Scientist at Work: Identifying Individual Gray Wolves by Their Howls
By Angela Dassow
Love them or hate them, wolves are vital members of natural ecosystems and the health of a wolf population can be an important factor in maintaining balance among species. Wolf populations are growing in North America—the Great Lakes region in particular now supports more than 3,700 individuals. Keeping track of wolf pack movements is important for reducing human-wolf conflicts which can arise when packs move too close to ranches.
The traditional way to track wolves involves setting traps, sedating and then radio-collaring individual animals. While effective, this approach is time intensive and expensive, and entails risks for the animals.
I was fortunate to participate in this entire process firsthand as an undergraduate student. During the summer trapping seasons, I became familiar with each of the wolves in the central forest region of Wisconsin. This experience led to several conversations with the wildlife biologists in the area about whether wolf howls could be used to help identifying non-radio-collared pack members.
This question remained a fun thought experiment for many years. Now as a biology professor who specializes in bioacoustics, I've been able to turn that thought experiment into a full research question: Can we use acoustic features to identify individual wolves in the wild?
Downsides of Radio Collaring
Because of the many challenges involved in radio collaring an animal, it would be useful to have a new way to identify and track wild wolves.
To successfully set a trap, wildlife managers must first spend days, if not weeks, scouting for signs of wolves. Once they've identified a suitable area, they set traps that must be checked every 24 hours. If successful, the animal needs to be sedated before it can be removed from the trap—which can be stressful both for the wolf and the researchers involved.
A sedated wolf cannot regulate its body temperature and overheating can become an issue on hot days. Human handling of a sedated wolf can also be stressful on the pack members that are often nearby, observing the scene. Even after an animal is successfully radio-collared and released, it's still vulnerable to predators while the sedative wears off.
In spite of these risks, radio-collaring has been the standard way to track populations because each collar's radio-transmitter frequency acts as a unique identifier of an individual. Researchers can then use aerial surveys where a pilot searches for the collared animal or ground surveys where a field crew drives throughout a pack territory searching for feedback from the radio signal. This method is used to track a wide array of animals, including turtles, birds, bats, whales, fish, snakes and more.
Angela Dassow and Cara Hull survey a road in central Wisconsin for signs of wolves. Caitlin McCombe / CC BY-ND
Listening to Learn Who's Who
In 2013, behavioral ecologist Holly Root-Gutteridge and her colleagues successfully demonstrated that they could identify individual wolves in captivity using acoustic features. Their research provided evidence that it made sense to test whether vocal identification in wild animals is possible.
So with the support of the Summer Undergraduate Research Experience at Carthage College, volunteers from the Timber Wolf Information Network, and wildlife managers at Sandhill Wildlife Area in Babcock, Wisconsin, my undergraduate students Cara Hull and Caitlin McCombe and I began to record wolves in the wild.
It would be an understatement to say fieldwork can be challenging. On any given day, there can be daunting weather fluctuations. Biting insects, especially mosquitoes and deer flies, are abundant in wolf habitat. We had to constantly check ourselves for ticks. And then of course comes the actual fieldwork.
Wolves naturally avoid coming near people, but the best quality recordings are made up close to where the animals are producing the sounds. To get close with our audio equipment, we had to track the wolves every day to learn where they'd most recently been within their large territories. That's how we'd establish a starting point for our nightly recording sessions.
Fresh track from an adult gray wolf. Angela Dassow / CC BY-ND
Conducting a daily survey of wolf habitat requires driving or walking down every possible path within a wolf's territory. Signs of activity could include fresh footprints or tracks. This can tell us how many animals were in the area and what direction they were heading.
Large dogs can produce footprints that are similar in size to those of wolves; but the pattern of tracks can be distinguished based on the placement of their feet and the directness of the chosen route. Dogs have a tendency to wander more, while wolves will walk in a more efficient straight line.
In addition to tracks, we conduct a survey of fresh scat. It's not glamorous, but examining their feces provides valuable information about what the wolves have been eating and how recently they walked along a trail.
