There have been reports since the 1800’s of living dinosaurs in Bolivia and other South American countries. At the end of the 19th century Scientific American recorded the following remarkable events: "The Brazilian Minister at La Paz, Bolivia, had remitted to the Minister of Foreign Affairs in Rio photographs of drawings of an extraordinary saurian killed on the Beni after receiving thirty-six balls. By order of the President of Bolivia the dried body, which had been preserved in Asuncion, was sent to La Paz." The "monster" was reported to be twelve meters long (39 ft) from snout to point of the tail, which latter was flattened. It’s head resemblance the head of a dog and its legs were short, ending with formidable claws. The legs and abdomen sported a kind of scale armour, and all the back is protected by a still thicker and double cuirass, starting from behind the ears of the anterior head, and continuing to the tail. The neck is long, and the belly large and almost dragging on the ground."( "A Bolivian Saurian," Scientific American, 49:3, 1883.)
It sounds like a crocodile like species but reports continued to trickle in. Franz Hermann Schmidt, a German traveller told of an encounter in 1907. Schmidt was travelling along the Solimoes River in Colombia along with Captain Rudolph Pfleng. Pfleng and Schmidt encountered some huge tracks along the shores of a small lake and trees nearby were stripped to a height of 14 feet. The following day, Schmidt, Pfleng and their Indian guides saw a dark shape among the trees on the shore. A large tapir-like head was suspended on a snakelike neck more than 10 feet above the ground. The creature advanced towards the party but did not seem agitated. It was some 8 or 9 feet tall, with clawed flippers in place of legs. The explorers opened fire on the beast and it dove back into the water. Sounds Like a strange sight, almost giraffe like head and neck .
In 1931, Harald Westin reported seeing a creature along Brazil's Rio Marmore . He said it was 20-foot long and resembled a legged boa constrictor. Leonard Clark reported that he heard tales when travelling up the Rio Perene in Brazil and was told of herbivorous creatures which sounded much like a prehistoric sauropod. . "In 1907 Lieutenant-Colonel Percy Fawcett of the British Army was sent to mark the boundaries between Brazil and Peru. He was an officer in the Royal Engineers and was well known as a meticulous recorder of facts. In the Beni Swamps of Madre de Dios Colonel P. H. Fawcett saw an animal he believed to be Diplodocus... The Diplodocus story is confirmed by many of the tribes east of the Ucayali..." (The Rivers Ran East by Leonard Clark, 1953.)
Then in 1975, a Swiss businessman was told by a guide called Simon Bastos, about such a dinosaur like creature. The long-necked creature had destroyed Bastos' canoe after he had landed along a riverbank. Bastos was later told that such long-necked creatures frequented deep waterholes, and rarely came out on land.
All hearsay and inconclusive and the report in Scientific America was later thought to be a hoax. The reports taken at face value seem to describe different creatures, creatures that we may recognise now but were not known then.
Then there are tales of giant apes ,like King Kong. The evidence amounts to mainly to a grainy photo published in a 1929 London newspaper. Sitting on a packing case, propped up with a large stick, was what purported to be the body of a giant ape, the “Mono Rey.” It was said to have inhabited the dense jungles of northern Bolivia, around the Madidi river.The last person to explore the region, Major Percy Harrison Fawcett , in the 1920s, disappeared without a trace. Simon Chapman, along with two companions, took a canoe into the swamps and rainforests of Bolivia to find the mythical monster of the Madidi. The story became a book: The Monster of the Madidi - Searching for the Giant Ape of the Bolivian Jungle. Simon Chapman.
He, however, did not find anything, but an interesting tale if you get chance to read it.
So the stories continue ,but I think the sightings may turn out to be creatures we now know and have named.I just love the romance of these tales though, the explorer hacking their way through the jungle , and coming across new wonders and unknown creatures.