How hagfish survive shark attacks


This video says about itself:

Hagfish predatory behaviour and slime defence mechanism

26 October 2011

Hagfishes (Myxinidae) are a family of jawless marine pre-vertebrates. Those video images taken in New Zealand revealed that hagfishes are able to choke their would-be predators with gill-clogging slime.It also shows that hagfishes are actively preying on other fish in New Zealand waters.

The video is part of a scientific paper describing this newly discovered behaviour which can be downloaded online.

From Science News:

Unusually loose skin helps hagfish survive shark attacks

Slip-sliding outer covering also aids in Houdini escapes

By Susan Milius

6:26pm, January 6, 2017

NEW ORLEANS, La. – Skin that mostly hangs loose around hagfishes proves handy for living through a shark attack or wriggling through a crevice.

The skin on hagfishes’ long, sausage-style bodies is attached in a line down the center of their backs and in flexible connections where glands release slime, explained Douglas Fudge of Chapman University in Orange, Calif. This floating skin easily slip-slides in various directions. A shark tooth can puncture the skin but not stab into the muscle below. And a shark attack is just one of the crises when loose skin can help, Fudge reported January 5 at the annual meeting of the Society for Integrative and Comparative Biology.

Hagfishes can fend off an attacking shark by quick-releasing a cloud of slime. Yet video of such events shows that a shark can land a bite before getting slimed. To figure out how hagfishes might survive such wounds, Fudge and colleagues used an indoor guillotine to drop a large mako shark tooth into hagfish carcasses. With the skin in its naturally loose state, the tooth readily punched through skin but slipped away from stabbing into the body of either the Atlantic (Myxine glutinosa) or Pacific (Eptatretus stoutii) hagfish species.

But when the researchers glued the skin firmly to the hagfish muscle so the skin couldn’t slip, the tooth typically plunged into inner tissue. For comparison, the researchers tested lampreys, which are similarly tube-shaped but with skin well-fastened to their innards. When the guillotine dropped on them, the tooth often stabbed directly into flesh.

The finding makes sense to Theodore Uyeno of Valdosta State University in Georgia, whose laboratory work suggests how loose skin might work in minimizing damage from shark bites. He and colleagues have tested how hard it is to puncture swatches of skin from both the Atlantic and Pacific species. As is true for many other materials, punching through a swatch of hagfish skin held taut didn’t take as long as punching through skin patches allowed to go slack, he said in a January 5 presentation at the meeting. Even a slight delay when a sharp point bears down on baggy skin might allow the hagfish to start dodging and sliming.

But Michelle Graham, who studies locomotion in flying snakes at Virginia Tech, wondered if puncture wounds would be a drawback to such a defense. A hagfish that avoids a deep stab could still lose blood from the skin puncture. That’s true, said Fudge, but the loss doesn’t seem to be great. Hagfish have unusually low blood pressure, and video of real attacks doesn’t show great gushes.

Hagfish blood also plays a part in another benefit of loose skin — an unusual ability to wiggle through cracks, Fudge reported in a second talk at the meeting. One of his students built an adjustable crevice and found that both Atlantic and Pacific hagfishes can contort themselves through slits only half as wide as their original body diameter. Videos show skin bulging out to the rear as the strong pinch of the opening forces blood backward.

The cavity just under a hagfish’s skin can hold roughly a third of its blood. Forcing that reservoir backward can help shrink the body diameter. Fortunately the inner body tapers at the end, Fudge said. So as blood builds up, “they don’t explode.”

Animals and physics, new book


This video says about itself:

Glamorous Indian Peacock

Discover the mating ritual of the Indian Peafowl!

From Science News:

‘Furry Logic’ showcases how animals exploit physics

Book chronicles use of light, magnetism and other phenomena

By Sid Perkins

8:00am, January 7, 2017

Furry Logic
Matin Durrani and Liz Kalaugher
Bloomsbury, $27

Warning: Furry Logic is not, as the title might suggest, a detailed exploration of mammals’ reasoning skills. Instead, it’s a fun, informative chronicle of how myriad animals take advantage of the laws of physics.

Science writers Matin Durrani and Liz Kalaugher cite a trove of recent (and often surprising) research findings. They draw on their backgrounds — Durrani is a physicist, Kalaugher a materials scientist — to explain how animals exploit sound, light, electricity and magnetism, among other things, in pursuit of food, sex and survival. These creatures don’t consciously use physics the way that humans design and use tools, of course, but they are evolutionary marvels nonetheless.