Carthage College biology students Cara Hull and Caitlin McCombe conduct a howl survey in central Wisconsin. Angela Dassow / CC BY-ND
Using the information from our daytime survey, we plan a shorter nighttime howling route. Howling is a natural behavior during the evenings, when wolves call to signal that a territory is occupied. At each stopping point on our route, a researcher must get out of the vehicle and howl while another researcher records with a microphone any wolf responses, announcing their presence or defending territory. If we are successful in eliciting a response, we continue in its direction until we get as close as possible.
Use of lights is discouraged since it can deter the wolves from calling again, so we needed to feel our way through the forest at night. Personally, I think it is incredibly exciting to be walking down a trail in the dark and have a wolf walk within feet of where I am. It may sound scary, but we are not in any danger since wolves prefer to avoid contact with humans. During our month-long survey, we were fortunate to experience two close wolf encounters.
Back in the Lab, Analyzing the Calls
With the howls recorded, we can return to the lab to analyze our findings using audio software.
Acoustic properties are measured using Adobe Audition. Angela Dassow / CC BY-ND
We were able to isolate 21 howls from two adult wolves over two evenings. For each howl, we made six types of frequency measurements and two types of duration measurements. Frequency is how high or low the pitch of the howl sounds and duration is the length of time the howl lasted.
For wild gray wolves, we found that the maximum frequency—that is, the highest sound an animal produced—and the frequency at the end of the howl were the two variables that were most individualistic. For captive wolves, it was different. The lowest frequency an individual produced—what in acoustics is called their fundamental frequency—and the loudness of its calls were the factors that best differentiated among the captive individuals.
The differences in useful identification information between wild and captive howls are likely a reflection of signal quality. The captive recordings are much clearer than what we were able to record in the wild, where we were typically at least half a mile away from the wolves; the signal degrades with distance. As signal quality declines, maximum frequency and end frequency become more useful in individual identification.
Based on our findings and previous research, it is possible to monitor gray wolf populations using non-invasive methods. To do so effectively, researchers would need to record known individuals in a particular area. Once they've built up a database of known individuals' howls, they can conduct nightly surveys. Comparing new recordings to those in the audio library would let them determine which individuals are in an area.
While radio-collaring procedures may still be useful in some cases, vocal identification is a promising alternative for monitoring individuals. Acoustic surveys are still a time-consuming process, but they eliminate the time needed to trap individuals and remove any possibility of accidentally injuring an animal in a trap. Additionally, once researchers gather a database of positively identified individuals, they can use remote monitoring stations to record howls, thus reducing the amount of time spent conducting nightly surveys. Acoustic monitoring could potentially track all the wolves in multiple packs whereas radio-collaring is typically used to track a single member in select packs.
Reposted with permission from our media associate The Conversation.
EcoWatch Daily Newsletter
By Tim Radford
German scientists now know why so many fish are so vulnerable to ever-warming oceans. Global heating imposes a harsh cost at the most critical time of all: the moment of spawning.
Nearing the Brink<p>Since <a href="https://climatenewsnetwork.net/abundant-fish-need-cool-seas-and-protection/" target="_blank">fish in the temperate zones already experience a wide variation</a> in seasonal water temperatures, it hasn't been obvious why species such as <a href="https://climatenewsnetwork.net/sardines-swim-into-northern-waters-to-keep-cool/" target="_blank">cod have shifted nearer the Arctic, and sardines have migrated to the North Sea</a>.</p><p>But <a href="https://climatenewsnetwork.net/ocean-warming-spurs-marine-life-to-rapid-migration/" target="_blank">marine creatures are on the move</a>, and although there are other factors at work, including overfishing and <a href="https://climatenewsnetwork.net/fish-cant-smell-well-in-more-acidic-seas/" target="_blank">the increasingly alarming changes in ocean chemistry</a>, thanks to ever-higher levels of dissolved carbon dioxide, temperature change is part of the problem.</p><p>The latest answer, Dr Dahlke and his colleagues report in the journal <a href="https://science.sciencemag.org/cgi/doi/10.1126/science.aaz3658" target="_blank">Science</a>, is that many fish may already be living near the limits of their thermal tolerance.</p><p>The temperature safety margins during the moments of spawning and embryo might be very precise, and over hundreds of thousands of years of evolution, marine and freshwater species have worked out just what is best for the next generation. Rapid global warming upsets this equilibrium.</p>
By Sherry H-Y. Chou, Aarti Sarwal and Neha S. Dangayach
The patient in the case report (let's call him Tom) was 54 and in good health. For two days in May, he felt unwell and was too weak to get out of bed. When his family finally brought him to the hospital, doctors found that he had a fever and signs of a severe infection, or sepsis. He tested positive for SARS-CoV-2, the virus that causes COVID-19 infection. In addition to symptoms of COVID-19, he was also too weak to move his legs.
