The Animal Science Blog is the place for conversation and discussion about scientific and technological topics related to pets, livestock, and other animals. See how cutting-edge advances help - or hinder - species around the world.
In the process of researching my last blog about Bananapocalypse, I discovered a surprising number of uses for banana peels. Did you know that you can remove a splinter, or a wart, by taping the peel over the splinter or wart? Also, rubbing the peel on a bruise helps make it disappear. Banana peels buried around plants that attract aphids will deter the pests from taking up residence. Check out other handy banana peel hints here and here.
I did not know that recent research has discovered, entirely serendipitously, that Volatile Organic Compounds (VOCs) released by a common bacterium can successfully treat White Nose Syndrome (WNS) in bats. The Georgia State University researchers who made this discovery were looking at ways to delay banana ripening, using bacterial VOCs. One of the researchers noticed that bananas exposed to a particular bacterium, R. rhodochrous, didn’t get moldy. Its VOCs have an antifungal property. Chris Cornelison, now a postdoc at Georgia State, made the mental connection between the fungal WNS in bats and the potential to use bacterial fumes to treat it.
WNS is decimating bats
For those of you who aren’t familiar with it, the plague of WNS started decimating insect-eating bat populations in 29 states and five Canadian provinces during the winter of 2007-2008. The culprit in this disease is the cold-loving fungus Pseudogymnoascus destructans. The fungus attacks hibernating bats, causing behaviors such as daytime flights during winter. These behaviors consume fat reserves stored for the hibernation period. Eventually the fungus damages the bats’ wings and causes water and electrolyte loss.
Given the number of bats that overwinter together in caves, the fungus can easily affect thousands of bats. The USGS estimates that up to 80 percent of bats in the northeastern United States have died from WNS. The precipitous decline in bat populations is expected to affect agriculture, since bats eat insects that harm crops. Mr. Best in Show and I used to see bats flying at night around our house out in the middle of nowhere and, occasionally, flying low in our bedroom. For the past five or six years, though, we haven’t seen a bat at all. Very sad.
Could R. rhodochrous kill the fungus in bats?
Cornelison exposed petri dishes of the WNS fungus to fumes from R. rhodochrous and, as he said, “the first exposure seemed too good to be true.” This is great news for groups who’ve studied the fungus, trying to understand disease pathology and transmission. Scientists knew of nothing that could halt the fungus from continuing to spread, beyond advising spelunkers to take care not to carry the fungus between caves. So Cornelison’s discovery offered the first hopeful news in the battle to save the bats.
Enter The Nature Conservancy in Tennessee. They knew they needed to address WNS head-on. The Conservancy and Bat Conservation International decided to cooperate on a study, treating bats in the field with the VOCs generated by R. Rhodochrous. Bats were exposed to the VOCs then placed in a cave to hibernate. When the bats broke hibernation, they had no detectable signs of WNS. Some had so much wing damage that they will live out their lives in a protected environment. The other, healthier bats were moved to a wild cave.
Fruit bat eating banana via YouTube
Will bacterial emissions solve the WNS problem?
Biological control agents often have unintended consequences, where the agent itself becomes a problem. With this in mind, researchers are proceeding carefully with using VOCs in bat caves. One possibility for treating bats and/or their caves would be to expose an entire cave to the gasses, rather than treat individual bats. Before trying this in the wild, researchers have to find out what such exposure would do to cave ecology. And they have to make sure that the VOCs don’t have unexpected deleterious effects on the bats or other animals. So far, though, this treatment looks promising.
This story has a secondary point: the role of serendipity and non-linear thinking in the advancement of science. The researchers wanted to find a way to retard banana ripening. If no one had realized that the R. rhodochrous VOCs had fungicidal effects—if Chris Cornelison didn’t know about WNS in bats—I wouldn’t be writing this blog. A graduate school professor of mine told me that he accidentally found a book that changed the direction of his Ph.D. research, after he’d already spent weeks following references and compiling a bibliography. You just never know, do you?
Hand tying silver wire onto a bird’s leg by John James Audubon in the 1700’s evolved to become today’s factory manufactured rings shaped from various kinds of metal or molded polymers, stamped with letters and numbers. With a reliable way of identifying individual birds established through the centuries, banding, or ‘ringing’ as it is called in Europe, evolved with the industrial revolution. New banding tools were invented out of necessity to band different bird legs, so as not to constrict and harm the bird's leg. Plastic polymer leg bands were also created where a tool would not be required. These bands are produced as a coiled plastic band resembling a child’s slap-on bracelet toy.
