From lost cities to eerie ‘ghost dogs' – six mysterious discoveries from deep inside the Amazon rainforest

The Sun

18-05-2025

The Amazon is one of the planet's last great wildernesses, stretching across nine countries in South America.
It has been a source of mystery and legends for centuries, and is home to poisonous creatures, lost cities and even a boiling river.
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Deadly creatures
The Amazon basin is home to a variety of poisonous creatures.
There are roughly over 100 species of poison dart frogs, at least 17 species of venomous snakes, and other dangerous animals like the Brazilian wandering spider, Amazonian giant centipede, and electric eel.
Earlier this week, wildlife researchers from Instituto Nacional de Pesquisas da Amazônia in Brazil announced they had discovered a new species of poisonous dart frog.
Discovered in still-isolated parts of the jungle, the Ranitomeya aetherea - a blue frog with copper legs and spots on its head - is just 15 mm long.
The small-but-deadly new creature is one of two Ranitomeya discovered over the past decade.
Lost cities
Earlier this year, a huge ancient city was uncovered in the Amazon, changing completely what researchers knew about the history of people living there.
Hidden for thousands of years by lush vegetation, the lost city hosted houses and plazas, connected by winding networks of roads and canals.
While researchers knew of mountainous or hillcrest cities, like Machu Picchu in Peru, it was believed that people only lived nomadically or in tiny settlements in the low-lying jungle.
Located in the Upano area in eastern Ecuador, it is now considered the oldest city in the Amazon.
"This is older than any other site we know in the Amazon," Professor Stephen Rostain, director of investigation at the National Centre for Scientific Research in France and research lead, said at the time.
"We have a Eurocentric view of civilisation, but this shows we have to change our idea about what is culture and civilisation."
Archeologists believe it was built around 2,500 years ago, and was inhabited for up to 1,000 years.
Exactly how many people lived there at any one time is hard to say - but it is certainly in the 10,000s, if not 100,000s.
Antoine Dorison, who co-authored a study with Rostain on the lost city, added: "It changes the way we see Amazonian cultures.
"Most people picture small groups, probably naked, living in huts and clearing land - this shows ancient people lived in complicated urban societies."
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'Ghost dogs'
Rumours of a short-eared dog sniffing around the Amazon had baffled scientists for years - so much so they have earned the nickname 'ghost dogs'.
These pups are so rare that even lifelong residents of the Amazon might never see one.
Although if you're lucky enough to catch one - it will be somewhere south of the Amazon River and east of the Andes Mountains.
Much of what is now known is thanks to Renata Leite Pitman, a biologist and veterinarian who actually owned one herself.
In 2009, Pitman heard of a short-eared dog puppy being sold to a logger at a market.
But the dog's buyer had second thoughts when it started eating the neighbours' chickens - and relinquished ownership to Pitman.
The pup, named Oso - meaning bear, would attract other short-eared dogs on walks through the rainforest with Pitman.
These walks allowed scientists to observe the animals interacting for the very first time.
Scientists learned that short-eared dogs eat meat and fish, as well as a variety of fruits, including Brazil nuts, forest açaí, breadnuts, and eggfruits.
'Ghost dogs', while rare, are believed to play an important role in spreading the seeds of many plants and trees.
River of boiling water
Shanay-Timpishka - also known as the river of boiling water - is not one you'd want to dip your toes in.
With temperatures of up to 98-110°C (208.4-230°F), the Shanay-Timpishka can cause severe burns in seconds.
The scalding waters, found in the Peruvian Amazon, are caused by geothermal activity.
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Monster snakes
The green anaconda rules the rainforest.
Often referred to as the "Queen of the Amazon", these snakes can reach up to 8.8m (29ft) in length.
But earlier this year, researchers discovered that examples of the famous green anaconda were actually two distinct species thought to have split almost 10million years ago.
Although they look identical, they are genetically very different, a 17-year-long study revealed.
The differences in their DNA is as much as five per cent.
For context, the difference between humans and our ape relatives is roughly two per cent.
Scientists have suggested defining the two by their localities - the northern green anaconda, scientifically known as Eunectes akayima, and the southern green anaconda, or Eunectes murinus.