Robins Can See Magnetic FIelds

Robins Not Only Sense, But Can Actually SEE Magnetic Fields

By Dr. Becker


Story at-a-glance

  • Magnetoception is the scientific term for the ability to detect a magnetic field to perceive location, direction, or altitude. It is a skill only a handful of living things are known to possess, among them, certain birds.
  • While some birds can sense the Earth’s magnetic field, one type of bird – the robin – can actually see magnetic fields thanks to a special molecule in the retina. To robins, magnetic fields appear as patterns of light, shade or color superimposed onto what the birds see with their normal everyday vision.
  • This special magnetic compass is only found in the right eye in adult robins, though they are born with compasses in both eyes. Over time, the left eye loses its compass, and the bird’s magnetoception ability depends on good vision in the right eye.

Now here’s a word you may never come across in your lifetime (unless you enter a lot of spelling bees): Magnetoception (also called magnetoreception). Do you know what it refers to? It describes the ability to detect a magnetic field to identify direction, altitude or location.

Magnetoception is a skill only a handful of creatures seem to have, including bacteria, some invertebrates (fruit flies, honeybees, and lobsters), homing pigeons, domestic hens, certain mammals, turtles, sharks and stingrays. Humans may or may not possess the ability, depending on who you ask.

Robins Not Only Sense, But Actually SEE, Magnetic Fields… But in Only One Eye

Some birds can sense the Earth’s magnetic field and orient themselves accordingly. As you can imagine, this is a huge benefit for the “frequent flyers” of the avian world, migrating birds.

But one type of bird in particular, the robin, can actually see magnetic fields thanks to a special molecule called a cryptochrome in the retina. The fields appear as patterns of light, shade or color superimposed onto what the birds normally see.

Scientists have learned that in robins, the magnetoception ability is dependent on good vision in the right eye. If the right eye is covered, the birds become disoriented when they fly, but if the left eye is covered, they navigate without a problem. This means the robin’s vision in the right eye acts as a doorway for its magnetic sense. If there is darkness or cloudiness in the right eye, the door stays shut, but light in that eye opens the door and activates the bird’s internal compass.

The guidance mechanism seems to work in such a way that the magnetic field-generated patterns of light, shade or color overlaying what a robin normally sees change as the bird turns and tilts its head during flight. This provides a visual compass composed of contrasting shades of light. But the compass doesn’t depend solely on light – the birds must also have a clear image with their right eye in order to accurately navigate. Their magnetic sense is only a transparent overlay to the images their normal vision provides. If that vision is impaired in any way, the magnetic sense is of no use. (Imagine trying to follow your car’s GPS navigation instructions with a couple inches of heavy wet snow covering your windshield.)

Experts believe robins probably require a clear, focused image to distinguish between inputs from their visual and magnetic senses. Since the magnetic field lies on top of what is seen through normal vision, and both incorporate differences in light and shade, it would seem the birds could become easily confused. However, the images the birds see through normal vision tend to have sharp transitions between light and shade, whereas changes in the patterns superimposed by magnetic fields are smoother and more gradual. Birds are probably aware that sharp changes in contrast are due to the boundaries of actual objects, while more subtle changes are the result of magnetic effects.

Baby Robins Possess a Magnetic Compass in Both Eyes, But Lose the Left One as They Mature

While adult robins have a magnetic compass in their right eye only, as babies, they had a compass in each eye. It seems they lose the left one as they mature.

The change from both eyes to just the right eye occurs gradually. In robins that are no longer babies but not fully grown, the magnetic compass in the left eye can be revived for a time by covering the right eye. According to scientists, this means the eyes themselves aren’t changing. Instead, the brain begins processing input from the eyes in different ways.

A near equivalent in humans is right- or left-handedness. The hand we ultimately prefer as adults only becomes dependably dominant around the age of four or five.


Swimming With Dolphin Progams — Bad Idea

The Alarming Truth About “Swim with the Dolphins” Programs

October 14, 2013
By Dr. Becker

Story at-a-glance

  • From the outside looking in, swim-with-the-dolphin (SWTD) programs appear to be a fun, safe opportunity for people to interact with one of the most appealing animals on the planet, the dolphin.
  • Upon closer inspection, however, like so many wild animal attractions designed by humans for humans, SWTD programs are bad news for dolphins (and they’re not all that safe for people, either). Dolphins are uniquely unsuited to captivity for a variety of reasons including their social structure and natural drive to swim long distances, dive down hundreds of feet, and spend most of their time underwater.
  • SWTD attractions in countries outside the U.S. pose an even bigger problem due to lack of regulation and poor conditions. Abuses include dolphins kept in small pools surrounded by jagged, rusty fences or near sewage outfalls, diets of rotten fish, disease, and starvation.
  • Wild SWTD programs are also a bad idea. Studies show that the presence of tourist boats and swimmers among wild dolphin populations is incredibly stressful for the animals, preventing them from resting, feeding, and caring for their young.
  • If you’re interested in the welfare of dolphins and want to help, avoid SWTD programs, and also consider avoiding resorts, cruise lines and other businesses that promote the exploitation of dolphins for entertainment purposes.

