3257. Praise Song for the Unloved Animals

By Margaret Renkl, The New York Times, May 27, 2019

The North American Opossum ( Didelphis virginiana)

NASHVILLE — Sing, O muse, of the lumbering opossum, of the nearsighted, stumbling opossum, whose only defenses are a hiss, a hideous scowl and a rank scent emitted in terror. Let us rejoice in the pink-nosed, pink-fingered opossum, her silvery pouch full of babies, each no bigger than a honeybee.

May your young thrive to ride upon your back. May they fatten and grow large and stumble off on their own to devour cockroaches and carrion and venomous snakes. May their snuffling root out all the ticks in our yards and all the snails in our flower beds. When they faint in the face of marauding dogs, we call back our baying hounds and wait for them to wake. We cheer when they rise and shake themselves. We send them with our blessings as they blunder back into the night.

Let peals of gratitude ring out for the glossy vulture, soarer of air currents, eater of gore. We gaze in wonder at your distant perfection, mistaking you for creatures we thoughtlessly love much more: for eagles or hawks or ospreys. Stolid in our heavy human bones, we follow you with our eyes, watching as you barely shift the angle of your wings to bank and glide, to circle and circle again.

May we remember in your circling the cycle you complete. On the ground, something is suffering. Something is coming near to the end of its time among us, but its life is not ending. Its life can never end. You are turning its body into something beautiful: blood and feathers and hollow bones. Earthbound no longer, the dead are rising again in you, rising and rising, lifted on air.

In summer we consider the whine of the mosquito, the secrecy of the spider, the temper of the wasp — who among us could love you? Who could love even one of you, bearing your poisons and your pain into the heavy summertime air? We could. We could love you if we remind ourselves that no creature is made up only of poison, that no life is only a source of irritation or pain.

We could love the mosquitoes for feeding the chittering chimney swifts wheeling in the sunset, for feeding the tree swallows flying low over the lake at dusk. We could love the spider for spinning the silk that holds together the moss of the hummingbird’s nest, the silk that stretches as the baby birds grow. We could love the wasp for eating the caterpillars that eat the tomato plants. We could love you all if only we remembered the tree swallows and the hummingbirds, if only we remembered the taste of homegrown tomatoes still warm from the sun.

On endless summertime evenings, on cool and generous summertime evenings, let us speak kindly of the red bat, the homely little bat with the smushed face and the hairless infants clinging to her fur by teeth and thumb and feet. In daylight, she dangles one-footed from a tree branch, masquerading as a dead leaf. At nightfall she unfolds her canny wings and skitters to her work, sweeping through the skies, circling under the streetlights, clearing the air of moths whose larvae eat our trees, sweeping up all the whining, stinging creatures we swat at in the dark.

Behold the rat snake gliding silently through the nighttime weeds. Behold the sleek skin, cool but not damp, and the clever darting tongue, sniffing out the contours of the world. Watch as she finds the crack under the toolshed door. Understand that she is finding too the tiny bald mice in the corner of a drawer full of painting rags — the tiny blind mice hidden in the soft remains of ancient bedsheets fallen to ruin.

Pity the young of the poor field mouse, born for just this purpose. Always there are mice — more mice than the world could ever hold if not for a system that includes this beautiful, sinewy creature, this silent celebration of muscle and grace, this serpent serving our uses but too often coming to a brutal end at the end of a hoe.

World, world, forgive our ignorance and our foolish fears. Absolve us of our anger and our error. In your boundless gift for renewal, disregard our undeserving. For no reason but the hope that one day we will know the beauty of unloved things, stoop to accept our unuttered thanks.

3007. Red Light At Night: A Potentially Fatal Attraction to Migratory Bats

By Science Daily, August 26, 2018

Night time light pollution is rapidly increasing across the world. Nocturnal animals are likely to be especially affected but how they respond to artificial light is still largely unknown. In a new study, scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Berlin, Germany, tested the response of European bats to red and white light sources during their seasonal migration.

Soprano pipistrelles (Pipistrellus pygmaeus) and, to a lesser degree, Nathusius' pipistrelles (Pipistrellus nathusii) were recorded more frequently near red LED light, indicating that the animals might be attracted to red light during their migration. In contrast, the scientists did not observe such behaviour near white LED lights. The wavelength of the experimental red LED lights was similar to that of red safety lights used for indicating the presence of wind turbines or tall buildings to aircraft pilots. Warning lights such as these might therefore lure migrating bats precisely towards the danger which the lights help people to avoid. Switching to more bat friendly lights or deploying on-demand lighting -- which only turns on if an airplane approaches -- would most likely reduce bat collisions and bat casualties at wind power stations.

