OMG science
fromwww.scientificamerican.com
1 day agoThe wild science of octopus sex
Male octopuses use a specialized arm to sense female hormones for mating, compensating for the lack of vision during reproduction.
When light shines through water, colors with longer wavelengths are absorbed by the water, with the longest wavelengths absorbed first. Blue and violet have the shortest wavelengths of visible light, so they are able to penetrate the deepest.
During major floods, thousands of tiny fish convene at Luvilombo Falls in the upper Congo River Basin to undertake a peculiar vertical migration, described for the first time today in Scientific Reports.
We think that in this early deuterostome, the median eye contained both ciliary and rhabdomeric cells. As a result, both cellular lineages were incorporated into a single, ancient, cyclopean eye, which later evolved into the vertebrate eyes.
The bodies of the crabs displayed male reproductive structures, while other parts showcased female features, including gonopores, said K.S. Anoop Das.
In a recent study published in the zoology journal Crustaceana, scientists working in Silent Valley National Park reported a new variety of the crab that exhibits both male and female traits. Our new crab friends, of the species Vela carli, are freshwater dwellers that hang out in the streams of the Western Ghats in India.
I've wanted to be an ocean swimmer ever since I moved to Sydney. The idea of getting out past the waves and braving the elements excited me. I would tell anyone who would listen: Once I live closer to the beach, I'm going to be out there. Just you wait. I've lived walking distance to the beach for more than a year now. During this time, I've read a lot about ocean swimming: how swimmers overcame challenges or life-altering moments.
1 Rodney King beating. 2 Boreal forest (taiga). 3 Named storm in the UK. 4 Dr Faustus (Marlowe play). 5 Floella Benjamin. 6 Gentlemen v Players. 7 RNLI. 8 Classical music. 9 Plots against Elizabeth I. 10 Ways of having your steak in France. 11 Animals that can walk on water. 12 Birth states of US presidents. 13 Scales used to measure natural phenomena: tornadoes; earthquakes; hurricanes; hazard from near-Earth objects.
'Orcas are psychos,' quipped a close friend recently. He wasn't joking, nor was he ill-informed. In fact, he is probably the world's leading historian of whales and people. He had just watched a BBC Earth clip, narrated by David Attenborough, in which three killer whales separate a male humpback calf from his mother in the waters of Western Australia. The video's closing footage, with two of the orcas escorting the naive youngster to his imminent death, resembles nothing so much as a kidnapping:
We've documented sightings of glass squids to better understand the remarkable transformations they undergo from hatchlings to adults. This new observation, captured in ultra high-resolution 4K, allowed us to zoom in on a juvenile likely no bigger than a baby carrot and reveal more details than we have been able to see before.
Bumps or grooves of a range of sizes - from the sub-micrometre scales of visible-light wavelengths up to millimetres - affect how a surface scatters light. This can make a material more or less dull, or change its colour when observed from different angles. Molluscs, such as octopuses and cuttlefish, use tiny muscles embedded in their skin to produce these effects for camouflage or communication.
The animals do, however, have neuronsnerve cells that appear interconnected throughout their body. And now a new study shows that how these animals sleep is surprisingly similar to humans, suggesting that sleep may have evolved before even the most primitive brains. The findings, published on Tuesday in Nature Communications, also help answer one of science's prevailing mysteries: Why do animals sleep?
Neither jellyfish nor sea anemones have brains. But these animals sleep in ways strikingly similar to humans, according to a study published today in Nature Communications. The findings bolster a theory that sleep evolved, at least in part, to protect the DNA in individual nerve cells, helping to repair damage that builds up while animals are awake.
Some deep-sea fish may be able to see light in a different way from most other vertebrates, according to a new study. The fish, found in the Red Sea, have what the scientists behind the new study describe as hybrid photoreceptorslight-sensing cells in the retina that combine elements of two distinct kinds of photoreceptors, cones and rods. In human retinas, cone cells enable us to see in bright environments, detecting color and fine detail,
Which animals came first? For more than a century, most evidence suggested that sponges, immobile filter-feeders that lack muscles, neurons and other specialized tissues, were the first animal lineages to emerge. Then, in 2008, a genomic study pointed to a head-scratching rival: dazzling, translucent predators called comb jellies, or ctenophores, with nerves, muscles and other sophisticated features. That single study ignited a debate that has raged for nearly 20 years, sparking fierce arguments about how complexity evolved in animals.
Recently, two unexpected examples by a wild wolf and a domesticated cow named Veronika attracted global attention and once again opened the door for experts and others to weigh in on the question, "Are these really examples of tooling?" Many people are eager to know more about the nitty-gritty details of tooling, so I am thrilled that Dr. Benjamin Beck, an expert in this area, could answer a few questions about this fascinating behavior.
But as he swept his flashlight through the dark waters, something unexpected emerged. Inching through the beam of light, an alien creature crawled across the surface of the sand, resembling an inch-long cluster of ghostly leaves fringed with silvery filigree and capped with a pair of antennae-like stalks. It immediately caught my eye, said Gosliner, Invertebrate Zoology Curator for the California Academy of Sciences. I've been diving there for 30 years and this one immediately struck me as different.
Wooden objects carrying the marks of carving and use could be the oldest wooden tools ever found. Researchers dated the artefacts, found in what is now Greece, to 430,000 years ago - and suggest they might have been made by early Neanderthals or their ancestors, Homo heidelbergensis. A separate study describes 480,000-old flint-knapping tools made from antler and elephant bone, from what is now the United Kingdom.
It looked like the silvery blade of a knife. Peering through his goggles, diver Ted Judah had laid eyes on a deep-sea creature rarely encountered by humans. He and wife Linda were diving off McAbee Beach in Monterey County in late December when, near the surface, he spotted the undulating thing. It was some kind of ribbon fish, he wrote in a post on the Facebook group Monterey County Dive Reports. Kevin Lewand solved the mystery.
An elephant's trunk is a marvelous thing, flexible enough to bend and stretch as it forages for food, but also stiff enough to grasp and maneuver even delicate objects like peanuts or a tortilla chip. That's because the trunk is highly sensitive when it comes to sensing touch. Scientists have determined that the whiskers lining the trunk are crucial for that sensitivity thanks to their unique structure, amounting to a kind of innate "material intelligence, according to a new paper published in the journal Science.
The lava heron also has a much thicker bill than other closely related herons - an adaptation linked to feeding among sharp volcanic rocks and hard-shelled prey. "What we learned was something that hadn't been reported before," Mendales said. The discovery underscores how much remains unknown, even in iconic places like the Galápagos, said John Dumbacher, the Academy's curator of birds and mammals and Mendales' thesis adviser.
The mirror spider can rapidly shift a patchwork of minuscule reflective plates underneath its abdomen's outer surface, altering the pattern of mirrorlike flashes. This uncommon display comes from common building blocks: Similar tilelike arrangements of plates and soft joints appear throughout the tree of life, from turtle shells to tropical fruit peels. Researchers have now compiled 100 examples of this pattern across animals, plants, microbes and viruses, which they describe in PNAS Nexus.
A simple example of space-tuned cells is HD cells, which persistently fire when animals are facing a particular direction8. Because the head direction of an animal is typically not directly provided to the sensory system, HD cells need to integrate the history of rotational movements that animals make, a process called angular path integration. As a simple, yet biophysically plausible mechanism to implement angular path integration, a class of dynamical models called ring attractors has been proposed9.