By Dr. Becker

In recent years, “swim-with-the-dolphin” adventures have become increasingly popular with resort-goers and vacationers visiting tropical ports aboard cruise ships.

If you don’t think too deeply about it, a swim-with-the-dolphin (SWTD) experience may seem like a unique, harmless way to get an up-close look at some of the world’s most intelligent, fun-loving sea mammals.

But what many people don’t know or haven’t considered is that most attractions designed to expose humans to wild creatures don’t enhance the lives of the animals involved. Sadly, this includes the SWTD industry. And not only are these programs bad for dolphins, they aren’t entirely safe for people, either.

Dolphins Are Exceptionally Incompatible with Captive Environments

Dolphins have evolved to live and thrive as wild sea mammals — not within the confines of an exhibition tank or a sea pen built into an artificial lagoon.

Dolphins in the wild live in large groups called pods, often in close family units. Social bonds are meaningful and long lasting — sometimes for a lifetime. Captive dolphins, on the other hand, spend their lives interacting with a handful of unfamiliar dolphins that appear and disappear at the whim of the humans running the show.

Wild dolphins often travel long distances each day. They may swim in a straight line for a hundred miles, move along a coastline for several miles and then swim back to their starting point, or they may spend several hours or days in a certain spot. Dolphins living in captivity swim in a circle around a tank or within the small confines of some other artificial habitat. Caged dolphins are often seen swimming around and around in their tanks, peering through the glass or other barricade, or floating listlessly on the water’s surface. These behaviors indicate boredom and psychological stress.

In the ocean, dolphins can dive down several hundred feet and can remain underwater for 15 minutes or more. They spend only a small amount of time – 10 to 20 percent – on the surface. Captive dolphins, sadly, spend up to 80 percent of their time at the surface of the water waiting for food or attention.

According to the Humane Society of the United States (HSUS):

“The sea is to dolphins much as the air is to birds—it is a three-dimensional environment, where they can move up and down and side to side. But dolphins don’t stop to perch. They never come to shore. Dolphins are always swimming, even when they “sleep.” They are always aware, and always moving.

Understanding this, it is difficult to imagine the tragedy of life in captivity for these ocean creatures.”

Imprisoning Wildlife for the ‘Benefit’ of Humans

There are from 14 to 18 swim-with-the-dolphin attractions in the U.S. The marketing of these programs promotes the experience as “eco-friendly” and “educational.”

There are also so-called “dolphin-assisted therapy” programs for children and adults with disorders like Down’s syndrome, autism, cerebral palsy, head and spinal injuries, or cancer. In fact, there is no scientific data to indicate that interacting with dolphins has any greater therapeutic benefit than programs involving dogs, horses, or other domesticated animals. As the HSUS accurately points out, “There is no need to imprison wildlife to benefit humans.”

Swim-with-the-dolphins operations in other countries pose an even bigger problem due to lack of regulation and poor conditions. Abuses cited by the HSUS include overworked pregnant female dolphins; dolphins kept in small pools surrounded by jagged, rusty fences or near sewage outfalls; diets of rotten fish; disease; and starvation.

Most SWTD programs outside the U.S. capture their dolphins from the wild. Not only is this practice extremely traumatic for wild dolphins, often resulting in a life-threatening condition known as capture stress or capture myopathy, it can also have a negative impact on the pods from which the dolphins are taken.

SWTD Programs Pose Health Risks to Both Humans and Dolphins

Some captive dolphins will attempt to assimilate to their environment by looking to humans to take on the roles normally filled by other dolphins in the pod. Some of the behaviors noted include submission or sexual aggression around humans, as well as agitation and aggressive behavior resulting from the stress of forced interaction.

These behaviors can result in serious danger to swimmers, and in fact, SWTD programs have reported injuries to humans including tooth rakes, lacerations, broken bones, internal injuries and shock.

For the dolphins, unnatural exposure to people can result in human bacterial and viral infections, and stress-related conditions like ulcers.

Swimming with Wild Dolphins Is Also a Bad Idea

A study conducted in 2010 of bottlenose dolphins off the coast of Tanzania1 found that SWTD programs in the wild are also highly traumatic for the dolphins, preventing them from resting, feeding, and caring for their young. Tourists swimming very close and trying to touch the dolphins proved incredibly stressful for the animals.

