Tag: biology

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    Mapping the Oceans With Seals

    Elephant seals are harbingers — canaries in the coal mine — for climate change. A long-running experiment tracks northern elephant seal populations using a combination of sensor tags and field measurements. With the miniaturization of sensors, a tagged seal can provide a wealth of data for scientists: foraging paths, temperature and salinity data, behavioral patterns, ecological data, and even information on the species around the seal. This video delves into this treasure trove, explaining how and what we’re learning from this species, especially as they navigate our changing climate. (Video and image credit: Science)

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  • Swimming Like a Ray

    Swimming Like a Ray

    Manta rays are amazing and efficient swimmers — a necessity for any large animal that survives on tiny plankton. Researchers have built a new soft robot inspired by swimming mantas. Like its biological inspiration, the robot flaps its pectoral fins much as bird flaps its wings; this motion creates vortices that push water behind the robot, propelling it forward. For a downstroke, air inflates the robot’s body cavity, pushing the fins downward. When that air is released, its fins snap back up. With this simple and energy efficient stroke, researchers are able to control the robot’s swimming speed and depth, allowing it to maneuver around obstacles. Flapping faster helps the robot surface, and slower flapping allows it to sink. (Living manta rays also sink if they slow down.) Check out the robot in action below. (Image credit: J. Lanoy; video and research credit: H. Qing et al.; via Ars Technica)

  • Strata of Starlings

    Strata of Starlings

    Starlings come together in groups of up to thousands of birds for the protection of numbers. These flocks form spellbinding, undulating masses known as murmurations, where the movement of individual starlings sends waves spreading from neighbor to neighbor through the group. One bird’s effort to dodge a hawk triggers a giant, spreading ripple in the flock.

    To capture the flowing nature of the murmuration, photographer and scientist Kathryn Cooper layers multiple images of the starlings atop one another. The birds themselves become pathlines marking the murmuration’s motion. The final images are surprisingly varied in form. Some flocks resemble a downpour of rain; others the dangling branches of a tree. (Image credit: K. Cooper; via Colossal)

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  • “Flowing Kelp”

    “Flowing Kelp”

    This CUPOTY-shortlisted photo by Sigfrido Zimmerman shows giant kelp drifting in the current. At the base of each blade is an inflated bladder that helps keep the algae buoyant. The blades themselves are furrowed on their surface, with patterns reminiscent of sand ripples. Though giant kelp can grow to as large as 60 meters, the species lives in constant flux, pushed and pulled by the currents that run along its length. (Image credit: S. Zimmerman/CUPOTY; via Colossal)

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  • Holding Steady

    Holding Steady

    Before a mammalian cell divides, the spindle — a protein structure — divides the cell’s genetic material in two. As it does, the cytoplasm inside the cell forms a toroidal flow (below, left). Researchers wondered how the spindle manages to stay in place with this flow; the spindle sits just where the flow diverges, a spot that seems ripe for unstable shifts in position. But, contrary to expectations, their analysis showed that — although a smaller spindle would be unstable in that spot — the protein spindle is large enough that its size distorts the cell’s flow and creates a pressure that moves it back into place if it shifts. (Image credit: top – ColiN00B, illustration – W. Liao and E. Lauga; research credit: W. Liao and E. Lauga; via APS Physics)

    Left: illustration of the toroidal flow near the spindle (purple) in a cell. Right: schematic of flow near the spindle's fixed point.
    Left: illustration of the toroidal flow near the spindle (purple) in a cell. Right: schematic of flow near the spindle’s fixed point.
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    Tar Pit, Sweet Tar Pit

    The La Brea Tar Pits have delivered countless creatures to their doom over tens of thousands of years. But the sticky quagmire of the pits’ natural asphalt is a comfy home to at least one animal: the petroleum fly. The fly’s maggots secrete a lipophobic — in other words, oil-repelling — fluid that allows them to move freely through the viscous black tar. That freedom means they can take full advantage of the asphalt’s trapping power by consuming a smorgasbord of stuck victims. Any asphalt the maggots swallow just passes harmlessly through them. As adults, only their feet are asphalt-resistant, but the petroleum fly still spends most its time hanging out in the pit, seeding the next generation. (Video and image credit: Deep Look)