Molded polymer bird bands are typically made out of celluloid and Reoplex® (Poly 1,3-butylene adipate), as well as polyvinyl chloride or Darvic. These materials are light enough where they will not impede a birds flight or foraging habits. Since a typical passerine or songbird only weighs 15 to 30 grams, or 0.5 to 1 ounce, a plastic bird band weighing around .01 ounces, or 0.3 grams overall, might not have any negative effects on a bird wearing it. For example, a cardinal weighs approximately 44 grams or up to 2.0 ounces and a black-capped chickadee weighs approximately 9 to 14 grams. Also, to accommodate different sized birds, there are over 30 different standard sizes of bands that can accommodate the leg of a hummingbird to a bald eagle or trumpeter swan and they can range in widths from 2 mm to 27 mm.
As mentioned, bird bands can be made from various polymers or metals, such as aluminum, and can come in a myriad of colors. Aluminum bands that have different colors use an electrochemical process of anodizing the aluminum surface, so a secondary process of adding a coloring or corrosive preventing component can integrate onto the aluminum substrate. Smaller bands, made with metals or polymers, typically have butt ends and are usually imprinted with letters, numbers, symbols, and even country codes for distinguishing birds of the same species. Different organizations, state agencies and environmental research groups will use multiple bands on the same bird using different colors and combinations of aluminum and plastic bands to distinguish where the bird was banded and who is doing the banding.
Determining the type of band to use on a specific species of bird is based on how long a particular bird lives and in what environment the bird typically inhabits. Does it frequent a fresh water lake or river or does it forage and breed in a more corrosive environment, such as a salt water marsh? Metal and polymer bird bands have a life expectancy as well. Materials degrade and wear out after prolonged exposure to the elements, so choosing the appropriate band for a bird requires some knowledge of the bird’s habits.
Smaller birds such as terrestrial songbirds and hummingbirds, that typically have a shorter lifespan (~2 to 8 years) and may have exposure to freshwater such as rain or the occasional backyard bird bath visit, only require a band made of plastic or aluminum. Larger birds such as ospreys and bald eagles, which can live up to and beyond 30+ years and in many cases encounter salt water habitats, require a metal band that is more resilient to the environment. To serve this purpose, bands made from stainless steel, aluminum, copper, Monel, or incoloy (a type of superalloy) are typically more expensive, but have a much longer lifespan and usually are made with a robust fastening feature such as a lock-on rivet. These bands are ideal for larger birds requiring resiliency and longevity. The hardier metals deter these large raptors from removing the band with their strong bills. Lock-on riveted bands are usually attached using a device called a ‘pop-rivet gun’ developed by Charles Sindelar, an ornithology professor formerly at the University of Wisconsin.
Although bands are typically attached around a bird’s leg, there are other variations of aluminum and plastic polymer bands created for different sized birds. For larger marsh birds and waterfowl, such as geese and herons that have long necks, non-heat conducting, expandable and flexible vinyl neck collars are used. These neck bands will allow a long-legged wading bird to move through a marshy area without a band on its legs catching on debris.
Other waterfowl such as the common loon have thin, almost rectangular legs. These birds require a specially made flattened band that looks like a squashed ring, and that will fit comfortably on the bird’s leg, allowing it to paddle unencumbered.
Bird banding has been used for over 100 years and continues to be used as an inexpensive means of tracking a bird, but it does have limitations. The banded birds must be either observed or re-caught to be able to identify the banding code on the band or ring. There is mortality as well and not all birds are re-seen or recaptured.
In part three of this series, we’ll look at another technology that was developed and being used to better track where birds go – electronic transmitters.
A day in the life of a lab rat is usually pretty miserable, as one could imagine. You’re likely poked, produced, bothered, or even starved – all in the name of science.
A recent study highlights some rats that were part of a fun-filled study that yielded some important results. The study, published November 11th in Science showed that nerve cells in the brain process glee in a specific way.
For centuries, scientists have tried to solve the mystery of tickling. Many studies have been done on the subject, as the mysterious reaction is often associated with some of the most pleasant human emotions. Scientists knew rats responded to a tickle, but how the brain created that reaction and emotion was unknown.
