This could be embarrassing for rattlesnakes and other vipers: Their long-standing reputation as the snakes with the fastest strikes on Earth just got bit by the common Texas rat snake.

In lab tests biting a stuffed glove, Western rattlesnakes averaged speeds of 2.95 meters per second and Western cottonmouths averaged 2.98 m/s, says functional morphologist David Penning of the University of Louisiana at Lafayette. But Texas rat snakes, familiar farmyard chasers of pest rodents, averaged 2.67 m/s. Statistically that’s a three-way tie, Penning and his colleagues report March 16 in Biology Letters.

Strikes were over quickly but all species subjected their brains to impressive acceleration. Rat snakes accelerated their head more on average (190 meters per second2)
than what a fighter pilot experiences when taking off from an aircraft carrier (27 to 49 m/s 2 ).
Penning’s point is not that vipers are slow, but that other snakes also evolved a lightning strike. “They have to eat too,” he says. Startled mammals have been clocked activating a muscle in as little as 14 to 151 milliseconds. Snakes in Penning’s tests reached their targets in 50 to 90 milliseconds, literally before some creatures could move a muscle. And if you blink — for a human average of 220 milleseconds — you miss it all.

For corals, baby fat is food. Coral mothers send their offspring into the world with a balanced meal of fat and algae, but baby corals mainly chew the fat, new research finds.

Adult corals of the species Pocillopora damicornis get most of their nutrition from symbiotic algae that live inside them, providing metabolic energy by photosynthesis. But coral larvae, researchers report online March 25 in Science Advances, rely instead on their “baby fat.”

The finding sheds light on corals’ metabolism during their most vulnerable developmental stage, says biological geochemist Anders Meibom of École Polytechnique Fédérale de Lausanne in Switzerland. Baby fat “is a good thing,” he says. “It gives the coral some time to find a good home without running out of juice.” Larvae’s dependence on fat may make them less sensitive to bleaching — a process in which stressed corals jettison their algal tenants and eventually starve to death. So understanding larval nutrition could help scientists better understand the effects of ocean warming and acidification on bleaching, Meibom says.
Meibom and colleagues fed isotope-tagged nutrients to larvae of P. damicornis, commonly called cauliflower coral, and tracked how the larvae’s symbiotic algae used the nutrients over time. Algae are less abundant in larvae compared with adult corals and provide very little energy, the researchers found.

The next step is to pinpoint exactly when and how larvae switch from feeding on fat to algae as they transition into adulthood, Meibom says, as well as exploring how Earth’s changing oceans might impact the process.

NEW YORK — Cells in a brain structure known as the hippocampus are known to be cartographers, drawing mental maps of physical space. But new studies show that this seahorse-shaped hook of neural tissue can also keep track of social space, auditory space and even time, deftly mapping these various types of information into their proper places.

“The hippocampus is an organizer,” says neuroscientist Howard Eichenbaum of Boston University.

Neuroscientist Rita Tavares described details of one of these new maps April 2 at the annual meeting of the Cognitive Neuroscience Society. Brain scans had previously revealed that activity in the hippocampus was linked to movement through social space. In an experiment reported last year in Neuron, people went on a virtual quest to find a house and job by interacting with a cast of characters. Through these social interactions, the participants formed opinions about how much power each character held, and how kindly they felt toward him or her. These judgments put each character in a position on a “social space” map. Activity in the hippocampus was related to this social mapmaking, Tavares and colleagues found.
It turns out that this social map depends on the traits of the person who is drawing it, says Tavares, of Icahn School of Medicine at Mount Sinai in New York City. People with more social anxiety tended to give more power to characters they interacted with. What’s more, these people’s social space maps were smaller overall, suggesting that they explored social space less, Tavares says. Tying these behavioral traits to the hippocampus may lead to a greater understanding of social behavior — and how this social mapping may go awry in psychiatric conditions, Tavares said.

The work emphasizes that the hippocampus is not just a mapper of space, Tavares says. Instead, it is a mapper of relationships. “It’s relational learning,” she says. “It’s everything in perspective.”

Other research, discussed at a meeting in February, revealed a role for the hippocampus in building a very different sort of map — a map of sounds. Stationary rats were trained to “move” through a soundscape of different tones, pushing a joystick to change the sounds to reach the sweet spot — the target tone. As the rats navigated this auditory world, nerve cells in their hippocampus were active in a way that formed a map, Princeton University neuroscientist Dmitriy Aronov reported in Salt Lake City at the annual Computational and Systems Neuroscience meeting.

