Video Solves Mystery of How Narwhals Use Their Tusks

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A new study has shown narwhals , who live in the Arctic, can see with sound. (Credit: Dr. Kristin Laidre/NOAA)

(Click to enlarge) (Credit: Dr. Kristin Laidre/NOAA)

The unicorn of the sea just got a little less mysterious. Until now, how narwhals used their long tusks had been subject to much speculation by scientists. Behavior captured for the first time on camera shows narwhals using the long tusks protruding from their heads to stun Arctic cod by hitting them, using jagged, quick movements. This behavior immobilizes the fish, making them easier to prey upon.

(From National Geographic / by Sarah Gibbens) — The footage was shot by two drones in Tremblay Sound, Nunavat, in Canada’s far Northeastern regions by Adam Ravetch for the World Wildlife Fund Canada and researchers from Fisheries and Oceans Canada.

Brandon Laforest, a senior specialist of Arctic species and ecosystems with WWF-Canada, explained why narwhals have been such a mysterious species.

“They don’t jump like other whales. They are also notoriously skittish,” said Laforest. “This is an entirely new observation of how the tusk is used.”

Laforest, working with officials from the Canadian government, spent time camped in the narwhal’s winter habitat. Because of the remote regions in which narwhals live, visual confirmation of their behavior has been difficult to ascertain.

Marianne Marcoux, a research scientist for Fisheries and Oceans Canada, noted that drones have been an innovative tool for studying these elusive animals.

“Drones are very exciting, we can see things we couldn’t see before,” said Marcoux. Previous aerial observations were conducted by small planes that often provided an incomplete view or frightened the animals.

Three quarters of the world’s population can be found in neighboring Lancaster Sound, which is being considered by the Canadian government for a protected area.

While the footage confirms one theory of how narwhals use their tusks, they may be used for other purposes as well, such as for ice picks, weapons, sexual selection, or as a tool for echolocation. Laforest, however, thinks they may be especially important as sensory organs. Their tusks are covered in thousands of nerve endings and pores that help narwhals sense the environment around them.

“They can feel their surroundings similar to how a human’s broken tooth would have feeling,” said Marcoux.

The tusk is a left canine tooth protruding from the heads of males and can grow as long as nine feet. The right canine stays embedded, and no other teeth protrude from the inside of their mouths; narwhals instead use suction to swallow their prey whole.

The new footage is also significant for conservation efforts because it shows that narwhals feed in the waters in their summer waters. Scientists previously believed they fed exclusively in their winter waters around the southern portion of Baffin Island. Identifying the key regions that narwhals depend on for feeding and calving can help conservationists better preserve their environment and migratory routes.

Read the full story here: http://news.nationalgeographic.com/2017/05/drone-footage-narwhal-tusk-mystery/

 

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Recordings Reveal That Baby Humpback Whales ‘Whisper’ To Their Mothers

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A humpback whale and its calf in NOAA's Hawaiian Islands Humpback Whale National Marine Sanctuary. (Credit: NOAA)

(Click to enlarge) A humpback whale and its calf in NOAA’s Hawaiian Islands Humpback Whale National Marine Sanctuary. (Credit: NOAA)

Baby humpback whales seem to whisper to their mothers, according to scientists who have captured the infant whales’ quiet grunts and squeaks.

(From NPR / By Nell Greenfieldboyce) — The recordings, described in the journal Functional Ecology, are the first ever made with devices attached directly to the calves.

“When they’re born, these whales are around 5 meters long,” says Simone Videsen at Aarhus University in Denmark, who notes that this is “pretty big considering it’s a baby.”

Calves must travel with their mothers for thousands of miles during an annual migration to the food-rich waters of the Antarctic. Exactly what happens during that period is a mystery.

“These early life stages of wild whales are so elusive because they’re an aquatic animal,” Videsen explains. “We can’t follow them around all the time to see what they’re doing.”