When a neurologist examined him, Tom was diagnosed with Guillain-Barre Syndrome, an autoimmune disease that causes abnormal sensation and weakness due to delays in sending signals through the nerves. Usually reversible, in severe cases it can cause prolonged paralysis involving breathing muscles, require ventilator support and sometimes leave permanent neurological deficits. Early recognition by expert neurologists is key to proper treatment.
We are neurologists specializing in intensive care and leading studies related to neurological complications from COVID-19. Given the occurrence of Guillain-Barre Syndrome in prior pandemics with other corona viruses like SARS and MERS, we are investigating a possible link between Guillain-Barre Syndrome and COVID-19 and tracking published reports to see if there is any link between Guillain-Barre Syndrome and COVID-19.
Some patients may not seek timely medical care for neurological symptoms like prolonged headache, vision loss and new muscle weakness due to fear of getting exposed to virus in the emergency setting. People need to know that medical facilities have taken full precautions to protect patients. Seeking timely medical evaluation for neurological symptoms can help treat many of these diseases.
What Is Guillain-Barre Syndrome?
Guillain-Barre syndrome occurs when the body's own immune system attacks and injures the nerves outside of the spinal cord or brain – the peripheral nervous system. Most commonly, the injury involves the protective sheath, or myelin, that wraps nerves and is essential to nerve function.
Without the myelin sheath, signals that go through a nerve are slowed or lost, which causes the nerve to malfunction.
To diagnose Guillain-Barre Syndrome, neurologists perform a detailed neurological exam. Due to the nerve injury, patients often may have loss of reflexes on examination. Doctors often need to perform a lumbar puncture, otherwise known as spinal tap, to sample spinal fluid and look for signs of inflammation and abnormal antibodies.
Studies have shown that giving patients an infusion of antibodies derived from donated blood or plasma exchange – a process that cleans patients' blood of harmful antibodies - can speed up recovery. A very small subset of patients may need these therapies long-term.
The majority of Guillain-Barre Syndrome patients improve within a few weeks and eventually can make a full recovery. However, some patients with Guillain-Barre Syndrome have lingering symptoms including weakness and abnormal sensations in arms and/or legs; rarely patients may be bedridden or disabled long-term.
Guillain-Barre Syndrome and Pandemics
As the COVID-19 pandemic sweeps across the globe, many neurologic specialists have been on the lookout for potentially serious nervous system complications such as Guillain-Barre Syndrome.
Though Guillain-Barre Syndrome is rare, it is well known to emerge following bacterial infections, such as Campylobacter jejuni, a common cause of food poisoning, and a multitude of viral infections including the flu virus, Zika virus and other coronaviruses.
Studies showed an increase in Guillain-Barre Syndrome cases following the 2009 H1N1 flu pandemic, suggesting a possible connection. The presumed cause for this link is that the body's own immune response to fight the infection turns on itself and attacks the peripheral nerves. This is called an "autoimmune" condition. When a pandemic affects as many people as our current COVID-19 crisis, even a rare complication can become a significant public health problem. That is especially true for one that causes neurological dysfunction where the recovery takes a long time and may be incomplete.
Though there is clear clinical suspicion that COVID-19 can lead to Guillain-Barre Syndrome, many important questions remain. What are the chances that someone gets Guillain-Barre Syndrome during or following a COVID-19 infection? Does Guillain-Barre Syndrome happen more often in those who have been infected with COVID-19 compared to other types of infections, such as the flu?