The study has just been published in the scientific journal Ecology and Evolution.

Each year, light pollution increases by around six per cent worldwide. In particular, energy efficient and cheap LEDs are more and more used. Light is an important cue for orientation used by many animals, and also influences their diurnal rhythms and behaviour. It is well established that bats are sensitive to light while hunting at night. While some species are attracted to artificial light sources because of the insects nearby, most bat species generally avoid artificial light. Most previous studies examined the response of bats to artificial light during non-migratory periods. It is already well-known that artificial light causes disorientation in birds that migrate at night. Does the same apply to bats? Many bat species also travel for several hundred or even thousand kilometres during their annual migration, yet we know virtually nothing about their response to artificial light.

During late summer, thousands of bats migrate along the coastline of the Baltic Sea in Latvia, through Pape Nature Reserve. Nights are starlit and largely devoid of light pollution as there are only a few human settlements in the area. Here, the scientists installed an eight metre high pole near the shoreline. A plastic board fixed to the pole was lit-up in 10-minute intervals alternating with darkness. The LED lights illuminating the board switched between red or white LED light. By using ultrasonic microphones the scientists recorded the echolocation calls of bats coming close in order to identify both the species and the number of bats passing by the unlit or lit experimental site.

Soprano pipistrelles (Pipistrellus pygmaeus) and, to a lesser degree, Nathusius' pipistrelles (Pipistrellus nathusii) were recorded more frequently at the experimental site during the red light phase than during darkness. However, bats did not use the artificial light to hunt insects, since the number of hunting echolocation calls remained approximately constant during the light-on periods. "We assume that bats forage for insects early in the night before they continue with their long-distance flight," explains Christian Voigt, lead author of the study. "Also, insects are generally more attracted to short-wave light -- such as ultraviolet light -- than to long-wave red light. Therefore, the displayed light was not attractive for insects." During the white illumination phases, no increase in the number of bats passing the board was observed.

"Bats are at a higher collision risk at wind power stations during their autumn migration. Our study indicates that the use of red light signals could have fatal consequences for them as this appears to attract them to operating wind turbines," explains Oliver Lindecke, co-author of the study. Technological solutions already available could help: "Existing light signals could easily be replaced by bat friendly alternatives, or context-dependent illumination could be deployed which is only activated if planes or helicopters are approaching a wind power plant."

Exactly why bats are attracted to red light sources is unclear. "Bats have excellent eyesight and can even detect wavelengths invisible to us. Some red light sources might potentially blind and disorient them. Whether they then respond by flying towards the source of light with the highest intensity requires further research. It is also absolutely crucial to understand the long-term impact of increasing light pollution on populations of nocturnal animals," explains Christian Voigt. "Many bat species already struggle in our current anthropogenic landscapes characterised by intensive agriculture and high densities of wind turbines. Light pollution is likely to increase pressure on them even further. From a conservation perspective, it is highly advisable that we limit the use of artificial light sources at night to cover only the most pressing and essential human needs. And if there is such an essential need, then bat suitable light sources should be used."

Journal Reference:

1. Christian C. Voigt, Katharina Rehnig, Oliver Lindecke, Gunārs Pētersons. Migratory bats are attracted by red light but not by warm-white light: Implications for the protection of nocturnal migrants. Ecology and Evolution, 2018; DOI: 10.1002/ece3.4400

2945. Mammals Go Nocturnal in Bid to Avoid Humans

By Julia Jacobs, The New York Times, June 15, 2018

A coyote walking across a highway in California. Coyotes in the southern part of the state are increasingly becoming nocturnal to avoid contact with humans traversing their mountain homes, according to a new study. Photo: Justin Sullivan/Getty Images. 

Humans, it turns out, can annoy more than just one another. In fact, some animal populations are escaping their Homo sapien cohabitants by sleeping more during the day, a new study finds.

Mammals across the globe are becoming increasingly nocturnal to avoid humans’ expanding presence, according to the study, published Thursday in Science magazine. The findings show that humans’ presence alone can cause animals across continents — including coyotes, elephants and tigers — to alter their sleep schedules.

