Renewable Revolution

Environment => Wonders of Nature => Topic started by: AGelbert on January 04, 2015, 09:37:38 pm

Title: Special Sensory Perception
Post by: AGelbert on January 04, 2015, 09:37:38 pm

Songbirds fly coop long before tornadoes arrive in Tennessee

Thursday, December 18, 2014 

By Will Dunham

WASHINGTON (Reuters) – You might want to be careful about who you call a birdbrain. Some of our feathered friends exhibit powers of perception that put humans to shame.


Scientists said on Thursday that little songbirds known as golden-winged warblers fled their nesting grounds in Tennessee up to two days before the arrival of a fierce storm system that unleashed 84 tornadoes in southern U.S. states in April.  :o The researchers said the birds were apparently alerted to the danger by sounds at frequencies below the range of human hearing.  (

The storm killed 35 people, wrecked many homes, toppled trees and tossed vehicles around like toys, but the warblers were already long gone, flying up to 930 miles (1,500 km) to avoid the storm and reaching points as far away as Florida and Cuba, the researchers said.

Local weather conditions were normal when the birds took flight from their breeding ground in the Cumberland Mountains of eastern Tennessee, with no significant changes in factors like barometric pressure, temperature or wind speeds. And the storm, already spawning tornadoes, was still hundreds of miles away.

“This suggests that these birds can detect severe weather at great distances,” said wildlife biologist David Andersen of the U.S. Geological Survey and the University of Minnesota, one of the researchers in the study published in the journal Current Biology.

    “We hypothesize that the birds were detecting infrasound from tornadoes that were already occurring when the storm was still quite distant from our study site,” Andersen added.

Infrasound is below the normal limits of human hearing, but some animals can hear it.

The warblers came right back home after the storm passed, said fellow researcher Henry Streby, an ecologist from the University of California, Berkeley.

Male Golden-winged warbler

The researchers, who were already studying the migratory patterns of the warblers, tracked their evacuation using transmitters that had been placed on a small number of the birds.

Female Golden-winged warbler

Golden-winged warblers boast gray plumage marked by patches of yellow on the head and wings. They weigh about 0.30 ounces (9 grams) and have a wingspan of about 7.5 inches (19 cm).

The warblers spend winters in Central America and northern South America before migrating back to the Appalachian Mountain region of the southern United States and the Great Lakes region of the United States and Canada to breed.

(Writing by Will Dunham; Editing by Lisa Von Ahn)
Title: Re: Special Sensory Perception
Post by: AGelbert on March 24, 2017, 07:01:25 pm

Why woodpeckers don’t get headaches

Tibi Puiu March 23, 2017

Your typical woodpecker will bang its head against wood 20 times per second, accelerating 1,200 times more than gravity. In an average day, a woodpecker does this around 12,000 times. Despite the serious head banging, the woodpecker suffers no concussions or any kind of head injury. What’s this bird made of?  (

Credit: Pixabay

To get to the bottom of things, a team of researchers from Beijing and Hong Kong zoomed in on the woodpecker’s behaviour closer than anyone ever had. The birds were put inside a special chamber where two synchronous high-speed cameras recorded their pecking, and a force sensor measured the peck force.

The birds’ heads were also scanned with x-rays and an electron microscope to image the bone structure. Preserved woodpecker skulls were also placed in a material testing machine and crushed for science. This data was then used to build a 3D model of the birds’ heads which they can then smash in simulations, without hurting any actual live woodpeckers.

This battery of tests revealed the woodpecker’s skull is unsurprisingly very sturdy, unlike most birds whose skulls are fragile. It’s made out of extremely strong, yet compressible sponge-like bone. The spongy bone is unevenly distributed around the skull, being most concentrated in the forehead and the back of the skull. Additionally, the beak and skull are connected by an elastic tissue which helps cushion the blow.

Inside the skull, the woodpecker’s brain is also armoured. Unlike human brains which are floating about in a pool of cushioning cerebrospinal fluid, the woodpecker’s brain is very tightly enclosed in the skull, with little or no cerebrospinal fluid. This means its brain doesn’t move about very much and collision force is spread out evenly over a larger area. Probably, this is the most important feature that helps woodpeckers avoid concussions.