However, she and some colleagues recently were able to track eight baby whales, using special sound and movement recorders. These recorders had suction cups that let the researchers just stick them onto the babies’ skin. “It can stay there for about a day and then it falls off,” Videsen says.

The researchers weren’t sure exactly what they’d hear when they retrieved the devices and played the audio. It turns out that the babbling of baby whales is very different than the haunting, eerie songs sung by adult male humpbacks.

Read the full story here: http://www.npr.org/sections/thetwo-way/2017/04/26/525609671/recordings-reveal-baby-humpback-whales-whisper-to-their-mothers

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A Genetic Oddity May Give Octopuses And Squids Their Smarts

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(Click to enlarge) Cirrate octopod, found at around 800m in the Gulf of Maine. View inside mantle. Stauroteuthis syrtensis is one of the few bioluminescent octopuses. Photophores in its mouth are believed to fool prey by directing them towards the mouth. It is relatively common off the continental slope of the eastern USA, although it occurs across the North Atlantic. This specimen was photographed during a 2004-2005 expedition to the Mid-Atlantic Ridge. ( Photo Credit: David Shale)

Coleoid cephalopods, a group encompassing octopuses, squid and cuttlefish, are the most intelligent invertebrates: Octopuses can open jars, squid communicate with their own Morse code and cuttlefish start learning to identify prey when they’re just embryos.

(From The New York Times / by Steph Yin) — In fact, coleoids are the only “animal lineage that has really achieved behavioral sophistication” other than vertebrates, said Joshua Rosenthal, a senior scientist at the Marine Biological Laboratory in Woods Hole, Mass. This sophistication could be related to a quirk in how their genes work, according to new research from Dr. Rosenthal and Eli Eisenberg, a biophysicist at Tel Aviv University.

In the journal Cell on Thursday, the scientists reported that octopuses, squid and cuttlefish make extensive use of RNA editing, a genetic process thought to have little functional significance in most other animals, to diversify proteins in their nervous system. And natural selection seems to have favored RNA editing in coleoids, even though it potentially slows the DNA-based evolution that typically helps organisms acquire beneficial adaptations over time.

Conventional wisdom says that RNA acts as a messenger, passing instructions from DNA to protein builders in a cell. But sometimes, enzymes swap out some letters — the ACGU you might have learned about in school — in the RNA’s code for others. When that happens, modified RNA can create proteins that weren’t originally encoded in the DNA, allowing an organism to add new riffs to its base genetic blueprint.

This RNA editing seemed to be happening more in coleoids, so Dr. Eisenberg, Dr. Rosenthal and Noa Liscovitch-Brauer, a postdoctoral scholar at Tel Aviv University, set out to quantify it by looking for disagreements in the DNA and RNA sequences of two octopus, one squid and one cuttlefish species.

They found that coleoids have tens of thousands of so-called recoding sites, where RNA editing results in a protein different from what was initially encoded by DNA. When they applied the same methods to two less sophisticated mollusks — a nautilus and a sea slug — they found that RNA editing levels were orders of magnitude lower.

Next, the researchers compared RNA recoding sites between the octopuses, squid and cuttlefish species and found that they shared tens of thousands of these sites to varying degrees. By comparison, humans and mice share only about 40 recoding sites, even though they are hundreds of millions of years closer in evolution than octopuses and squids.

“Evolutionarily, that’s a big deal,” said Jin Billy Li, an assistant professor of genetics at Stanford, who was not involved in this study. The findings suggest that the editing sites are very important, he added.

Read the full article here: https://www.nytimes.com/2017/04/06/science/octopus-squid-intelligence-rna-editing.html?_r=0

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Indonesia: Villagers resist eviction for 50 sq.km airport city on their land

Ten villages and surrounding farmland have already been wiped from the map for a 50 sq.km airport and surrounding ‘aeropolis’ or airport city in West Java, Indonesia, writes Rose Bridger. And while investors are offered an ‘attractive incentives plan’, villagers are subject to fierce state repression and brutality. Now only a single village remains standing, but residents continue to resist eviction and demand an end to the project.
Environment news & analysis, climate change reports –
The Ecologist

Manatees Just Lost Their Status as Endangered Species

Manatees have just been downlisted from endangered to threatened; and while some are celebrating their recovery, many advocates are fearing that the move puts their future survival in jeopardy.