“We’re just beginning to scratch the surface on how these behavioral changes are affecting entire ecosystems,” said Kaitlyn Gaynor, an ecologist and graduate student in environmental science at the University of California, Berkeley, who led the study.

Previous research has found that mammals went from being nocturnal to being active during both day and night about 65.8 million years ago, roughly 200,000 years after most dinosaurs went extinct. “Species for millions of years have been adapting to diurnal activity, but now we’re driving them back into the night and maybe driving natural selection,” Ms. Gaynor said in an interview.

The researchers compiled data from 76 studies of 62 species living on six continents in reaching their conclusions. On average, human disruption is making these animals 1.36 times more nocturnal, according to the study.

“For example,” it says, “an animal that typically split its activity evenly between the day and night would increase its proportion of nocturnal activity to 68 percent of total activity near human disturbance.”

In California’s Santa Cruz mountains, for example, coyotes are opting to sleep more during the day in response to recreational human activities such as hiking and bicycling. As a result, coyotes are eating more nocturnal prey, whose waking hours match up more closely with theirs. Recent research such as this was used to provide data for the new study, Ms. Gaynor said. 

Thousands of miles from these night-walking coyotes, tigers living in Nepal at the base of the Himalayas are making similar lifestyle decisions. To avoid contact with humans traversing their favorite forest trails, tigers are increasingly walking the same paths during the night instead, said Neil Carter, who researched this tiger population and co-authored the new study.

This isn’t necessarily a bad thing. “The optimist in me is saying there’s a pathway for coexistence here in an otherwise challenging landscape,” said Dr. Carter, an assistant professor at Boise State University. “What we don’t know is how that might negatively affect tigers.”

Future research might strive to show how these animals’ diets, reproductive patterns and mating behavior are being affected by humans, he said.

Humans do not necessarily need to exhibit violent or blatantly destructive behavior to evoke this fear response in animals; often, our simple presence is enough, Ms. Gaynor said. 

Her own research in Mozambique showed that elephants that typically ate human-grown crops, like maize, were avoiding areas that humans inhabit during the day, but came out after sundown in full force.

Ms. Gaynor said improving technology, such as infrared cameras that can capture vivid images of animals at night and GPS collars that track their whereabouts, have helped to document the trend toward nocturnal existence.

“Working on this study reminds me that we aren’t alone on this planet,” she said. “Being mindful of the ways our activities are shaping the animals habitat will enable coexistence.”

2943. How Wildlife Crossings Are Slowing Down Roadkill

By Tim Lydon, The Revelator, June 8, 2018

Since the Trump administration took office, we haven’t heard much positive news about public-lands protection. But it’s important to remember that good work is still happening. For a timely example, check out Cascade Crossroads, a recent 30-minute documentary highlighting groundbreaking wildlife crossings being built along Interstate 90 in Washington State.

Similar crossings are slowly appearing on highways across the country. Though the transition is slow, it’s encouraging. These crossings will protect wildlife, improve highway safety and connect people to the land for generations. And as the film shows, they offer inspiring tales of collaboration.

Cascade Crossroads illustrates how a diverse coalition worked with the Washington State Department of Transportation and the U.S. Forest Service to bring safe wildlife crossings to a critical section of I-90, Washington’s main east-west traffic corridor.

Snoqualmie Pass overpass, artist’s conception. Credit: WSDOT

The area of focus is a 15-mile stretch of road near Snoqualmie Pass, about 50 miles east of Seattle. It serves as a vital link between eastern and western Washington, carrying goods, commuters as well as skiers and hikers headed to the mountains. Up to 27,000 cars and trucks pass daily.

For wildlife, the road is a deadly gauntlet separating valuable habitats in the Cascade Mountains. Much of the habitat is public lands, including the Alpine Lakes Wilderness north of the highway and Mount Rainier National Park to the south. The lands are shared by an array of species that includes wolverines, bears, elk, deer, lynx, salmon and others.

Each species requires room to roam for survival — to fulfill the daily and seasonal needs of finding food, rearing young, denning and mating. These activities are necessary to keeping populations healthy. But at Snoqualmie Pass, development to the east and west confines wildlife to a narrow bottleneck, which is then sliced in half by I-90.

It is a common scenario nationwide.

At Snoqualmie Pass, biologists found some that animals are deterred by the mere sight and sound of the highway, leaving them hemmed into ecologically limited “islands” of habitat. Others are compelled to cross the road. As a result, a common sight alongside I-90 is the battered corpse of a deer, fox or other animal — each an offspring, mate or maybe a parent seeking food for its young.