Scanning electron microscope images of the cranial bone and beak bone of the great spotted woodpecker and the lark Cranial bone of (a) woodpecker and (b) lark; beak of (c) woodpecker and (d) lark. Credit: PLOS ONE

The beak’s construction also helps a lot. The outer tissue of the upper beak is longer than the lower beak, but the bone structure of the lower beak is longer and stronger than the upper one. This overbite divests impact stress away from the brain and distributes it around the lower beak and bottom parts of the skull.

When you’re hammering out at over 1,000 g, you better wear some protection goggles. Woodpeckers have so-called nictitans — thick membranes beneath the lower lid of the eyes — which protect them from debris. The nictitans also act as seatbelts for the eyes, fixing them in place so the retina doesn’t tear and the eye doesn’t pop right out the skull for that matter.

The high-speed cameras also revealed the woodpeckers vary the paths of their pecks. As they constantly move their heads and beaks around, so fast that’s impossible to see with the naked eye, the birds essentially minimize the number of times in a row that the skull makes contact in the same point.

The researchers say 99.7 percent of the energy from striking a tree is absorbed by the woodpecker’s body, and only 0.3 percent actually impacts the brain. This energy mostly heats the brain, so to cope woodpeckers usually peck in short bursts with breaks in between. Researchers suppose these brief breaks serve to cool the woodpecker’s brain.

Findings appeared in the journal PLOS ONE.

Credit: McMaster University

Visit the link below to see the fascinating slow motion Gif of a Woodpecker pecking!  :o  (
Title: Re: Special Sensory Perception
Post by: AGelbert on April 16, 2017, 04:07:41 pm
Which Animals Use Starlight to Help with Navigation? (

It’s not rocket science, but a male dung beetle’s quest to navigate a newly-formed ball of dung in a straight line -- in order to avoid marauders who might steal the dung, and to get back to his mate as quickly as possible -- does require a certain amount of expertise in celestial navigation. In a 2013 study published in Current Biology, zoologist Marie Dacke’s team determined the dung beetle can find its way using only the Milky Way as a guide. Birds, seals, and humans have been known to use stars for navigation, but this was the first evidence that insects can do so, too.
Dung beetle Onthophagus nigriventris

Rollin', rollin', rollin':  ;D


•Researchers placed African dung beetles in a planetarium, and found that they could navigate just as easily with only the Milky Way visible as with a full starlit sky. Under overcast conditions, the beetles lost their way.

•Dacke's previous research showed that dung beetles use the Moon and celestial polarization patterns to keep moving in a straight line. Now they know that nocturnal beetles can stay on course even on moonless nights.

•“It was assumed insects could not use the stars because their eyes don’t have the resolution to see them,” explains Dacke. Navigating using the entire Milky Way eliminates the need to see individual stars, she says.

Now you know th dung beetles look at, and make use of, the Milky Way.   (

Title: Re: Special Sensory Perception
Post by: AGelbert on May 07, 2017, 03:03:32 pm

( The only Known Solar Powered Vertebrate   (

May 4th, 2017  at 5:05 pm by Elena Motivans

Although it looks like a regular salamander, the yellow spotted salamander is completely unique because its embryos use the sun for energy. They have algae inside of their cells that give them oxygen and carbohydrates. This feature that though, of course, necessary in green plants, is not so common in animals. A sea slug, aphid, and hornets are other creatures that share this ability. However, the yellow spotted salamander (Ambystoma maculatum) is the only known photosynthetic vertebrate! In fact, before this finding, it was thought to be impossible.

What is yellow spotted and secretly green? (

Yellow spotted salamanders actually look pretty normal; they aren’t green or anything. As the name suggests, the salamander is black with yellow spots. It is very common in North America. However, while the embryo is developing it undergoes photosynthesis. The reason why has to do with the salamander’s life history. The adults go to pools of water to mate and breed. Yellow salamanders only breed in ponds without fish because, otherwise, their larvae would be gobbled up. However, fishless ponds don’t contain very much oxygen. This problem is solved by adding algae into the mix.