Peacocks, for example, produce low-frequency sounds while shimmying their tail feathers (SN Online: 04/27/16). The birds use these sounds — and not just the sight of those colorful plumes — to impress females and fend off competing males. At the other end of the sonic spectrum, some bats use stealth echolocation to track down their preferred prey. Moths targeted by these bats have sensors that can pick up these ultrasonic calls, but the bats squeak so softly that a moth can’t hear its stalker until it is less than a half-second’s flight away.

Durrani and Kalaugher let readers know when the science isn’t settled. Researchers aren’t quite sure how peahens pick up males’ infrasonic signals, for example. Scientists also haven’t figured out how the archerfish spits so precisely (SN: 10/4/14, p. 8), knocking prey off low-hanging branches above the water as often as 94 percent of the time. The submerged fish must somehow gauge the angle at which light bends as it enters the water and then accurately compensate for refraction while spewing a stream of water. Amazingly, this feat may be innate rather than learned via trial and error.

Readers need not understand the intricacies of polarized light, Earth’s magnetic field or surface tension to enjoy Furry Logic. Nor is this book an exhaustive account of the characteristics and behavior of every animal that uses such phenomena in interesting ways. There should be plenty of material for a sequel to this fascinating book.

Carnivorous plants, new research


This video says about itself:

14 January 2014

Discover one of the most unique hunters of the plant kingdom, and witness how the cobra lily (Darlingtonia californica) uses deception and patience to trick unsuspecting insect prey into its highly specialized pitcher traps.

From Science News in the USA:

Meat-eating pitcher plants raise deathtraps to an art

Green carnivores hunt with scum and sweets

By Susan Milius

7:00am, January 6, 2017

Tricking some bug into drowning takes finesse, especially for a hungry meat eater with no brain, eyes or moving parts. Yet California pitcher plants are very good at it.

Growing where deposits of the mineral serpentine would kill most other plants, Darlingtonia californica survives in low-nutrient soil by being “very meat dependent,” says David Armitage of the University of Notre Dame in Indiana. Leaves he has tested get up to 95 percent of their nitrogen from wasps, beetles, ants or other insects that become trapped inside the snake-curved hollow leaves.

The leaves don’t collect rainwater because a green dome covers the top. Instead, they suck moisture up through the roots and (somehow) release it into the hollow trap. “People have been doing weird experiments where they feed [a plant] meat and milk and other things to try to trigger it to release water,” Armitage says. Experiments tempting the green carnivore with cheese, beef broth, egg whites and so on suggest there’s some sort of chemical cue.

However the water enters the leaf pool, it starts out clear. As insects drown, the liquid darkens to a murky brown or red and “smells just horrible,” he says. The soupiness comes from bacteria, which help doom prey by lowering the surface tension of the drowning pool, Armitage reports in the November Biology Letters. Ants or other small insects sink below the surface immediately instead of floating at the top.

But first, pitchers lure victims to the pool by repurposing an old plant ploy: free nectar. It’s “highly nitrogen-rich and full of sugars, so it’s delicious — I’ve tasted it,” Armitage says. Pitcher plants sprout blooms, but the trap nectar doesn’t come from the drooping flowers. A roll of tissue near the pitcher mouth oozes the treat.

That nectar-heavy roll curves onto what’s called the fishtail appendage. Mature plants (2 years or older) grow this forked tissue like a moustache at the pitcher mouth. Biologists for more than a century have presumed that this big, red-veined, lickable prong worked as an insect lure. Armitage, however, tested the idea and says it may be wrong.

Clipping fishtails off individual leaves, or even off all the leaves in a small patch, did nothing to shrink the catch compared with fully mustachioed leaves, he reported in the American Journal of Botany in April 2016. The only thing fishtails lure, for the time being at least, are puzzled botanists.

Acorn worms, new research


This video says about itself:

29 November 2016

What if humans could regrow an amputated arm or leg, or completely restore nervous system function after a spinal cord injury?

A new study of one of our closest invertebrate relatives, the acorn worm, reveals that this feat might one day be possible. Acorn worms burrow in the sand around coral reefs, but their ancestral relationship to chordates means they have a genetic makeup and body plan surprisingly similar to ours.

Read more here.

From Science News in the USA:

These acorn worms have a head for swimming

Putting off trunk development may make catching prey easier, researchers say

By Emily DeMarco

10:00am, January 3, 2017

Certain marine worms spend their larval phase as little more than a tiny, transparent “swimming head.” A new study explores the genes involved in that headfirst approach to life.

A mud flat in Morro Bay, Calif., is the only known place where this one species of acorn worm, Schizocardium californicum, is found. After digging up the creatures, Paul Gonzalez, an evolutionary developmental biologist at Stanford University, raised hordes of the larvae at Stanford’s Hopkins Marine Station in Pacific Grove, Calif.