The deaths are not just a casualty of Washington’s highway; they are a symptom of a national problem. Research indicates that millions of animals are killed each year on American roads. The accidents also cause up to 200 human fatalities annually and billions of dollars in property damage, not to mention the harm to individual species.

In Washington, the problem could have gotten even worse with a planned highway repair and expansion near Snoqualmie Pass. The project threatened adjacent national forest lands.

To try to mitigate wildlife deaths and advocate for safe wildlife passages, conservationists formed the I-90 Wildlife Bridges Coalition. It included Conservation Northwest, the Audubon Society and many others that had worked in Washington for decades. They engaged the public and brought together diverse interests, including highway safety advocates such as the American Automobile Association.

It did not happen quickly or easily, but the coalition, the Forest Service and the Washington Department of Transportation worked together to build trust and share knowledge. Over years, as shown in the film, conservationists learned about the realities of highway engineering, while transportation officials learned about the possibilities for wildlife-friendly roads. They were encouraged by agency leaders willing to take risks and biologists and engineers who melded their expertise into tangible proposals.

All sides compromised.

In the end, their proposal for dozens of wildlife underpasses and two wildlife overpasses   garnered broad public support. Lawmakers funded the proposal after being petitioned by engineers, conservationists and highway safety groups standing shoulder-to-shoulder.

The project is now underway, and Cascade Crossroads highlights its early accomplishments. One bridge was expanded to span not just the width of a river but also 1,000 feet of surrounding wetlands biologists had identified as critical for wildlife movement. Culverts were widened to allow fish, amphibians and other animals to pass. Steel and concrete structures are taking shape to create a fully vegetated wildlife overpass.

Meanwhile, volunteers have planted shrubs and created other features that will entice wildlife toward the crossings. University students and agency biologists monitor wildlife cameras that show animals already safely using the new routes.

2823. This Mutant Crayfish Clones Itself

By Carl Zimmer, The New York Times, February 5, 2018

The marbled crayfish is a mutant species that clones itself, scientists report. The population is exploding in Europe, but the species appears to have originated only about 25 years ago.  Photo: Ranja Andriantsoa.

Frank Lyko, a biologist at the German Cancer Research Center, studies the six-inch-long marbled crayfish. Finding specimens is easy: Dr. Lyko can buy the crayfish at pet stores in Germany, or he can head with colleagues to a nearby lake.

Wait till dark, switch on head lamps, and wander into the shallows. The marbled crayfish will emerge from hiding and begin swarming around your ankles.

“It’s extremely impressive,” said Dr.

Over the past five years, Dr. Lyko and his colleagues have sequenced the genomes of marbled crayfish. In a study published on Monday, the researchers demonstrate that the marble crayfish, while common, is one of the most remarkable species known to science.

Before about 25 years ago, the species simply did not exist. A single drastic mutation in a single crayfish produced the marbled crayfish in an instant.

The mutation made it possible for the creature to clone itself, and now it has spread across much of Europe and gained a toehold on other continents. In Madagascar, where it arrived about 2007, it now numbers in the millions and threatens native crayfish.

“We may never have caught the genome of a species so soon after it became a species,” said Zen Faulkes, a biologist at the University of Texas Rio Grande Valley, who was not involved in the new study.

The marbled crayfish became popular among German aquarium hobbyists in the late 1990s. The earliest report of the creature comes from a hobbyist who told Dr. Lyko he bought what were described to him as “Texas crayfish” in 1995.

The hobbyist — whom Dr. Lyko declined to identify — was struck by the large size of the crayfish and its enormous batches of eggs. A single marbled crayfish can produce hundreds of eggs at a time.

Soon the hobbyist was giving away the crayfish to his friends. And not long afterward, so-called marmorkrebs were showing up in pet stores in Germany and beyond.

As marmorkrebs became more popular, owners grew increasingly puzzled. The crayfish seemed to be laying eggs without mating. The progeny were all female, and each one grew up ready to reproduce.

In 2003, scientists confirmed that the marbled crayfish were indeed making clones of themselves. They sequenced small bits of DNA from the animals, which bore a striking similarity to a group of crayfish species called Procambarus, native to North America and Central America.