Cells in the hippocampus can also map time, keeping count as seconds tick by, Eichenbaum has found (SN: 12/12/15, p. 12). All of these types of information are quite different, but Eichenbaum argues that they can all be thought of as memories — another mental arena in which the hippocampus plays an important role. Organizing these memories into a sensible structure may be the big-picture job description of the hippocampus, he says. “What’s being tapped in all of these studies is that we are looking at a framework, whether it’s a physical spatial framework, a social space framework, a pitch framework, or a time framework,” Eichenbaum says.

Ocean outlook
Earth’s oceans are a hot mess. They absorb heat at twice the rate that they did nearly 20 years ago, Thomas Sumner reported in “Ocean heating doubles” (SN: 2/20/16, p. 18). Meanwhile, phytoplankton release more heat during photosynthesis than previously thought, Chris Samoray reported in “Ocean flora flunk photosynthesis test” (SN: 2/20/16, p. 12). And the trillions of plastic particles littering the oceans are creating new habitats for microbes with unknown consequences, Samoray wrote in “Floating fortress of microbes” (SN: 2/20/16, p. 20).
Anna Carter wondered if these findings are connected. “Is it possible that phytoplankton are contributing to ocean warming?” Carter asked. “How might the organisms now collecting on all the plastic in the ocean be related?”

Heat produced by phytoplankton doesn’t have a large impact on ocean temperature, says Sumner. “The phytoplankton are catching sunlight that otherwise could warm the water,” he wrote. “Another thing to keep in mind is that the oceans are colossal. At its deepest, the Pacific Ocean is about as deep as the cruising altitude at which most commercial airliners fly. Phytoplankton live in the top sliver of the water column, so any effect they have will be minuscule compared with the size of the ocean.” As for plastic-dwelling microbes, there is still so much to discover, Samoray says. Their contribution to ocean warming is currently unknown.

Ants on the move
Florida harvester ants may be the Frank Lloyd Wrights of the animal kingdom. They construct intricate and mysterious nests, Susan Milius reported in “Restless architects we don’t understand” (SN: 2/20/16, p. 4). Researchers investigated why ants frequently build and abandon elaborate nests, and scatter charcoal around nest openings.

Readers had their own ideas about the unusual behavior. “[Charcoal] is an effective absorber of organics. Is it possibly used for absorbing their scent as a protective measure against predators?” Mark Ayers asked.

Walter Tschinkel, the Florida State University scientist featured in the story, says that the scorched plant matter ants use may not be as effective for these purposes as commercial charcoal. Field tests found no sign that charcoal would deter attacks by other ants.

Reader Joe De Vita speculated that colonies abandon their nests because of waste buildup. Tschinkel notes that this hypothesis has yet to be tested. “Digging up the vacated nest often reveals chambers with matted, blackened floors, presumably from fungus and other microorganisms, but whether this condition has any negative (or for that matter, positive) effects on harvester ants is unknown,” he says. An experiment to test this hypothesis is possible, but “ain’t all that easy. Still, stay tuned.”

Milk for spills
Researchers have created a fibrous membrane made from milk proteins and carbon that could filter toxic heavy metals from severely polluted waters, Sarah Schwartz reported in “Altered milk protein cleans up pollution” (SN: 2/20/16, p. 14). In lab tests, the membrane removed over 99.9 percent of lead from a contaminated solution.

“It is a very exciting method,” wrote Janece Von Allmen. “Has anyone thought to test this method in the real polluted waters of Flint, Michigan?”

The filters are still in an early stage of design, Schwartz says. The membranes work in the laboratory to capture heavy metals and radioactive particles, but testing in the real world is a must. “Bodies of contaminated water are most likely chemically different from lab-made lead solutions and could change the membrane’s performance,” she says.

Whether or not these membranes would work in the Flint River is unclear because the river is not the original source of lead. The toxic heavy metal accumulates as the water passes through corroding pipes. The good news is the prototype shows signs of being efficient and is relatively cheap to produce.

In narrow blood vessels, tumor cells go marching one by one.

By unfolding into a cellular chain, clusters of cancer cells can slide through capillary tubes less than 10 micrometers wide, Sam Au of Harvard Medical School and colleagues report April 18 in the Proceedings of the National Academy of Sciences. The cells pass through the tubes in single file, each squeezing into an oblong shape and clinging to a neighbor or two. After arriving in roomier quarters, the cells regroup into round clumps, the scientists report.
Clumps of cancer cells that break off tumors and travel through the bloodstream to new sites in the body are known to spread cancer more efficiently than single cells. Many scientists believed, though, that hefty cell clusters were unable to squeeze through the body’s narrowest blood vessels.