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Sound/SHockwave Treatment for Pets

Try Shockwave Therapy When Your Pet Is In Pain or Isn’t Healing

October 11, 2013
By Dr. Becker

Story at-a-glance

  • Shockwave therapy, or ESWT, uses acoustic energy directed to target treatment areas of an animal’s body. The shockwaves trigger the body’s repair mechanisms, enabling healing and long-term improvement of a variety of conditions.
  • In ESWT, high-intensity sound waves interact with the tissues of the body, leading to development of new blood vessels, reversal of chronic inflammation, stimulation of collagen and dissolution of calcium build-up.
  • Conditions in companion animals that can be effectively treated with shockwave therapy include hip and elbow dysplasia, degenerative joint disease, osteoarthritis, tendon and ligament injuries, non- or delayed healing bone fractures, back pain, and chronic or non-healing wounds.
  • Studies of shockwave therapy for dogs have shown positive results in improving bone healing, soft tissue damage, joint inflammation, and both the progression and pain of osteoarthritis.
  • ESWT treatments are loud and can be painful, so animals are sedated during sessions. Treatment frequency and duration depends on the strength of the shockwaves and the number of locations being treated.

Shockwave therapy — officially called extracorporeal shockwave therapy (ESWT) – is generally understood by most of the veterinary community as useful in treating musculoskeletal injuries, osteoarthritis (OA), and wound healing in horses. According to Clinician’s Brief, the use of ESWT to aid healing in companion animals like dogs and cats is not as well recognized.

Many people hear the word “shockwave” and immediately think of an electrical shock. But the shockwaves used in ESWT are high-energy sound waves (acoustic energy) that are directed to a target treatment area on an animal’s body. The shockwaves trigger the body’s own repair mechanisms, which speeds healing and provides long-term improvement.

How ESWT Helps the Healing Process

ESWT has been used in human medicine for over 20 years to provide non-invasive treatment for urologic and orthopedic conditions.

ESWT employs electrohydraulic technology to generate shockwaves. The high-intensity sound waves interact with the tissues of the body, leading to a host of beneficial effects including development of new blood vessels, reversal of chronic inflammation, stimulation of collagen and dissolution of calcium build-up. This activity creates an optimal healing environment, and as the damaged area returns to normal, pain is alleviated and functionality is restored.

When shockwave therapy is applied to areas of non-healing tissue, it may trigger release of acute cytokines that stimulate healing. Accompanying pain relief may be the result of increased serotonin activity in the dorsal horn (located in the spinal cord).

Conditions Successfully Treated with Shockwave Therapy

Shockwave therapy is known to be beneficial in treating the following conditions in companion animals:

Hip and elbow dysplasia Painful scar tissue
Degenerative joint disease (hip, elbow) Chronic back pain
Osteoarthritis Lick granuloma
Spondylosis (degeneration of joints in the spine) Sesamoiditis (chronic inflammation of bones in the foot)
Tendon and ligament injuries Chronic wound care
Legg-Calve-Perthes disease (degeneration of the head of the femur bone in the hind leg) Trigger points
Non-healing (non-union) or delayed healing (delayed union) fractures Acupressure points

Actual Results of ESWT for Dogs

According to Clinician’s Brief:

  • Of 4 dogs treated for non-healing fractures, 3 had significant improvement in bone healing following ESWT treatment.
  • In a study of dogs with distal radial fracture non-unions (a break near the bottom of the front limb, just above the wrist joint), all dogs that received ESWT showed complete bone healing after 12 weeks, while no dogs in the control group achieved complete bony union.
  • In a study of dogs with lameness resulting from soft tissue shoulder conditions, 88 percent showed improvement after shockwave therapy, with no surgical intervention.
  • ESWT was also shown to significantly reduce distal ligament thickening in dogs with inflammation of knee joints following surgery for a CCL rupture.
  • Shockwave therapy has proved beneficial in promoting the development of new blood vessels at the bone-tendon interface of the Achilles tendon in dogs.
  • ESWT has been shown to modulate osteoarthritis in animals by decreasing production of nitric oxide in joints and inhibiting cell death in healthy cartilage. Shockwave therapy can also be beneficial in managing the pain of arthritis.
  • Studies have demonstrated positive results in joint range of motion and peak vertical force in dogs with knee, hip and elbow arthritis.

Currently, there are only unpublished case reports on shockwave therapy for treating chronic wounds in small animals. However, based on its mechanism of action, ESWT may prove valuable in managing skin flaps and difficult and chronic wounds.

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