Science Friday® is produced by the Science Friday Initiative, a 501(c)(3) nonprofit organization.
If carbon dioxide levels continue to rise, we likely have a long thaw ahead of us.
The sea otter is one of few species of mammals, on land or in the sea, that uses tools -- an ability that at one time was thought to be possessed only by humans.
While the more familiar North American beaver sports a spanking big tail, which serves variously as a rudder, a prop, a fat store, and a communication device, the mountain beaver gets along just fine with its stunted and furry rear appendage.
The Australian green tree frog has big eyes, a friendly demeanor, and a bit of a pot belly, all of which bring to mind certain traits of Muppet star Kermit the Frog.
Dr. Seuss's McElligot's Pool (1947) features some fantastic fish—ones with pinwheel-like tails, curly noses, long floppy ears, or Kangaroo pouches. The fictional fish do have some truly strange nonfictional cousins, among which are giant oarfish, barreleye fish, and sawfish.
In North America, the mystical and majestic ash is suffering from infestation with the invasive emerald ash borer, and in Europe it is battling the fungus Chalara fraxinea.
Running buffalo clover produces a single, spiked flower, one that is quintessentially clover. But unlike other clovers, running buffalo is endangered -- it was once even thought to be extinct, for reasons that are reflected in its name.
Stony corals can vomit digestive filaments on their neighbors to disintegrate competitors for space and light.
The endangered Stephen's kangaroo rat actually is not a rat -- it is more closely related to rodents such as squirrels and gophers than it is to notorious pests like the Norway rat and house rat.
Like many other species of subalpine and alpine wildflowers, each year, as the winter snowpack recedes, the glacier lily comes to life, sprouting leaves and flowers as soon as conditions are favorable and taking advantage of every moment of the short growing season.
Introduced populations of European rabbits have led to the extinction of native animals and threaten species of native plants.
That the tiny hemlock woolly adelgid is killing off old-growth hemlock trees -- many of which measure at least three feet in diameter and stretch upwards of 100 feet in height -- seems improbable.
More than half the world's population now lives in urban areas, which means that, combined with the loss of nature from urban sprawl, fewer children than ever have the chance to walk out their back doors and into a natural world of discovery.
Do Arctic wolves use cooperative hunting strategies?
The Delmarva fox squirrel is a very, very large squirrel. It can tip the scales at as many as three pounds.
Down to just 167 singing males in 1987, the Kirtland's warbler population has rebounded, with 1,828 males counted in 2011. The species has risen, almost literally, like a phoenix from the ashes.
The jackdaw's intelligence and curiosity perpetuate the bird's tendency to get into trouble.
In the United States, 26 species of snails are listed as endangered.
The numbat, aka the banded anteater, is a marsupial native to Australia.
Street canyons--narrow streets lined by buildings hundreds of feet tall--are unique to the urban landscape. But while their structure undoubtedly adds to the allure of cities, it also effectively traps pollutants emitted by vehicular traffic traversing the canyon floor, resulting in poor air quality.
That we can “catch” yawns is in itself fascinating, but that we can’t catch them from just anyone -- that we are immune to the yawns of perfect strangers but highly susceptible to those of family members or friends -- makes this behavior all the more intriguing.
There are major hindrances to prioritizing biodiverse areas for conservation. Examples include determining the size of land area that must be set aside, which generally must be very large to ensure that ecosystems can maintain their functions, and determining the value of these places in economic terms.
The global value of plant-based medicines is most readily apparent in revenue generated from sales of over-the-counter herbal preparations. In 2005 more than $14 billion (USD) was spent on such remedies in China alone. In 2007 US citizens spent even more -- nearly $15 billion -- on over-the-counter natural products.
Deciphering the DNA sequence of the human fetal genome, without penetrating the womb, was considered impossible. But in a recent breakthrough, University of Washington geneticists Jacob O. Kitzman and Jay Shendure, working with colleagues in the United States and Italy, not only successfully sequenced the fetal genome, but they did so using genetic clues teased from the readily accessible reservoirs of maternal blood and paternal saliva.
While epiphytes are defined by their growth on other plants, most commonly trees, they do not steal nutrients away from their hosts. Rather, they rely on specialized aerial root systems that absorb water and nutrients directly from the air.
There are few animals in the world that share the morphological peculiarities of turtles, and the physical likenesses that do exist between these shelled wonders and other animals are so ambiguous as to be considered one of the last great obstacles to a more complete understanding of not only the turtle's evolutionary past but also the whole of vertebrate evolution.
The brown mouse lemur is one of the smallest primates in the world. It also has the distinction of being the only animal that is parasitized bya particular species of blood-sucking louse that recently found itself at the center of a scientific effort to map the social network of its elusive host.