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Species’ traits influenced their response to recent climate change

Modelling of mammal and bird responses to recent climatic changes—based on a systematic review of the literature—suggests that large numbers of threatened species have already been affected by climate change in at least part of their range.

Nature Climate Change doi: 10.1038/nclimate3223


Nature Climate Change – AOP – nature.com science feeds

New Discovery Indicates Early Whales Vacuumed Up Their Food

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Baleen, seen in the mouth of this whale, is used for feeding in some whale species. Scientists have discovered how feeding worked in ancient whales that are related to modern-day baleen whales. (Credit: Teddy Llovet/Flickr)

(Click to enlarge) Baleen, seen in the mouth of this whale, is used for feeding in some whale species. Scientists have discovered how feeding worked in ancient whales that are related to modern-day baleen whales. (Credit: Teddy Llovet/Flickr)

At 98 feet long and 200 tons, blue whales are by far the largest animals on Earth. To get that massive, blue whales need to eat millions of calories. A day. They feed exclusively through baleen filter feeding and can gulp down nearly 8,000 pounds of krill per day. Baleen, a substance used for feeding found only in whales, is made out of keratin–the same stuff as human hair and nails.

(From Forbes / by Shaena Montanari)– These ragged plates at the opening of the mouth allow whales to filter thousands of gallons of water to strain out literally tons of krill to eat. Baleen makes a relatively recent appearance in whale evolutionary history, and now it seems it may have appeared more recently than previously thought according to a new study by paleontologist Felix Marx of Museums Victoria and Monash University and an international team of colleagues in the journal Memoirs of Museum Victoria.

Although there are 15 living species of filter feeding baleen whales, earlier in their 50-million-year evolutionary history, whales just had teeth for chomping. Baleen does not fossilize easily, so paleontologists have been left wondering when and how exactly whales made the transition from teeth to baleen. A new 25 million-year-old fossilized whale skull from Washington may hold the answer.

The yet-unnamed species of extinct whale nicknamed “Alfred” is a member of a group called aetiocetids. Aetiocetids lived during the Oligocene (33-23 million years ago) and are early whales that had teeth for eating prey larger than krill, the preferred diet of modern baleen whales. It has typically been thought aetiocetids may have had both baleen and teeth, but this is difficult to prove without the presence of fossilized baleen.

The tooth wear patterns on the new fossil seem to tell a strange and unexpected story. Almost all of the tooth enamel on the back side of the tooth, the part that touches the tongue, has been scoured away. All of the teeth are worn in this very peculiar fashion. Marx and colleagues noted that it looks most like tooth wear seen in other marine mammals that feed by sucking water and food through their teeth rather than biting at it. Walruses are known to feed in this manner and often have similar looking horizontal striations on the enamel surfaces of their teeth.

Read the full article here: http://www.forbes.com/sites/shaenamontanari/2016/11/29/new-discovery-indicates-early-whales-vacuumed-up-their-food/#3d9ffcaf47de

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Porpoises Plan Their Dives And Can Set Their Heart Rate To Match

Ocean Leadership ~

Harbor porpoises have been found to be able to continually adjust their heart rate for diving. (Credit: Erik Christensen/Wikimedia Commons)

(Click to enlarge) Harbor porpoises have been found to be able to continually adjust their heart rate for diving. (Credit: Erik Christensen/Wikimedia Commons)

Two captive harbour porpoises called Freja and Sif have helped to reveal that porpoises —and probably all cetaceans — consciously adjust their heart rate to suit the length of a planned dive.