The only way to get answers is through a prospective study where doctors perform systematic surveillance and collect data on a large group of patients. There are ongoing large research consortia hard at work to figure out answers to these questions.
Understanding the Association Between COVID-19 and Guillain-Barre Syndrome
While large research studies are underway, overall it appears that Guillain-Barre Syndrome is a rare but serious phenomenon possibly linked to COVID-19. Given that more than 10.7 million cases have been reported for COVID-19, there have been 10 reported cases of COVID-19 patients with Guillain-Barre Syndrome so far – only two reported cases in the U.S., five in Italy, two cases in Iran and one from Wuhan, China.
It is certainly possible that there are other cases that have not been reported. The Global Consortium Study of Neurological Dysfunctions in COVID-19 is actively underway to find out how often neurological problems like Guillain-Barre Syndrome is seen in hospitalized COVID-19 patients. Also, just because Guillain-Barre Syndrome occurs in a patient diagnosed with COVID-19, that does not imply that it was caused by the virus; this still may be a coincident occurrence. More research is needed to understand how the two events are related.
Due to the pandemic and infection-containment considerations, diagnostic tests, such as a nerve conduction study that used to be routine for patients with suspected Guillain-Barre Syndrome, are more difficult to do. In both U.S. cases, the initial diagnosis and treatment were all based on clinical examination by a neurological experts rather than any tests. Both patients survived but with significant residual weakness at the time these case reports came out, but that is not uncommon for Guillain-Barre Syndrome patients. The road to recovery may sometimes be long, but many patients can make a full recovery with time.
Though the reported cases of Guillain-Barre Syndrome so far all have severe symptoms, this is not uncommon in a pandemic situation where the less sick patients may stay home and not present for medical care for fear of being exposed to the virus. This, plus the limited COVID-19 testing capability across the U.S., may skew our current detection of Guillain-Barre Syndrome cases toward the sicker patients who have to go to a hospital. In general, the majority of Guillain-Barre Syndrome patients do recover, given enough time. We do not yet know whether this is true for COVID-19-related cases at this stage of the pandemic. We and colleagues around the world are working around the clock to find answers to these critical questions.
Sherry H-Y. Chou is an Associate Professor of Critical Care Medicine, Neurology, and Neurosurgery, University of Pittsburgh.
Aarti Sarwal is an Associate Professor, Neurology, Wake Forest University.
Neha S. Dangayach is an Assistant Professor of Neurology and Neurosurgery, Icahn School of Medicine at Mount Sinai.
Disclosure statement: Sherry H-Y. Chou receives funding from The University of Pittsburgh Clinical Translational Science Institute (CTSI), the National Institute of Health, and the University of Pittsburgh School of Medicine Dean's Faculty Advancement Award. Sherry H-Y. Chou is a member of Board of Directors for the Neurocritical Care Society. Neha S. Dangayach receives funding from the Bee Foundation, the Friedman Brain Institute, the Neurocritical Care Society, InCHIP-UConn Center for mHealth and Social Media Seed Grant. She is faculty for emcrit.org and for AiSinai. Aarti Sarwal does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Reposted with permission from The Conversation.
One of the initial reasons social distancing guidelines were put in place was to allow the healthcare system to adapt to a surge in patients since there was a critical shortage of beds, ventilators and personal protective equipment. In fact, masks that were designed for single-use were reused for an entire week in some hospitals.
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By Jake Johnson
Unity Task Forces formed by presumptive Democratic presidential nominee Joe Biden and Sen. Bernie Sanders unveiled sweeping party platform recommendations Wednesday that—while falling short of progressive ambitions in a number of areas, from climate to healthcare—were applauded as important steps toward a bold and just policy agenda that matches the severity of the moment.
"We've moved the needle a lot, especially on environmental justice and upping Biden's ambition," said Sunrise Movement co-founder and executive director Varshini Prakash, a member of the Biden-Sanders Climate Task Force. "But there's still more work to do to push Democrats to act at the scale of the climate crisis."