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  • Dry Plants Warn Away Moths

    Dry Plants Warn Away Moths

    Drought-stressed plants let out ultrasonic distress cries that moths use to avoid plants that can’t support their offspring. In ideal circumstances, a plant is constantly pulling water up from the soil, through its roots, and out its leaves through transpiration. This creates a strong negative pressure — varying from 2 to 17 atmospheres’ worth — inside the plant’s xylem. If there’s not enough water to keep the plant’s inner flow going, cavitation occurs — essentially a tiny vacuum bubble opens in the xylem. That cavitation isn’t silent; it creates a click at ultrasonic frequencies above human hearing. But just because we don’t hear it doesn’t mean that sound goes unheard.

    In fact, recent research suggests that, not only do moths hear the plant’s cavitation cries, female moths will avoid laying eggs on a healthy plant that sounds like it’s cavitating. Evolutionarily, this makes sense. Hatchlings rely on their birth plant for food and habitat; if an adult moth picks a dying, drought-stressed plant, its offspring won’t survive. It pays to be sensitive to the plant’s signs of distress. (Image credit: Khalil; research credit: R. Seltzer et al.; via NYTimes)

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  • Inside the Squirting Cucumber

    Inside the Squirting Cucumber

    Though only 5 cm long, the squirting cucumber can spray its seeds up to 10 meters away. The little fruit does so through a clever combination of preparation and ballistic maneuvers. Ahead of launch, the plant actually moves water from the fruit into the stem; this reorients the cucumber so that its long axis sits close to 45 degrees. It also makes the stem thicker and stiffer.

    This high-speed video shows the explosive release of the squirting cucumber's seeds.
    This high-speed video shows the explosive release of the squirting cucumber’s seeds.

    When the burst happens, fruit spews out a jet of mucus that propels the seeds at up to 20 m/s. The initial seeds move the fastest — thanks to the fruit’s high-pressure reservoir — and fly the furthest. As the pressure drops, the jet slows and the fruit’s rotation sends the seeds higher, causing them to land closer to the original plant. With multiple fruits in different orientations, a single plant can spread its seeds in a fairly even ring around itself. (Research and image credit: F. Box et al.; via Gizmodo)

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  • Inside a Big Cat’s Roar

    Inside a Big Cat’s Roar

    The roars of big cats — tigers, lions, jaguars, and leopards — carry long distances. In part, this reflects the animals’ size: large lungs exhale lots of air through a large voice-box, whose vibrations resonate in a large throat. But size alone does not make the roar. Below are examples of two big cat voice-boxes. On the left is the nonroaring snow leopard; on the right is the voice-box of a roaring jaguar. The red boxes labeled “VF” mark each cat’s vocal folds. Nonroaring cats have triangular folds, while roaring ones have thick square or rectangular vocal folds. These rectangular folds are more aerodynamically efficient, allowing them to produce a wider range of output levels. They’re also more resilient to the intense forces of a roar, thanks to the cushioning effect of fat deposits inside them. If interested, you can learn more over at Physics Today. (Image credit: tiger – T. Myburgh, voice box – E. Walsh and J. McGee; research credit: E. Walsh and J. McGee)

    The vocal folds (VF) of nonroaring cats are triangular (left), whereas roaring cats have rectangular vocal folds (right).
    The vocal folds (VF) of nonroaring cats are triangular (left), whereas roaring cats have rectangular vocal folds (right).
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    Skydiving Salamanders

    The wandering salamander can spend its entire 20-year lifespan in the canopy of a coast redwood. When predators come calling, they have a special skill that helps them get away: skydiving. These little amphibians have no webbed appendages and no wings, but they’re some of the most skillful skydivers out there. By carefully repositioning its tail and feet, a wandering salamander controls its pitch, yaw, and roll. It’s not only able to orient itself as it falls; it can actually steer itself to a safe landing! Other salamander species, as seen in the video above, do not share this skill. Check out the full Deep Look video to see these incredible gliders in action. (Video and image credit: Deep Look; see also C. Brown)