Experiments showed that human breast and prostate cancer cells used this single-file strategy to travel through lab-made tubes, human cell‒lined tubes and the blood vessels of live zebrafish. These results could offer insights into ways to foil cancer’s spread.

Fountains of gas from a handful of remote galaxies all seem to be pointing in roughly the same direction, a new study reports. If the result holds up, it puts a new twist on how galaxies and black holes arise from the larger cosmic web, though some researchers worry that the alignment might just be a chance occurrence.

Out of a group of 64 galaxies that are blasting out radio waves, about a dozen are spewing jets of gas that are roughly aligned with one another, astronomers report in the June 11 Monthly Notices of the Royal Astronomical Society Letters. The galactic geysers are powered by supermassive black holes whose magnetic fields launch some infalling debris into intergalactic space. If the geysers are aligned, that means the black holes are all spinning in the same direction. And that means these galaxies, which are spread over roughly a hundred million light-years, might all have been influenced by the larger scaffolding from which they formed.
“Naively we expect that shouldn’t happen,” says Ryan Hickox, an astrophysicist at Dartmouth College who was not involved with this study. Black holes, even supermassive ones, are minuscule compared with filaments of galaxies that can span hundreds of millions of light-years. These filaments are the threads along which most matter in the universe congregates, branching through space like a cosmic spider web. Though galaxies live there, they are thought to form and develop independently of what the filaments are doing. A twisting filament should have no influence over what’s happening around one of its resident black holes.

And yet that’s the explanation favored by study lead Russ Taylor, an astrophysicist at the University of Cape Town in South Africa. “What we’re seeing is the result of a very large region in the early universe spinning coherently in the same direction,” he says. If that’s true, it adds a “new wrinkle to explain how large-scale structure formed.”

Taylor and colleagues found the apparent alignment while probing a patch of sky in the constellation Draco with the Giant Metrewave Radio Telescope in India. They don’t know the distances to the galaxies, but all seem to sit near a galactic supercluster whose light takes about 7.4 billion years to reach Earth — just over half the age of the universe.

Other researchers using different techniques have previously reported similar alignments among another set of galaxies (SN: 12/27/14, p. 6). Both studies, though, relied on a small number of galaxies, which means the alignment might not be statistically significant.

“If an alignment like this exists, it’s very interesting,” says astrophysicist Michael DiPompeo, also at Dartmouth. “But I’m not super convinced that it’s really there.” While Taylor and colleagues argue that the alignment is not a statistical fluke, DiPompeo did his own calculations that suggest otherwise. He simulated observations of 64 randomly oriented galaxy jets — the computer equivalent of repeatedly dropping a bunch of toothpicks on a table and noting where each was pointed. “I could pretty regularly get patterns that look like this,” he says.
It’s also hard to imagine how such an alignment, if it was present as the galaxies formed, could persist for billion of years, he says. “It’s not like [galaxies] form in the early universe and then just sit there blasting these jets.” Galaxies grow by colliding with other galaxies, which can change how the galaxies and their central black holes rotate.

Both DiPompeo and Hickox say it’s worth probing other galactic gatherings, though, before dismissing these alignments as a coincidence. If similar orientations appear in many galaxy clusters, then the researchers could be on to something. Hickox would also like to see distances to these galaxies. If it turns out the galaxies sit at wildly varying distances from Earth, he says, then the alignment is less likely to be real.

Taylor hopes to do just that. Colleagues are planning observations at other telescopes that will let them determine how far away these galaxies are. And Taylor is gearing up for a more thorough investigation over a much larger patch of sky with a new radio observatory in South Africa called MeerKAT, which should be ready for operation later this year.

In a bit of Irish luck, archaeologists have found evidence of the Emerald Isle’s earliest known humans. A brown bear’s kneecap excavated in 1903, featuring stone tool incisions, pushes back the date that humans set foot in Ireland by as many as 2,500 years.

Radiocarbon dating at two independent labs places the bone’s age between about 12,800 and 12,600 years old, say Marion Dowd of the Institute of Technology, Sligo in Ireland and Ruth Carden of the National Museum of Ireland in Dublin. Melting glaciers and milder temperatures in northwestern Europe at that time made it easier for humans to reach Ireland by boat to hunt game, at least for several weeks at a time, the researchers propose in the May 1 Quaternary Science Reviews.
Until now, the oldest signs of people on Ireland came from a hunter-gatherer camp dating to about 10,290 years ago.

Carden discovered the brown bear’s kneecap while studying bones that had been packed away in boxes in the 1920s, after the bones’ 1903 discovery at Ireland’s Alice and Gwendoline Cave.