Ten years later, Dr. Lyko and his colleagues set out to determine the entire genome of the marbled crayfish. By then, it was no longer just an aquarium oddity.

For nearly two decades, marbled crayfish have been multiplying like Tribbles on the legendary “Star Trek” episode. “People would start out with a single animal, and a year later they would have a couple hundred,” said Dr. Lyko.

Many owners apparently drove to nearby lakes and dumped their marmorkrebs. And it turned out that the marbled crayfish didn’t need to be pampered to thrive. Marmorkrebs established growing populations in the wild, sometimes walking hundreds of yards to reach new lakes and streams. Feral populations started turning up in the Czech Republic, Hungary, Croatia and Ukraine in Europe, and later in Japan and Madagascar.

Sequencing the genome of this animal was not easy: No one had sequenced the genome of a crayfish. In fact, no one had ever sequenced any close relative of crayfish.

Dr. Lyko and his colleagues struggled for years to piece together fragments of DNA into a single map of its genome. Once they succeeded, they sequenced the genomes of 15 other specimens, including marbled crayfish living in German lakes and those belonging to other species.

The rich genetic detail gave the scientists a much clearer look at the freakish origins of the marbled crayfish.

It apparently evolved from a species known as the slough crayfish, Procambarus fallax, which lives only in the tributaries of the Satilla River in Florida and Georgia.

The scientists concluded that the new species got its start when two slough crayfish mated. One of them had a mutation in a sex cell — whether it was an egg or sperm, the scientists can’t tell.

Normal sex cells contain a single copy of each chromosome. But the mutant crayfish sex cell had two.

Somehow the two sex cells fused and produced a female crayfish embryo with three copies of each chromosome instead of the normal two. Somehow, too, the new crayfish didn’t suffer any deformities as a result of all that extra DNA.

It grew and thrived. But instead of reproducing sexually, the first marbled crayfish was able to induce her own eggs to start dividing into embryos. The offspring, all females, inherited identical copies of her three sets of chromosomes. They were clones.

Now that their chromosomes were mismatched with those of slough crayfish, they could no longer produce viable offspring. Male slough crayfish will readily mate with the marbled crayfish, but they never father any of the offspring.

In December, Dr. Lyko and his colleagues officially declared the marbled crayfish to be a species of its own, which they named Procambarus virginalis. The scientists can’t say for sure where the species began. There are no wild populations of marble crayfish in the United States, so it’s conceivable that the new species arose in a German aquarium.

All the marbled crayfish Dr. Lyko’s team studied were almost genetically identical to one another. Yet that single genome has allowed the clones to thrive in all manner of habitats — from abandoned coal fields in Germany to rice paddies in Madagascar.

In their new study, published in the journal Nature Ecology and Evolution, the researchers show that the marbled crayfish has spread across Madagascar at an astonishing pace, across an area the size of Indiana in about a decade.

Thanks to the young age of the species, marbled crayfish could shed light on one of the big mysteries about the animal kingdom: why so many animals have sex.

Only about 1 in 10,000 species comprise cloning females. Many studies suggest that sex-free species are rare because they don’t last long.

In one such study, Abraham E. Tucker of Southern Arkansas University and his colleagues studied 11 asexual species of water fleas, a tiny kind of invertebrate. Their DNA indicates that the species only evolved about 1,250 years ago.

There are a lot of clear advantages to being a clone. Marbled crayfish produce nothing but fertile offspring, allowing their populations to explode. “Asexuality is a fantastic short-term strategy,” said Dr. Tucker.

In the long term, however, there are benefits to sex. Sexually reproducing animals may be better at fighting off diseases, for example.

If a pathogen evolves a way to attack one clone, its strategy will succeed on every clone. Sexually reproducing species mix their genes together into new combinations, increasing their odds of developing a defense.

The marbled crayfish offers scientists a chance to watch this drama play out practically from the beginning. In its first couple decades, it’s doing extremely well. But sooner or later, the marbled crayfish’s fortunes may well turn.

“Maybe they just survive for 100,000 years,” Dr. Lyko speculated. “That would be a long time for me personally, but in evolution it would just be a blip on the radar.”

2821. Large-Group Living Boosts Magpie Intelligence

By Science Daily, February 7, 2018

Australian magpies

Growing up in a large social group makes Australian magpies more intelligent, new research shows.

Using four tasks to test intelligence, scientists from the University of Exeter and the University of Western Australia found wild Australian magpies from larger groups showed "elevated cognitive performance."

