In early October 2023, it was reported that more than 120 pink river dolphins had been found dead in Lake Tefé, which is connected to the Amazon River. Local scientists hypothesize that the deaths occurred because the region has experienced record heat and drought, which in turn places the blame on human-caused climate change. Yet in addition to reducing greenhouse gas emissions from fossil fuels and other sources, other direct efforts will be necessary to save pink river dolphins — and, for that matter, all six surviving species of river dolphins — from extinction.
“River dolphins are very social animals, and they love to play.”
Many nations are aware of these risks, and one proposal to address it is the Global Declaration for River Dolphins, which was signed earlier this month by 11 out of the 14 countries that are native to river dolphins.
“The Declaration has 8 elements, including concrete aspects on threat reduction (reduce unsustainable fisheries, work to solve water quantity and quality issues), increasing protection (more and connected protected areas, with effective management), invest in awareness raising, working closely with the local communities and fundraising,” Daphne Willems, WWF Lead River Dolphin Rivers initiative, told Salon by email.
Willems added that the different nations will need to collaborate effectively for the agreement to be effective, noting that “dolphins do not respect country borders.” She also stressed the importance of local cooperation, saying that “the local communities are the eyes and the ears of the river and the river dolphins, so they will need to play an active role in all of this, to make true change happen.”
Although the deaths of the 120 pink river dolphins underscored the need for this agreement, it is hardly the only major incident. According to Fernando Trujillo, a National Geographic Explorer and founder of the Omacha Foundation (which engages in Colombian conservation projects), the Amazon pink river dolphin population in the Mamirauá Sustainable Development Reserve declined by 65% between 1994 and 2016. While climate change is not the only factor in this depressing phenomenon, it is certainly a significant one.
“River dolphins across the Amazon face threats from deforestation, pollution of the rivers and wetlands where they live, loss of connectivity of bodies of water, hydropower dams, unsustainable fishing practices and habitat loss,” Trujillo said. “Threats to their habitat are becoming exacerbated by climate change which has intensified drought and access to water resources as well as livable conditions due to intense heat waves.”
Willems further elaborated on Trujillo’s point, describing how previously experts believed the three major threats to river dolphin populations were unsustainable fishing practices that led to entanglements and drownings, contamination like chemical and agricultural pollution and infrastructure development like the construction of dams. Yet climate change has added an entirely new variable into the mix of anthropogenic factors that hamper dolphins’ quality of life.
Want more health and science stories in your inbox? Subscribe to Salon’s weekly newsletter Lab Notes.
“When you rescue a river dolphin from a situation he cannot get out of himself (like when trapped in a pool that is disconnected from the main river), he cooperates with his rescuer, trying to help you to help him.”
“Climate change in itself does not need to be a problem per se; rivers and river species are used to dynamic situations and can adapt,” Willems explained. “Natural, healthy river systems are resilient, and so are the species living there. But the systems cannot adapt when they have been altered too much. River dolphins can live in water until 38° Celsius [100.4º Farenheit]. But what we saw last month in the Brazilian Amazon, where Tefe lake was heated until 41° Celsius [105.8º Farenheit], is beyond their adaptation potential.”
Willems added, “Climate change worsens all the mentioned negative effects from human interventions.”
If river dolphins are ultimately lost to the world due to climate change and other human-driven factors, Earth will lose one of its most intelligent and unique species. Willems, for example, shared a story about how she observed a male river dolphin put on a sophisticated dance for the entertainment of a female river dolphin.
“River dolphins are very social animals, and they love to play. I once witnessed a dolphin that tried to impress a female dolphin; an impressive smashing of water, almost dancing,” Willems described. “They go as far as using ‘instruments’: tree branches functioning like sticks. We have footage of two dolphins playing together with one anaconda – they clearly enjoy themselves (as you can see by the very pink skin at that moment, showing their excitement).”
Willems also described how river dolphins show intelligence when trying to extricate themselves from situations that less intelligent animals might find overwhelming.
“When you capture a dolphin to get it a satellite tag in its dorsal fin (to follow migrations movements, to learn and be able to better protect the species), he understandably resists,” Willems told Salon. “But when you rescue a river dolphin from a situation he cannot get out of himself (like when trapped in a pool that is disconnected from the main river), he cooperates with his rescuer, trying to help you to help him.”
The dolphin expert stressed that river dolphins are so intelligent, they actually have easily distinguishable personalities.
“Dolphins are individual characters; some stay around at the same place all their life, with daily routines,” Willems explained. “They recognize the boats that pass, some local community people told us they recognize individual people. Other dolphins migrate and explore, travel until 100s of kilometers.”
They also communicate with each other using complex combinations of echolocation clicks that “gives them a super-power,” Willems said, because “these click sounds are very directional – so a river dolphin next to me could be telling you some tale without the dolphin behind me having a clue. Just three years ago, we saw for the first time the extraordinary vocal repertoire of the Boto, the Amazon River dolphin – they are using up to 2000 ultrasonic clicks per second in complex patterns that clearly represent many distinct ‘words.'”
Trujillo even shared a story of a river dolphin showing respect for a valuable piece of his property.
“A vivid memory I have is a beautiful experience when National Geographic Society sent a photographer with me to document swimming in a lagoon with the river dolphins,” Trujillo recalled. “As I was descending into the water I lost my head scarf, I thought, oh my God, now it’s gone! But after two minutes, I felt something on my arm. It was the flipper of a dolphin with the head scarf laid on top of it. It was incredible. Everybody on the boat was in shock.”
Read more
about dolphins and whales