(From New Scientist / by Andy Coghlan)– By doing this, the animals optimise the rate at which they consume oxygen beforehand to match the intended depth and length of their dive.

“Until now, we knew that the heart rates of porpoises and cetaceans in general correlate with different dive factors, such as dive duration, depth and exercise,” says Siri Elmegaard of Aarhus University in Denmark, who led the research. “Now we can conclude that harbour porpoises have cognitive control of their heart rate.”

The discovery might also provide another explanation for how exposure to loud noise from shipping, sonar or subsea exploration harms cetaceans and possibly triggers strandings.

If their concentration is disrupted by sudden loud noise, it could prompt animals to panic and resurface too quickly, triggering potentially fatal decompression sickness, pain or confusion, and leading to possible stranding.

Researchers discovered as far back as 1975 that pinnipeds — such as sea lions — had the ability to consciously control their heart rate.

“What is remarkable is that it has taken four decades since the pioneering work on the cognitive control of heart rate in sea lions for researchers to ask the same question for cetaceans,” says Terrie Williams of the University of California, Santa Cruz. “This latest discovery is indeed an exciting advance in our understanding of the dive response in whales and dolphins.”

Read the full article here: https://www.newscientist.com/article/2113451-porpoises-plan-their-dives-and-can-set-their-heart-rate-to-match/

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Experts call on international climate change panel to better reflect ocean variability in their projections

A commentary on what should be included in the next IPCC special interdisciplinary report on oceans and the cryosphere has been released today in Nature by Daniela Schmidt, Professor of Palaeobiology from the University of Bristol and Philip Boyd, a professor of marine biogeochemistry from the Institute for Marine and Antarctic Studies, University of Tasmania.

The IPCC is an international body which was set up in 1988 to assess the science related to climate change.

Currently on its sixth assessment cycle, the goal of the IPCC is to inform policymakers of the science on climate change, the impacts, future risks and potential options for adaption and mitigation.

The latest IPCC report had for the first time chapters dedicated to the Oceans. This year, the IPCC are going one step further with a special interdisciplinary report on the ocean and the cryosphere which will be published in 2019.

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Mother Seals Are Transferring Dangerous Environmental Pollutants To Their Pups

Ocean Leadership ~

Scientists have found that hooded seal mothers pass on environmental pollutants to their pups through their milk. (Credit: NOAA Fisheries)

(Click to enlarge) Scientists have found that hooded seal mothers pass on environmental pollutants to their pups through their milk. (Credit: NOAA Fisheries)

Researchers have discovered that hooded seal mothers are inadvertently passing on environmental pollutants to their newborn offspring. The toxins are transferred through the placenta and the mother’s milk. The details are in a paper that was just published in the journal Environmental Toxicology and Chemistry.

(From Natural Science News / by Joanna Lawrence)– Perfluoroalkyl substances (PFASs) are common environmental contaminants that are only just now being properly studied. Many of these chemicals have been banned but some are still used in carpets, textiles, packaging, and other products. They persist in the environment and can be toxic to the native wildlife. PFASs and similar chemicals frequently end up in the systems of marine organisms. Predators such as marine mammals are especially at risk because they eat contaminated prey, resulting in a build-up of chemicals in their bodies.

Hooded seals (Cystophora cristata) are large marine mammals found throughout the Arctic region. Adult males have an odd inflatable bladder on the top of their head. The bladder is normally used during mating displays or territorial disputes. Females lack the head ornament and have silver fur with black spots. Hooded seal mothers nurse their young for a short 3 to 4 days. Since the pups feed exclusively on milk during this time, the species is a good model for studying the possibility of PFAS transfers to offspring.

The research team captured 15 lactating hooded seals and their pups. Blood and milk samples were taken and the animals were then released. The samples were analyzed in a laboratory at the Norwegian University of Life Sciences.

Read the full article here: http://naturalsciencenews.com/2016/10/24/mother-seals-are-transferring-dangerous-environmental-pollutants-to-their-pups/

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