals bring a broad smile to anyone who has ever felt the slightest need for affection. As soon as they get within reach of a person they wrap them in a slow, gentle, three-toed hug.

This is all due to a fairly basic misunderstanding. The poor deluded creatures think all upright supportive shapes are trees. But although the market salesman, aiming for his asking price of $8, might assure the tourist that the sloths can live on bananas, this is not the case. Sloths are fussy eaters and will die if they are offered only monkey- food.

They are not the hardest of animals to catch. They move through the Amazon jungle so slowly that they are apt to grow moss in the wet season. Dragging leaves laboriously to their mouths seems to exhaust them, and they even chew in a measured, meditative fashion.

In practice, this immobility serves them well as camouflage. The human hunter relies on finding animals by detecting movement, and great patience is needed to do this with a sloth. But the sloth is not an the sort of animal who can defend itself against a human predator. Even taking a mouthful of leaves seems to cause a minor crisis of conscience, and it is easy for a good climber to pluck the uncomplaining beast from its branch.

To stock up on baby parrots, the pet-shop stallholders simply send hunters out with saws. When a parrot is spotted nesting high in the jungle canopy, they cut down the tree. Any fledgelings that survive the crash have the exciting prospect of a lifetime sitting in a cage, probably learning Portuguese.

We were not here, however, to purchase sloths or parrots. As with anywhere in Brazil, the market is the cheapest place to eat. Rows of stalls are given over to restaurants running off gas cylinders: the cooks shout out to passers-by, advertising their food with desperation born of extreme poverty. Care is needed to make a choice based on food and not salesmanship. Avoid meals made from decaying meat, reheated into a blackish sludge, and search out the fresh choice steaks that are cooked and served for less than a dollar.

Like any Brazilian town, Belem has plenty of bars. These have more in common with the traditional bar toilet than the average cocktail bar, featuring large expanses of once-white tiles and shining sheets of stainless steel.

Belem is also much larger than it looks on the map and is home to more than a million people. As an internal river port, it has escaped much of the violent crime which makes the Atlantic gateways - like Recife - such exciting places to be in and such nice towns to leave. The beach culture that leads Brazil's tourist drive runs into dark silt at Belem, which can offer only a muddy Amazonian waterfront several miles out of town. Piranha paranoia keeps most Western tourists on solid ground, even though local children seem to swim and live.

Colonial historians will appreciate the way that the castle, built to discourage British tourists in our privateering days, has been preserved, restored, and even has a few lawns. This is unusual in the fertile, laid-back atmosphere of tropical Brazil. More characteristic are the downtown areas, which have an obscure charm based on decay tinged with corruption, rather than the areas tidily preserved for tourists. Grass grows in the upper floors of fine old buildings built by the Portuguese colonists, as chunks fall down on to the cobbled roads.

Most travellers visit Belem simply to start a trip up the Amazon. It is a shame not to stop here, as the town has a long history that characterises Brazil's boom-and-bust mentality. Initially a slaving port exporting Indians, the city's success threatened to leave it unpopulated. At one point, the Portuguese offered every white colonial who married an Indian girl a government dowry that included an axe, two pairs of scissors and a couple of cows. A rebellion in 1835 was followed by a blockade by the English and an invasion from inland, but Belem grew from its ashes with the rubber boom that funded reconstruction. Crumbling mansions and cathedrals testify to every stage of the city's long history, and opera fans will find the Teatro da Paz dripping with neo-classical features and rivalling the more famous theatre in Manaus.

If all that charm wears off, you can always buy a sloth.

The most economical way to get to Belem is to fly to Rio de Janeiro on a discounted ticket on Iberia, TAP Air Portugal or Viasa, and take a five-coupon airpass on the Brazilian carrier Vasp. You can take in several other cities for no extra cost; a possible routing is Rio-Salvador-Brasilia- Sao Paulo-Rio. Passage to South America (0171-602 9889) can put the trip together for about pounds 800, including tax but not a sloth.