Magnetic Animal Navigation / Human Possibilities

In a comment on a previous post (reblog from The Science Geek) I suggested that human behavior may be under the influence of physical processes and forces in the environment to a greater degree than we currently understand or are willing to accept. After all, humankind has invested an enormous sum of time, energy and thought into explaining our existence in supernatural terms, and this includes the pseudo-sciences of psychology and psychiatry.

How birds use Earth’s magnetic field to navigate

Australian Geographic, by Peter Meredith, May 28, 2014 http://australiangeographic.com

Can birds see the Earth’s magnetic field? The latest research on navigation suggests they can and even hints that humans may be able to detect it, too.

How birds us magnetism as a compass Here’s how scientists think the avian compass works. The organs for this mechanism are believed to be in the right eye, but perhaps in the left eye also. Research indicates this magneto-receptor may be based on pigment proteins in the retina known as cryptochromes. The Earth’s magnetic field seems to induce a chemical reaction in these proteins when certain light wavelengths (mostly blue) strike the retina. This results in signals being sent from the eye to the brain via the optic nerve. Some scientists believe this may mean a bird can actually see the magnetic field. The precise nature of the chemical reaction in cryptochromes is believed to vary according to the angle of the magnetic field lines – their inclination – as they pass through the eye. Inclination, therefore, is a strong pointer to direction. Angled lines may indicate that a bird is close to a pole; horizontal lines may mean the bird is at the Equator.

For the moment, what the magnetic field looks like to a bird is anybody’s guess. “The magnetic compass is a side-function of the eye, and magnetic information is primarily mediated by the visual system,” Roswitha Wiltschko says. “Yet birds must separate the magnetic from the visual information somehow. How birds perceive this information is impossible to tell.”

Scientists Discover The Body Part Used To Sense The Earth’s Magnetic Field

June 18, 2015 by Josh L Davis, IFLScience

From salmon to geese, to turtles—many animals move and migrate in relation to the Earth’s magnetic field. With no obvious sense organ to detect the magnetism, it’s long puzzled scientists as to how they manage this. But a group of researchers from the University of Texas think they may have found the answer. After observing how a type of worm wriggles through soil, it was discovered that they possess a sensor on the end of a particular type of neuron, which allows them to align themselves in the correct orientation. Due to the similarities in brain structure across species, the researchers claim that it’s likely other animals share this sensor too.

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Inside the head of the worm C. elegans, the TV antenna-like structure at the tip of the neuron (green) is the first identified sensor for Earth’s magnetic field. Andrés Vidal-Gadea /University of Texas

“Chances are that the same molecules will be used by cuter animals like butterflies and birds,” said Jon Pierce-Shimomura, who co-authored the paper published in the journal eLife. “This gives us a first foothold in understanding magnetosensation in other animals.”

The nematode worms, called Caenorhabditis elegans, are widely used for all sorts of biological studies, from aging to addiction. Whilst documenting the behavior of specimens from different parts of the world, the researchers noted that they didn’t all move down through the soil, as they normally do. They found that depending on where the worms were collected – either Hawaii, England, or Australia – the animals moved at the precise angle of the magnetic field that was equivalent to the down direction of their ‘home’ soil.     

The neuron suspected of housing the magnetic sensor was already known to be used to sense humidity and carbon dioxide levels. But when the researchers genetically modified the worms to have a break in the neuron, they found that the worms were not able to orientate themselves in the soil. In addition to this, they were able to show that changes in the magnetic field activated the neuron.

It was previously assumed that the worms migrated down by using gravity as a cue, but this finding suggests otherwise. “I’m fascinated by the prospect that magnetic detection could be widespread across soil dwelling organisms,” said Andrés Vidal-Gadea, the study’s lead author.

Previous research has found that certain brain cells in pigeons also handle information about magnetic fields to help them navigate, and others have suggested that certain cells in the noses of trout respond to magnetism, but this is the first time that researchers have managed to find a specific neuron that responds to the magnetic field. They think that this new knowledge could help protect crops from pests by manipulating the magnetic field in the area.

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And from wondergressives.com

Pooping Dogs Perceive Earth’s Magnetic Fiel

by . in Science, 4 Jan, 2014

 

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