The circadian clock is a biological timekeeper. As it ticks through its 24-hour cycle, some 10 to 15 percent of our genes dance to its beat, stirring us to wake and eat and lulling us to sleep. Remarkably, this complex dance is choreographed by only a handful of master regulatory genes, two of which recently were found to not only regulate clock activity but also influence the metabolism of nutrients.
J. heathi and O. banksii appear to have remarkable control over their cloaking response to light.
The frozen seawater of the Arctic and Antarctic seems uninhabitable. Yet, within these cold, salty formations, there exists an amazing array of microorganisms, from algae and fungi to bacteria, archaea, and protozoans. Together, these organisms make up the sea-ice microbial community, a remarkable alliance of diverse life-forms unified by the common theme of extreme adaptation, which enables them to thrive and makes them important members of the larger sea-ice ecosystem.
Victory is sweet, so much so that we often feel compelled to rejoice with a cry of triumph. For some animals, that cry not only announces a win to all those within earshot but also serves surprisingly complex social functions. Take, for instance, the call of the victorious little blue penguin (Eudyptula minor), which a recent study in the journal Animal Behavior revealed has a direct effect on the behavior of “social eavesdroppers” -- penguins who, from the safety of their burrows, assess the quality of fighting individuals based solely on their vocalizations.
Chevrotains have two-toed hooves and specialized stomachs that allow them to regurgitate and chew on partially digested plant matter to help breakdown undigestible cellulose -- characteristics that classify them as ruminants. Chevrotains, however, are the most primitive ruminants alive today, as evidenced by their lack of horns or antlers, their long upper canine teeth, and their three-chambered stomachs (as opposed to the typical four-chambered anatomy of other ruminants). These features, along with certain pig-like characteristics, have led some scientists to conclude that chevrotains form an evolutionary link between ruminants and nonruminants, or animals with single-chambered stomachs, such as pigs and humans.
Gliding mammals sail silently from one tree to the next, maneuvering to their destinations with extraordinary precision and control, often in complete darkness. This unique ability is found in only about 60 species of mammals in the world, but those species include marsupials and placental animals, two very distantly related groups distinguished by the vast evolutionary differences in their reproductive systems. As a result, gliding mammals serve as a fascinating example of convergent evolution -- when similar physical and functional traits occur in unrelated species.
The southern house mosquito (Culex quinquefasciatus) arrived in Hawaii in the 1820s, its larvae likely entering the local water supply when contaminated water casks aboard a sailing vessel were dumped at the port of Maui. Up to that time, mosquitoes had been nonexistent on the islands, and hence native birds had evolved in environments without mosquito-borne disease, leaving them with no innate defense against infection. As a result, the arrival of avian pox (in the 1800s) and avian malaria (in the early 1900s), both of which are transmitted by Culex and presumably reached the islands in nonnative birds transported on ships, facilitated the near decimation of Hawaii’s forest birds.
Community structure in ecology is defined by species richness and population abundance, characteristics that some scientists have argued are produced by unrelated, chance processes. But new research by a team of scientists in Germany and the United States has taken chance out of the biodiversity equation. After uncovering similarities in the community structure of tropical forests in three regions of the world, the scientists concluded that species richness and abundance must be governed by related, deterministic processes, including predation and disease.
The continued increase of atmospheric carbon suggests that by the end of this century the world’s oceans, which absorb 25 percent of our carbon dioxide emissions, could contain twice as much of the greenhouse gas as they do now. Such a steep rise could have significant impacts on some species of marine fish, since the introduction of more carbon dioxide turns seawater acidic and dramatically alters the animals’ sensory response -- changes that a new report published in the journal Nature Climate Change indicates are mediated by a chemical receptor in the brain known as GABA-A.
Lilliputian life is all around us -- in trees and water, or as a team of U.S. scientists recently reported, in leaf litter on the forest floor. Indeed, it was beneath the leaves in the lowland rainforests of eastern Papua New Guinea where they discovered two new species of tiny frogs. The most diminutive of the two, at 7 to 8 mm in length, claims the title of world’s smallest vertebrate, and its discovery raises intriguing questions about the limits of extreme body size.
Pheidole ants, of which there are more than 1,100 known species, making the genus one of the largest in the taxonomic system, are known for their extraordinary diversity. And among their sundry forms is a “supersoldier” subcaste, a rare group of ant sumo wrestlers. But as a team of scientists from Europe, Canada, and the United States has discovered, although supersoldiers are produced by just a few Pheidole species and thus are infrequent in nature, all Pheidole ants have the potential to produce them, and they have possessed this ability since the genus evolved some 35 to 60 million years ago.