The yellow spotted salamander (Ambystoma maculatum). Image credit: Brian Gratwicke.

It has been known for a long time that the eggs have a symbiotic relationship with algae; the eggs are bright green. Only recently, a researcher from Dalhousie University in Nova Scotia discovered that at a certain period in their development, embryos contain algae within their cells. Part of the green colour of the eggs comes from the embryos themselves.

A two-way relationship

The algae only move into the embryo after parts of the salamander’s nervous system has developed. Looking at time-lapse videos, you can see a flash of green at this time, which is a small algae bloom. The developing embryo releases nitrogen-rich waste at about this time, giving the algae food. Some algae could make it in the embryo at this time.

Once in the salamander, the algae stick near its mitochondria. Mitochondria create energy for animal cells from oxygen and a metabolic form of glucose. The algae appear to be giving oxygen and carbohydrates (the products of photosynthesis) directly to the salamander cells that contain them. The salamander could be using these byproducts to help its own energy production. In return, the embryo gives the algae nitrogen-rich waste and CO2. The algae have also been found in the oviducts of female spotted salamanders. The mother may have the algae already and be passing it down to its offspring by putting it into the egg sac.

The salamander’s eggs are green. Image credits: Fredlyfish4.

Uncommon ability  (

The yellow spotted salamander is the first vertebrate to have a photosynthetic symbiont. Before, it was thought to be impossible because vertebrates have an adaptive immune system that should destroy any foreign biologically material. Therefore, it was believed that vertebrates weren’t able to have a symbiont living in them. The spotted salamander may have gotten around this obstacle by turning their immune system off or by the algae not being recognised as foreign. However, the real answer isn’t known yet.

As mentioned, photosynthetic animals are extremely rare and all of the other known cases are invertebrates. The others use slightly different methods to harness solar energy, most commonly by containing some form of microalgae or cyanobacteria inside of them. For example, the emerald green sea slug, Elysia chlorotica, even has genes to sustain the chloroplasts that it contains. It can live for up to nine months without eating anything  :o.

Elysia chlorotica, the solar-powered sea slug, shares a few features with leaves. Image credits: Patrick Krug Cataloging Diversity in the Sacoglossa LifeDesk.

The pea aphid (Acyrthosiphon pisum) has a fungal gene that produces carotenoids.

Acyrthosiphon pisum apterae are pale green or pink with red eyes. The antennae of Acyrthosiphon pisum are 1.0-1.6 times as long as the body.

A bit differently, oriental hornets (Vespa orientalis) conduct electricity from their exoskeletons, silk, and comb walls. The hornet’s yellow bands contain xanthopterin that absorbs light and turns it into electricity. Unfortunately, this same material makes an inefficient solar panel.

Vespa orientalis is the largest wasp to be found in Europe and Malta (!faunafungi/maltawildlife.php?species=Vespa%20orientalis)

All in all, the yellow spotted salamander is unique in being able to photosynthesize. It has shattered previous perceptions and opened the idea that other vertebrates may also have a symbiotic relationship with algae.

So there you have it— salamander embryos that take energy from the sun.

Title: Re: Special Sensory Perception
Post by: AGelbert on July 31, 2018, 08:32:34 pm
Which Animals Have the Best Night Vision? 🐸

Human vision relies on cells in the retina that are known as rods and cones. Cones help us to see color, but only when there is enough light. Rods take over in low-light conditions, but we see only black-and-white images. Frogs and toads, however, have two types of sensitivities in their rods, allowing them to see colors even in the dark. In a series of experiments in 2017, researchers put frogs in completely dark environments and found that they were able to discern colors and find the exit -- much like the conditions they frequently face in real life.

Never in the dark:

“It’s amazing that these animals can actually see color in extreme darkness, down to the absolute threshold of the visual system,’ said professor Almut Kelber. “These results were unexpected.”

In other experiments, researchers studied how frogs and toads use their color vision when searching for a mate or hunting for food. Turns out that color means little in the hunt for a significant other.

Frogs are nocturnal, and their night vision benefits from a layer of tissue in their eyes called the tapetum lucidum. Animals with this tissue (such as cats) appear to have “eyeshine” in photos.