Amazon river dolphins: 120 iconic pink dolphins found dead in Brazilian Amazon - as water temperatures soar

More than 100 of the Amazon's famous pink river dolphins - one of its most iconic species - have died in the past week, as the region grapples with severe drought.

The Mamiraua Institute, a research group from Brazil’s Ministry of Science, Technology and Innovation, told the Associated Press two more dead dolphins were found on Monday (2 October) around Tefe Lake, an ecological hotspot for freshwater life in the Brazilian Amazon.

Video provided by the institute showed vultures picking at dolphin carcasses washed up on the lakeside, while local media report thousands of fish have also died.

Experts are now warning that many more dolphins are also at risk of death, if the water in the region's lakes doesn't cool down soon. The Brazilian government last week sent teams of veterinarians and aquatic mammal experts to investigate the deaths.

Mamiraua Institute researcher Miriam Marmontel told AP there had been around 1,400 river dolphins in Tefe Lake. “In one week we have already lost around 120 animals... which could represent 5% to 10% of the population."

Ayan Fleischmann, the Institute's geospatial co-ordinator, said the drought had also had a major effect on the riverside communities in the Amazon region, with some more isolated communities unable to be reached due to rivers drying up.

“Many communities are becoming isolated, without access to good quality water, without access to the river, which is their main means of transportation,” he said. Water temperatures rose from 32C on Friday to almost 38C on Sunday.

Mr Fleischmann said they were still determining the cause of the dolphin deaths but the high temperature remained the main candidate.

Amazon river dolphins, also known locally as boto, are considered endangered by the International Union for Conservation of Nature (IUCN). The adults frequently become a striking pink in colour, and the species has been nicknamed the pink river dolphin.

With three distinct subspecies living across the wider Amazon rainforest, they are one of the world's last remaining freshwater dolphin species.