Because a larva and an adult worm look so different, scientists wondered if the same genes and molecular machinery were involved in both phases of development. To find out, Gonzalez and colleagues analyzed the worm’s genetic blueprint during each phase, they report online December 8 in Current Biology.

Genes linked to trunk development were switched off during the larval phase until just before metamorphosis. Instead, most of the genes switched on were associated with head development, Gonzalez says.

The larvae hatch from eggs laid on the mud. When tides flood the area, the squishy, gel-filled animals use hairlike cilia to swim upwards to devour bits of algae. “They’re feeding machines,” Gonzalez says. He speculates that being balloon-shaped noggins, rather than wriggling noodles, may help the organisms float and feed more efficiently.

After about two months of gorging at the algae buffet, the larvae, which grow to roughly 2 millimeters across, transform and sink back into the muck. There, they eventually grow a body that can stretch up to about 40 centimeters.

Earliest nightshade plant fossil discovered


This video is called Biology: Morphology of Flowering Plants: Solanaceae.

From Science News:

Tomatillo fossil is oldest nightshade plant

Pocketed berry is millions of years older than earlier estimates

By Meghan Rosen

2:14pm, January 5, 2017

Two tiny tomatillo fossils have kicked the origin of nightshade plants back to the age of dinosaurs.

The fossils, pressed into 52-million-year-old rock, suggest that the nightshade family originated millions of years earlier than scientists had suspected, researchers report in the Jan. 6 Science.

Nightshades include roughly 2,500 species of plants, from tomatoes to eggplants to tobacco. Previous estimates had dated the family to some 30 to 51 million years ago. And scientists had suggested that tomatillos, specifically, arose even more recently, around 10 million years ago.

Paleontologist Peter Wilf and colleagues have nixed that timeline. They uncovered the roughly 2-centimeter-tall fossils from an ancient lake in what is now [Argentinian] Patagonia. Each fossil preserves the delicate, tissue-paper-like sheath that typically covers a tomatillo’s central berry, like a candle inside a paper lantern. In one fossil, evidence of a berry (now turned to coal) still remains.

“This is like an impossible fossil,” says Wilf, of Pennsylvania State University in University Park. “That you could preserve something this delicate — this little papery structure. It’s unheard of.”

The outer structures may keep tomatillo berries dry — and afloat. “You’ve got an umbrella and a life raft,” Wilf says. And it’s built right in.

The fossils represent a new species of tomatillo, called Physalis infinemundi, Wilf and colleagues at Cornell University and the Paleontological Museum Egidio Feruglio in Patagonia report. Infinemundi is Latin for “at the end of the world.”

Fifty-two million years ago puts these tomatillos deep in the southern hemisphere during the final days of the supercontinent Gondwana, before Antarctica split from Australia and the southern tip of South America.

Creationists and dinosaurs in the USA


This 2008 video from the USA has music from the Flintstones. It is about Sarah Palin, 2008 Republican party candidate for vice president, Donald Trump supporter and creationist, believing that dinosaurs and humans lived at the same time.

By Ed Mazza in the USA:

Creationist Ken Ham Gets Into Weirdest Twitter Fight With Washington Post Over Dinosaurs

Ham’s Noah’s Ark Encounter depicts dinosaurs living in cages.

01/02/2017 03:43 am ET

Creationist Ken Ham is steaming mad over a Washington Post article that claims his giant Noah’s Ark attraction teaches tourists that dinosaurs died in the biblical flood.

Ham, who believes the Earth is about 6,000 years old, fired off several additional tweets directed at the Post over the story.

Indeed, the Ark Encounter doesn’t claim all dinos died out during the flood. Rather, it features dinosaurs living in cages like the other animals.

His organization has said most dinosaurs died in the flood, which it claims took place 4,300 years ago.

“Those descended from the ones which got off the Ark eventually succumbed to the same sorts of pressures which cause extinction in animal populations today,” a 2011 blogpost said.

Scientists agree almost universally that dinosaurs were wiped out 65 million years ago, although researchers continue to study the specific causes. The American Museum of Natural History in New York notes that a comet or asteroid strike along with “massive volcanic eruptions and changing sea levels” all may have played a role.

Beefsteak polypore, 2017 Fungus of the Year


This video is about the beefsteak polypore.

The Dutch Mycological Society has named the beefsteak polypore (or ox tongue) as its 2017 Fungus of the Year.

This edible fungus lives mainly on English oak and related Quercus trees.