Badwater Basin in Death Valley sits 282 feet below sea level and is known for its extensive salt flats and brackish water. The harsh environment is forbidding to all but the specially adapted and salt-tolerant. And recently added to its collection of atypical life-forms is a group of greigite-producing magnetic bacteria, which were isolated from a sample of brackish spring water and described in a report published in Science in late December.
Fin whales are enormous animals, with the largest individuals measuring nearly 90 feet in length and weighing 80 tons. Something that large should be conspicuous, especially in the coastal waters where fin whales spend much of their time. But the species’ propensity to disperse to open water and steep declines in its numbers in the 20th century have rendered it a rare sight. And so, relative to its famous baleen cousins, the blue whale and the humpback, the fin whale is lesser known, and its behavior little understood.
With a black button nose, large round eyes, and fuzzy knobs of ears, the least weasel is undoubtedly adorable. And it is made all the more so by its small size, with the tiniest individuals weighing just 25 grams and measuring a mere four inches in length. But beneath the fur and the lanky little profile lies a fierce meat-hungry predator, a bantamweight killer that carries a reputation as the world's smallest carnivore*.
Around 20,000 years ago, as the Last Glacial Maximum—the world's last significant glacial period—was coming to a close, Earth began to change dramatically. The climate warmed, large ice sheets began to melt, and humans crept increasingly into northern latitudes. At the same time, large mammals, or megafauna, such as woolly mammoths, woolly rhinoceros, and cave lions, were disappearing. In the end, North America lost 72 percent of its megafauna, and Eurasia 36 percent.
Space explorers and science fiction authors have long dreamed of space colonization, of the day when the human species will inhabit distant planets. Habitable planets, however, lie beyond the roughly 1,200-mile-boundary of low Earth orbit (LEO), which humans have not flown past since the final Apollo mission in December 1972. Beyond-LEO travel poses significant challenges to human survival—problems that researchers are now addressing through studies in space with the worm Caenorhabditis elegans, an organism that shares 40 to 50 percent genetic similarity with humans and hence offers insight into potential impacts of distant space travel on human physiology.
The color of a fossil species is often its greatest secret, its pigmented tissues having decayed and returned to the earth long before its discovery. An anomaly in this pattern was the recent reconstruction of wing coloration from color-producing structures discovered in the wing scales of 47-million-year-old fossil lepidopterans (moths and butterflies) recovered from the Grube Messel oil shales in Germany.
On the open lands of sub-Saharan Africa, the world's only terrestrial bird of prey, the long-legged secretary bird (Sagittarius serpentarius), stalks across the ground, sometimes walking as many as 20 miles in a single day in search of quarry.
Plumes of hot water gush upward from chimney-like structures in the floor of the mid-Atlantic Ocean, turning black as the sulfide minerals they contain mix with the cold surrounding water. Known as black smokers, such hydrothermal vents are signs that the violent, molten world that exists beneath Earth’s surface is still very much active. And amazingly, alive within this mercurial environment, is a microorganism known as Pyrolobus fumarii, the “fire lobe of the chimney.”
In the dark depths of a limestone cave in Sai Yok National Park, a tiny bat hangs effortlessly from the ceiling, resting, waiting for sunset, when it will take flight and embark on its nightly foraging expedition. It will not be out for long -- indeed, this bat, the bumblebee bat (Craseonycteris thonglongyai), needs only a few small insects to satisfy its appetite. It is, after all, a mere two grams in weight and a little over an inch in length, making it one of the world's smallest mammals.
For an animal that stands as tall as 7 feet at the shoulder and weighs as many as 1,500 pounds, the moose has an uncanny ability for slipping silently into forest shadows and escaping notice. But in areas of Montana and western Wyoming, moose themselves are becoming shadows. Indeed, in those states, herds of the Shiras moose (Alces alces shirasi) are shrinking, and with no clear explanation why and no way of stopping the decline, biologists are concerned that some herds may soon vanish entirely.
Chirping from the talus slopes of the Teton Range in the Rocky Mountains, the American pika (Ochotona princeps) sends a warning call to intruders -- in this case humans climbing up the switchbacks in Grand Teton National Park's Cascade Canyon. Sounding its alarm from a rocky perch, then darting into crevices and shadow on the steep slope, the rodent-sized, round-eared, brownish gray pika goes largely unnoticed. But as the second species petitioned for protection under the U.S. Endangered Species Act (ESA) because of climate change-associated threats (the polar bear was the first), the pika cannot afford to be overlooked for much longer.
To access older blog posts, navigate via the archive links in the sidebar at left.