The study also found more intelligent females produced more offspring.

The research suggests that the demands of living in complex social groups may play a role in the evolution of intelligence.

"Australian magpies -- from Western Australia, where we conducted our research -- live in stable social groups," said Dr Alex Thornton, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall.

"We showed that individuals living in larger groups in the wild show elevated cognitive performance, which in turn is linked to increased reproductive success.

"Repeated testing of juveniles at different ages showed that the link between group size and intelligence emerged in early life."

Researchers examined 14 wild groups of Australian magpies (Western Australian subspecies Cracticus tibicen dorsalis) in Perth, ranging in size from three to 12 birds.

Cognitive ability of each magpie was tested using four tasks, including one in which they had to learn to associate a particular colour with the presence of food, a memory task where food was hidden in the same place many times.

There was also a test of self-control, in which magpies had to stop themselves from pecking directly at the food through the transparent barrier and instead had to go round to the sides of the tube to get the food.

Lead researcher Dr Ben Ashton, from the University of Western Australia, said: "The challenges of living in complex social groups have long been thought to drive cognitive evolution.

"However, evidence to support this is contentious, and has recently been called into question."

He added: "Our results suggest that the social environment plays a key role in the development of cognition.

"They also suggest that females who do well in cognitive tasks have more offspring, indicating there is the potential for natural selection to act on cognition.

"Together, these results support the idea that the social environment plays an important role in cognitive evolution."

---

Journal Reference:

1. Benjamin J. Ashton, Amanda R. Ridley, Emily K. Edwards, Alex Thornton. Cognitive performance is linked to group size and affects fitness in Australian magpies. Nature, 2018; DOI: 10.1038/nature25503

2627. Documentary: Murder of Crows

By PBS, July 19, 2016

2510. Giraffes, Towering and Otherworldly, Are ‘Vulnerable’ to Extinction

By Patrick Healy, The New York Times, December 8, 2016

The majestic giraffe, the world’s tallest land mammal and a prime attraction at zoos worldwide, is threatened with extinction because of illegal hunting and a loss of its habitat, according to a report published on Thursday by an international monitoring group.

The giraffe population has declined by 40 percent over the past three decades and now stands at about 97,600, according to the findings by the International Union for the Conservation of Nature, which designates endangered species.

While the largest giraffe populations reside in national parks and reserves, those protected areas have proved to be inadequate, one of several alarming conclusions about the animals’ future in the group’s latest Red List of Threatened Species report.

“While global attention has been on threats to elephants and rhinos, giraffes have been off the radar, and we’ve been losing them in significant numbers,” said Liz Bennett, the vice president for species conservation for the Wildlife Conservation Society, which was not involved in the report. “People and governments need to start acting to save giraffes, fast.”

With their soaring heights of up to 20 feet and their stunning necks, which are typically about six feet long, giraffes have long been the stuff of dreams — for children who love to draw them and for adults who retain an awe for the otherworldly creatures. Their tongues can extend a foot or more, making feeding times an especially popular sight at zoos and on safari.

Yet the animals’ rare size and regal visage have made them a prime target of poachers in Africa, who drop steel-wire snares from tree canopies or stalk and shoot giraffes with rifles, wildlife experts say.

The threat to giraffes is so great that the Red List upgraded the species from the “least concern” category to “vulnerable,” skipping over the intermediary “near-threatened” designation. Graver categories include “critically endangered,” “extinct in the wild” and, ultimately, “extinct.”

The animals are divided into nine subspecies; according to the Red List report, five have decreasing populations, three are on the increase, and one is stable.

One bright spot: The numbers of West African giraffes are on the rise, numbering about 400 now, up from 50 in the 1990s. This remains the smallest of the subspecies.

Asked if it was possible for giraffes to become extinct in the wild in the next 20 years if nothing is done, Derek Lee, an ecologist who contributed to the Red List report, paused for several moments during a phone interview on Thursday from Tanzania. He then said, “I think we’d see drastic declines at the very least.”

Giraffes are found mostly in southern and eastern Africa, with smaller populations in West and Central Africa. Some of those populations are particularly vulnerable because of war and other civil unrest in countries on the Continent, like Sudan.

Poaching and the loss of habitat are “equally dangerous threats that vary in degree from place to place,” said Dr. Lee, who is a founder of the Wild Nature Institute. While governments and organizations could take stronger actions against poaching by enforcing laws and animal protection rules, habitat loss can be harder to stop because it involves curbing economic activity, such as land development, mining and scavenging.