The climate panel—co-chaired by Rep. Alexandria Ocasio-Cortez (D-N.Y.) and former Secretary of State John Kerry—recommended that the Democratic Party commit to "eliminating carbon pollution from power plants by 2035," massively expanding investments in clean energy sources, and "achieving net-zero greenhouse gas emissions for all new buildings by 2030."
In a series of tweets Wednesday night, Ocasio-Cortez—the lead sponsor of the House Green New Deal resolution—noted that the Climate Task Force "shaved 15 years off Biden's previous target for 100% clean energy."
"Of course, like in any collaborative effort, there are areas of negotiation and compromise," said the New York Democrat. "But I do believe that the Climate Task Force effort meaningfully and substantively improved Biden's positions."
Today the 6 Biden-Sanders Unity Task Forces are unveiling final language. The Climate Task Force accomplished a gr… https://t.co/gz3broq2qe— Alexandria Ocasio-Cortez (@Alexandria Ocasio-Cortez)1594240617.0
The 110 pages of policy recommendations from the six eight-person Unity Task Forces on education, the economy, criminal justice, immigration, climate change, and healthcare are aimed at shaping negotiations over the 2020 Democratic platform at the party's convention next month.
Sanders said that while the "end result isn't what I or my supporters would've written alone, the task forces have created a good policy blueprint that will move this country in a much-needed progressive direction and substantially improve the lives of working families throughout our country."
"I look forward to working with Vice President Biden to help him win this campaign," the Vermont senator added, "and to move this country forward toward economic, racial, social, and environmental justice."
Biden, for his part, applauded the task forces "for helping build a bold, transformative platform for our party and for our country."
"I am deeply grateful to Bernie Sanders for working with us to unite our party and deliver real, lasting change for generations to come," said the former vice president.
On the life-or-death matter of reforming America's dysfunctional private health insurance system—a subject on which Sanders and Biden clashed repeatedly throughout the Democratic primary process—the Unity Task Force affirmed healthcare as "a right" but did not embrace Medicare for All, the signature policy plank of the Vermont senator's presidential bid.
Instead, the panel recommended building on the Affordable Care Act by establishing a public option, investing in community health centers, and lowering prescription drug costs by allowing the federal government to negotiate prices. The task force also endorsed making all Covid-19 testing, treatments, and potential vaccines free and expanding Medicaid for the duration of the pandemic.
"It has always been a crisis that tens of millions of Americans have no or inadequate health insurance—but in a pandemic, it's potentially catastrophic for public health," the task force wrote.
Dr. Abdul El-Sayed, a former Michigan gubernatorial candidate and Sanders-appointed member of the Healthcare Task Force, said that despite major disagreements, the panel "came to recommendations that will yield one of the most progressive Democratic campaign platforms in history—though we have further yet to go."
We rein in #pharma's greed by: 1) Allowing Medicare to FINALLY negotiate Rx drugs FOR ALL AMERICANS 2) Using Rx d… https://t.co/6k9iUCLMp7— Abdul El-Sayed (@Abdul El-Sayed)1594238411.0
Observers and advocacy groups also applauded the Unity Task Forces for recommending the creation of a postal banking system, endorsing a ban on for-profit charter schools, ending the use of private prisons, and imposing a 100-day moratorium on deportations "while conducting a full-scale study on current practices to develop recommendations for transforming enforcement policies and practices at ICE and CBP."
Marisa Franco, director of immigrant rights group Mijente, said in a statement that "going into these task force negotiations, we knew we were going to have to push Biden past his comfort zone, both to reconcile with past offenses and to carve a new path forward."
"That is exactly what we did, unapologetically," said Franco, a member of the Immigration Task Force. "For years, Mijente, along with the broader immigrant rights movement, has fought to reshape the narrative around immigration towards racial justice and to focus these very demands. We expect Biden and the Democratic Party to implement them in their entirety."
"There is no going back," Franco added. "Not an inch, not a step. We must only move forward from here."
Reposted with permission from Common Dreams.
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