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First Ever Tagging of Amazon Dolphins to Boost Conservation Efforts

Animals
First Ever Tagging of Amazon Dolphins to Boost Conservation Efforts
Freshwater dolphins being rounded up during tagging operation in Bolivia. Jaime Rojo / WWF-UK

For the first time ever, the World Wildlife Fund (WWF) and research partners are now tracking river dolphins in the Amazon using satellite technology after scientists successfully tagged dolphins in Brazil, Colombia and Bolivia, attaching small transmitters that will provide new insights into the animals' movements and behavior and the growing threats they face.


As of Dec. 5, 11 dolphins, including both Amazonian and Bolivian river dolphins—two of the four species of freshwater dolphin found in the world's largest river system—have safely been tagged and researchers are already studying the incoming data.

Despite their iconic status, little is known about the populations, habits or key habitats of river dolphins in the Amazon. While there are estimated to be tens of thousands of river dolphins, the species are currently listed as Data Deficient on the IUCN Red List of Threatened Species. The tags will enable WWF and its partners to study where the dolphins go, where they feed and how far they migrate.

Freshwater dolphin being cared for during first ever tagging process in the Amazon in Bolivia.Jaime Rojo / WWF-UK

"Satellite tracking will help us better understand the lives of this iconic Amazonian species more than ever before, helping to transform our approach to protecting them and the entire ecosystem," said Marcelo Oliveira, WWF Conservation Specialist, who led the expedition in Brazil. "Tagging these dolphins is the start of a new era for our work because we will finally be able to map where they go when they disappear from sight."

The tracking data will also guide efforts to tackle some of the major threats facing river dolphins, including hundreds of planned dams that would fragment many of the Amazon's remaining free flowing rivers, worsening mercury contamination from small-scale gold mining, and illegal fishing.

Amazon river dolphins in Bolivia.Jaime Rojo / WWF-UK

"We who live in the Amazon know that our environment is facing growing and unprecedented threats and that our future is linked to the future of dolphins," said Fernando Trujillo from Fundación Omacha, a Colombian research partner.

"This tagging project is critical because it will generate information that will enable governments across the region to target resources to protect dolphins and their habitats, which so many other species and communities also depend on," added Trujillo.

The capture and tagging of the dolphins followed a rigid protocol that prioritizes the welfare of the animals. Having been caught in nets by teams of specialists, the dolphins were taken to shore for tagging in an operation lasting 15 minutes on average, before being released back into the water. None of the dolphins were injured during the operation and none displayed any ill effects after release.

Along with installing the transmitters, the scientists also took samples from the animals, which they will analyze for mercury levels and general health.

WWF and its partners will assess this historic tagging operation over the coming months and will look to scale it up and tag more dolphins if the technology continues to prove successful. The initiative is the latest step in WWF's long-term efforts to conserve river dolphins across the Amazon.

In addition to scientific research, WWF will continue to work with communities, advocate with authorities and promote the creation of new protected areas.

A net-casting ogre-faced spider. CBG Photography Group, Centre for Biodiversity Genomics / CC BY-SA 3.0

Just in time for Halloween, scientists at Cornell University have published some frightening research, especially if you're an insect!

The ghoulishly named ogre-faced spider can "hear" with its legs and use that ability to catch insects flying behind it, the study published in Current Biology Thursday concluded.

"Spiders are sensitive to airborne sound," Cornell professor emeritus Dr. Charles Walcott, who was not involved with the study, told the Cornell Chronicle. "That's the big message really."

The net-casting, ogre-faced spider (Deinopis spinosa) has a unique hunting strategy, as study coauthor Cornell University postdoctoral researcher Jay Stafstrom explained in a video.

They hunt only at night using a special kind of web: an A-shaped frame made from non-sticky silk that supports a fuzzy rectangle that they hold with their front forelegs and use to trap prey.

They do this in two ways. In a maneuver called a "forward strike," they pounce down on prey moving beneath them on the ground. This is enabled by their large eyes — the biggest of any spider. These eyes give them 2,000 times the night vision that we have, Science explained.

But the spiders can also perform a move called the "backward strike," Stafstrom explained, in which they reach their legs behind them and catch insects flying through the air.

"So here comes a flying bug and somehow the spider gets information on the sound direction and its distance. The spiders time the 200-millisecond leap if the fly is within its capture zone – much like an over-the-shoulder catch. The spider gets its prey. They're accurate," coauthor Ronald Hoy, the D & D Joslovitz Merksamer Professor in the Department of Neurobiology and Behavior in the College of Arts and Sciences, told the Cornell Chronicle.

What the researchers wanted to understand was how the spiders could tell what was moving behind them when they have no ears.

It isn't a question of peripheral vision. In a 2016 study, the same team blindfolded the spiders and sent them out to hunt, Science explained. This prevented the spiders from making their forward strikes, but they were still able to catch prey using the backwards strike. The researchers thought the spiders were "hearing" their prey with the sensors on the tips of their legs. All spiders have these sensors, but scientists had previously thought they were only able to detect vibrations through surfaces, not sounds in the air.

To test how well the ogre-faced spiders could actually hear, the researchers conducted a two-part experiment.

First, they inserted electrodes into removed spider legs and into the brains of intact spiders. They put the spiders and the legs into a vibration-proof booth and played sounds from two meters (approximately 6.5 feet) away. The spiders and the legs responded to sounds from 100 hertz to 10,000 hertz.

Next, they played the five sounds that had triggered the biggest response to 25 spiders in the wild and 51 spiders in the lab. More than half the spiders did the "backward strike" move when they heard sounds that have a lower frequency similar to insect wing beats. When the higher frequency sounds were played, the spiders did not move. This suggests the higher frequencies may mimic the sounds of predators like birds.

University of Cincinnati spider behavioral ecologist George Uetz told Science that the results were a "surprise" that indicated science has much to learn about spiders as a whole. Because all spiders have these receptors on their legs, it is possible that all spiders can hear. This theory was first put forward by Walcott 60 years ago, but was dismissed at the time, according to the Cornell Chronicle. But studies of other spiders have turned up further evidence since. A 2016 study found that a kind of jumping spider can pick up sonic vibrations in the air.

"We don't know diddly about spiders," Uetz told Science. "They are much more complex than people ever thought they were."

Learning more provides scientists with an opportunity to study their sensory abilities in order to improve technology like bio-sensors, directional microphones and visual processing algorithms, Stafstrom told CNN.

Hoy agreed.

"The point is any understudied, underappreciated group has fascinating lives, even a yucky spider, and we can learn something from it," he told CNN.

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