“These are problems everywhere for giraffes,” Dr. Lee said. “You need to stop both threats.”

The threat to giraffes is not expected to affect their numbers at zoos in New York and other cities around the world, wildlife specialists said, because zookeepers have a good record helping the animals with reproduction.

Still, zoo leaders are likely to consider changing signs at their exhibits to stress the animals’ vulnerability to extinction as a way to raise public awareness.

“That would be the best way to get the word out to people that we need to do more to protect these animals,” said Dr. Bennett, of the conservation society, which runs the Bronx Zoo, the New York Aquarium and other zoos in the city.

2347. Weasels Are Built for the Hunt

By Natalie Angier, The New York Times, June 13, 2016

At birth, the least weasel is as small and light as a paper clip, and the tiny ribs that press visibly against its silvery pink skin give it a segmented look, like that of an insect. A newborn kit is exceptionally underdeveloped, with sealed eyes and ears that won’t open for five or six weeks, an age when puppies and kittens are ready to be weaned.

A mother weasel, it seems, has no choice but to deliver her young half-baked. As a member of the mustelid clan — a noble but often misunderstood family of carnivorous mammals that includes ferrets, badgers, minks and wolverines — she holds to a slender, elongated body plan, the better to pursue prey through tight spaces that most carnivores can’t penetrate. Bulging baby bumps would jeopardize that sylphish hunting physique.

The solution? Give birth to the equivalent of fetuses and then finish gestating them externally on mother’s milk.

“If you want access to small environments, you can’t have a big belly,” said William J. Zielinski, a mustelid researcher with the United States Forest Service in Arcata, Calif. “You don’t see fat weasels.”

For Dr. Zielinski and other mustelid-minded scientists, weasels exemplify evolutionary genius and compromise in equal measure, the piecing together of exaggerated and often contradictory traits to yield a lineage of fierce, fleet, quick-witted carnivores that can compete for food against larger celebrity predators like the big cats, wolves and bears.

Researchers admit that wild mustelids can be maddening to study. Most species are secretive loners, shrug off standard radio collars with ease, and run close to the ground “like small bolts of brown lightning,” as one team noted. Now you see them, no, you didn’t.

Nevertheless, through a mix of dogged field and laboratory studies, scientists have lately made progress in delineating the weasel playbook, and it’s a page turner, or a page burner.

Researchers have been astonished to discover that the average mustelid is like a fur-covered furnace, its metabolic rate exceeding not only that of other carnivorous mammals but also that of its twitchy, ever-gnawing rodent prey.

“If you compare a least weasel to a meadow mouse, they’re the same weight, but the weasel has the higher metabolic rate,” said Roger Powell, an emeritus professor at North Carolina State University and doyen of weasel studies.

“The weasel heart beats at up to 400 pulses per minute,” said Mark Linnell, a faculty research assistant who studies mustelids at Oregon State University. “They’re geared to run at full speed, and they’re always high-strung.”

That keyed-up metabolism is another example of a grand mustelidian compromise. “If you have a high metabolic rate, you can be more active and search farther for food in more places and in more diverse ways,” Dr. Powell said. “But you have to catch more food in order to do that.”

Big cats must eat the equivalent of roughly a third of their weight each week; weasels must eat a third or more of their weight each day. “They’re living life on the edge,” Dr. Powell said.

Weasels also have big brains relative to body mass, and they apply their neuronal bounty to continuously fine-tune their movements during a hunt, a strategy that allows them to attack prey up to 10 times their size.

The fisher, a particularly fearless weasel in the marten branch, may be the only North American carnivore to have mastered the art of dining on adult porcupine — a large rodent that, in addition to being protected by a formidable quill sheath, weighs a good 12 pounds more than the eight-pound fisher.

“It’s got to be one of the great predator-prey matchups in history,” said Roland Kays, a biologist at the North Carolina Museum of Natural Sciences and North Carolina State. The fisher must encounter the porcupine on open ground, at which point it can start running circles around its quarry. The fisher tries to dart in and bite the porcupine’s vulnerable face; the porcupine pivots to turn its shielded back toward its attacker. Dart and spin, dart and bite.

