FYFD

Tag: biology

  • How Frogs Block Unwanted Noise

    How Frogs Block Unwanted Noise

    In a crowded room, it can be hard to pick out the one conversation you want to hear. This so-called “cocktail party problem” is one animals have to contend with, too, when a noisy landscape can obscure the calls of potential mates. American green tree frogs have a clever solution to the problem: inflating their lungs to dampen out other frog species’ calls.

    This method works because frogs have a direct anatomical connection between their lungs and their eardrums. Researchers found that when these frogs inflate their lungs, there’s a pronounced drop in their sensitivity to sound in the 1.4 – 2.2 kHz frequency band. That frequency range falls between the green tree frog’s peak mating call frequencies, but it coincides with the frequencies of other frogs living in the same regions. So rather than using their lungs to make themselves louder, these clever amphibians use them to make other frogs quieter! (Image credit: B. Gratwicke; research credit: N. Lee et al.; via Physics Today)

  • Featured Video Play Icon

    When Squids Fly

    Some species of squid fly at speeds comparable to a motorboat for distances of 50 meters. The cephalopods get into the air the same way they swim underwater: by expelling a jet of water through the center of their body. Once aloft, the squids spread their tentacles to form a semi-rigid wing-like surface for lift. They can also use fins on their mantle as a canard for additional lift or control of their altitude. Researchers suspect the squids use flight as an escape mechanism to put distance between themselves and predators, but it could also be a low-energy migration strategy since a single pulse carries a squid farther in air than in water. (Video and image credit: TED-Ed)

  • Featured Video Play Icon

    Flamingo Filter-Feeding

    Flamingoes are strange and ungainly creatures, but their hooked bills make much more sense when you see them eating underwater. The birds are filter feeders, and they suck water, mud, and silt in through the front of their bills and pump it back out the sides. In between hairy structures called lamellae help them separate algae, brine shrimp and other food from the mix. Be sure to turn the sound up on the video so that you can hear the sound of flamingoes at work. (Image and video credit: San Diego Zoo; via Colossal)

  • Featured Video Play Icon

    “Columbia”

    “Columbia” is a music video illustrated with fluid dynamics, chemistry, and biology by the Beauty of Science team. It’s got everything from precipitation to crystallization, from infrared imagery of wakes to timelapses of growing molds. How many phenomena can you identify? (Video and image credit: Beauty of Science)

  • Loopy Networks and Bird Lungs

    Loopy Networks and Bird Lungs

    When mammals breathe, air flows back and forth inside our lungs. But in birds that inhale and exhale get transformed into one-directional flow inside their lungs. To figure out how, researchers built loopy networks of pipes that turn oscillating flow into unidirectional flow.

    The simplest structure that does this is shown above. The main loop is driven by a pump that oscillates back and forth. A second loop connects through two T-junctions, oriented at 90-degrees to one another. Watch the particles in each loop carefully. Those in the bottom loop move back and forth, driven by the oscillating pump. But the particles in the upper loop only move in one direction! The key to this, the researchers found, are vortices that form at the T-junctions (last image). When the flow in the main loop changes direction, it creates vortices that block flow along one arm of the T-junction, thereby isolating the upper loop. (Image credit: bird – A. Mckie, others – Q. Nguyen et al.; research credit: Q. Nguyen et al.; via APS Physics; submitted by Kam-Yung Soh)

  • Featured Video Play Icon

    The Unsinkable Pygmy Gecko

    The Brazilian pygmy gecko is a tiny inhabitant of the Amazon rainforest, growing to no longer than 24 mm. But these tiny lizards have some incredible superpowers when it comes to surviving the rainforest’s deluges. The gecko’s surface is superhydrophobic — water repellent — thanks to millions of tiny hairs that create air pockets between water and the gecko’s skin. This superhydrophobic surface, combined with the gecko’s tiny stature, allow it to sit atop water, supported entirely by surface tension. (Image and video credit: BBC Earth)

  • The Fluidity of Worm Blobs

    The Fluidity of Worm Blobs

    The aquatic blackworm forms blobs composed of thousands of individual worms for protection against evaporation, light, and heat. The worms braid themselves together (Image 1). Once a blob forms, it is extremely viscoelastic, displaying properties both solid and fluid in nature (Image 2).

    The worm blobs act like a collective; they bunch up to prevent evaporation that would desiccate the worms. Under intense light, the blob contracts (Image 3). The worms also prefer colder temperatures (again, to prevent evaporation) and will move toward the colder side of a temperature gradient. Under dim light, they’ll move individually, but in brighter light, the worms move collectively as a blob (Image 4).

    To do so, worms on the colder side of the blob pull toward the cold, whereas worms elsewhere in the blob wiggle (Image 5). Their wiggling helps lift the blob and reduce its friction so that the pulling worms can move the blob in the right direction. For more, check out this excellent thread by one of the authors. (Image and research credit: Y. Ozkan-Aydin et al.; via S. Bhamla; submitted by Maximilian S.)

  • How Wombats Make Stackable Feces

    How Wombats Make Stackable Feces

    Wombats are unique among the animal kingdom for their ability to produce cubic feces approximately the size and shape of dice. Researchers found that wombats accomplish this geometric feat thanks to the structure of their intestines, which have bands of differing stiffness that run the full length of their guts. When the intestines contract, the stiffer bands contract first, gradually shaping and sculpting the corners of the feces.

    The results have implications both for manufacturing soft materials and for human health. One of the early effects of colon cancer is a stiffening of portions of the intestine; that means that doctors may be able to use changes in the shape of a patient’s feces as a warning sign for diagnosis. (Image and research credit: P. Yang et al.; video credit: Royal Society of Chemistry; via Gizmodo)

  • Flexible Wings Aid Butterfly Flight

    Flexible Wings Aid Butterfly Flight

    Butterflies are some of the oddest flyers of the insect world, given the large size of their wings relative to their bodies. That could be a recipe for inefficient flight, but a new study shows that butterflies’ large flexible wings actually help them take off quickly.

    When lifting their wings, butterflies use an unusual clapping motion, with the leading edges of their wings coming together before the rest of the wings. This motion helps cup and direct air, creating most of the butterfly’s thrust, according to the researchers. The wings’ flexibility is key to this. Using artificial wings — both stiff and flexible — researchers found that the flexible wings generated 22% more useful impulse and were 28% more efficient. For a tiny flyer with frequent take-offs, that’s an enormous savings! (Image, video, and research credit: L. Johansson and P. Henningsson; via BBC; submitted by Kam-Yung Soh)

  • Sand Traps

    Sand Traps

    Antlion larvae catch prey by digging conical pits in sand. The steep walls of the trap are near the angle of repose, the largest angle a granular material can maintain before grains slide down. When a hapless ant wanders into the trap, the antlion throws sand from the center of the pit, triggering a sandslide that carries the ant downward. The act of flinging sand also helps the antlion maintain the pit, correcting any disruptions to the pit’s steep sides caused by its flailing prey. (Image and research credit: S. Büsse et al.; via Science)