After several deep wounds to its face, the porcupine grows weak, loses its footing and — match over. The fisher will then flip the punctured, pincushioned animal onto its back and carefully tear into a quill-free patch of belly, gaining access to desirable organs like the small intestine, which is not only rich in protein and lipids, but also contains the partially digested plant matter that even carnivores need.

Dr. Kays and a former student, Scott LaPoint, have found that fishers are far more behaviorally flexible than biologists had thought possible, at least in the Northeast. Hunted and trapped to near extinction until the 1930s, fishers — a misleading name derived from Dutch colonists’ word for polecat, a European weasel — began recovering in their traditional setting of deep forests, where they could easily avoid humans.

In the last few years, though, the weasels have apparently shaken off their reserve and begun showing up in suburban and urban areas — a shopping mall in Schenectady, N.Y., a parking lot in downtown Albany. Two years ago, a sizable male fisher made its way to the Bronx, startling anybody who saw it slinking along the sidewalk and raising hope that a solution to the city’s rat problem might have finally arrived.

The fisher, alas, soon disappeared. “I don’t know how that one ended up in the Bronx in the first place,” Dr. Powell said, “but it’s no place for a fisher, and I’m sure he wished he’d turned left when he turned right.”

For their part, researchers wish they could overturn the public’s generally poor opinion of weaseldom. To call someone a weasel means the person is shifty, untrustworthy. Weasel words are those squishy, defensive qualifiers beloved by, well, journalists.

In a recent “Brewster Rockit: Space Guy” comic strip, a “closet of nightmares” is opened to reveal, “AAHHH!!! Weasel-juggling clowns!”

Researchers speculate that the negative image may result partly from the mustelid’s serpentine silhouette: In some parts of Central America, weasels are called “furry snakes.” Or maybe it’s the distinctive mustelid musk. Most weasel species communicate with one another over large home ranges through frequent daubs of a pungent fluid excreted by their anal glands.

Shihab Shamma, who uses ferrets to study the mammalian auditory system at the University of Maryland and Descartes University in Paris, said of the ferrets at his Paris lab, “We give them the names of smelly French cheeses.”

But mustelid enthusiasts emphasize the family’s beauty and diversity: some 60 living species across all continents except Antarctica and Australia, ranging in size from the least weasel, the world’s smallest carnivore (weighing less than half a stick of butter as an adult), to the mighty wolverine, which can weigh up to 70 pounds.

Many weasels spend time in water, and one species, the sea otter, is a marine mammal that rarely comes on land. Sea otters are also among the only nonprimate mammals to use tools, cracking open a recalcitrant mollusk shell by banging it with a stone. Most of the time, though, the sea otter’s teeth do the job.

“Their teeth are amazing, like no other living carnivore,” said Adam Hartstone-Rose, who studies mammalian bite forces at the University of South Carolina. “They’re big and rounded and with no pointy cusps that might break off. They look like pillows or gum drops.” But the teeth, with their thick coat of enamel, can easily crush open a crab, clam or snail.

Most weasels have dentition more typical of carnivores, with a few sharp, slicing teeth and fewer, smaller molars, which other animals use to grind plants. As a result of their compact dental layout, many weasels have foreshortened snouts that make them look young and cute. They can also act young: Weasels are among the few animals that play as adults.

If they’re well fed, Dr. Powell said, “they’ll bounce and ricochet around, pounce, stalk, wiggle and change shape and just about turn themselves inside out. They put kittens to shame.”

Many weasels live in cold places, and because their long, thin shape has a high surface area relative to volume, they lose heat easily. To tackle the cold without relying on fat as an insulator, many weasels grow luxurious fur coats, some of the densest in nature.

A good head of human hair has about 350 hairs per square inch. On a mink, the fiber count per square inch is 44,000. Small wonder that people have historically coveted weasel pelts — mink, sable and ermine, the fur of pomp and royalty taken from the animals in winter, when their coats turn white.

Weasels also appreciate the value of co-opted fur. In winter, voles and mice build little dome-shaped nests under the snow. When a weasel finds one of these nests, it’s a genuine jackpot: lunch and lodging combined. Better still with a few tweaks: After eating the residents, the weasel lines its new dwelling in rodent fur to improve insulation.

“If you pop open one of these nests in springtime, you discover a macabre scene,” Dr. Zielinski said. “What was once occupied by a vole is now covered with vole-hair wallpaper.”

A rodent’s closet of nightmares: no clowns, no juggling, just one cold and hungry weasel, knocking at the door.