When tickled, the rats laughed and jumped for joy, an acrobatic feat called “Freudensprünge” or joy jumps. By documenting the levels of laughter, study coauthor Shimpei Ishiyama of Humboldt University of Berlin found that the belly of the rat is the most ticklish.
The response, scientists believe, is created partially by nerve cells in the somatosensory cortex. In humans, this part of the brain is usually associated with touch perception. When tickled, many of the rat’s nerve cells in this part of the brain became active.
But additional experiments found active nerve cells when the rats were chasing a tickling hand without being touched. This suggests the cells are responding to something specific about a tickle, not just touch in general. Also, when the researchers used electrodes to stimulate the somatosensory cortex in untouched rats, the rats laughed.
The study also found that mood can affect how the rats react to being tickled, much like a person who doesn’t want to be tickled might appear stressed. Nerve cells in the somatosensory cortex were less likely to show activity when the rats were anxious. They also released less laugh-like noises.
Not only did this study make progress for scientists to understand human emotion, but it certainly seemed like a lot of fun.
“Science has been obsessed with bad things,” Ishiyama said in a PopSci article. “It’s important to also study positive motivations like happiness or fun.”
Autumn is nearly finished and many birds that migrate have flown south for the winter. Have you ever looked up at a V-shaped formation of flying Canada geese and wondered, “Where exactly do they go for the winter?”
Birds of all shapes and sizes, from songbirds to waterfowl to birds of prey, such as hawks and falcons, migrate, but not all ‘fly south for the winter.’ Some birds migrate locally to where food sources are and stay north or in the United States all winter long. Other birds fly between their breeding grounds of the Canadian boreal forests to their wintering grounds in the jungles of Central and South America. So how do we know where they all go? Thank the constant innovations in technology to give us the answers.
This series will delve into the details of different types of tracking devices, from unpowered tiny polymer bird leg bands to solar battery powered transmitters bird backpacks. These devices shed light on the science of bird behavior and in the end where exactly different birds really do go for the winter.
A Little History - Silver Wire as Identifiers and Banding Birds
Some of you may have heard of the most notable cataloguer of birds here in the United States: John James Audubon. Audubon was born in what is today known as Haiti, which was known as Hispaniola during the 1700’s and under the control of France then led by Napoleon. With war raging in Europe at the time, Audubon’s father wanted to save his son from being drafted into Napoleon’s Army, and so he shipped John off to America where he settled in Mill Grove, Pennsylvania. In the bucolic landscape of his new home Audubon discovered various birds he had not seen in his native Hispaniola. He noticed species of birds nesting on his farm during the spring and seeing the same looking birds nesting again in different trees on his farm the following year. Audubon wondered if they were the same birds that returned each year and concocted an idea of using silver wire tied around a nesting bird’s legs to see if it really was the same bird. To his delight and luck, he noticed the following spring that the same birds returned to his farmstead with the silver wire and tags still attached. This was the first time “banding” of birds was initiated in the young United States. Audubon’s passion for birds was fueled by this experiment, and led him to document this young nation’s birds through his famous paintings, which are still renowned today around the world.
Banding birds was nothing new though. Four hundred years before Audubon and on the other side of the world, in western China, Mongolia, and the Middle East, the use of falcons and Golden Eagles were typically employed for hunting. During the 1200’s, these Asian falconers affixed at silver tablet to the feet of the bird, which had the owner’s name imprinted upon it, to identify the bird as owned by another. But even before that, pigeons were ‘banded’ with tiny pieces of parchment with inscribed messages by the Romans to send messages to far away generals throughout the Roman Empire. Although these different forms of banding did not identify exactly where birds ‘migrated’ to, it did establish a way to identify the bird when it was found.
Check out next week’s post to learn about modern bird banding technology.
Most things that are manufactured have an intended use, even if disposable. Balloons, however, are created with the intention of being thrown out, released into the sky, or worse. It would seem most are not kept for more than a few hours, or they linger around until the helium inside decays and then they’re thrown out.
It’s almost a mockery of what’s emblazoned on most of them—“Congrats,” “Happy Birthday,” “Welcome Home”—that they end up killing our ecosystems.
Balloons not only possess a hazard to animals when eaten, but the ribbons and strings attached can cause dolphins, fish, whales, and turtles to become tangled and ultimately die. Many marine animals mistake balloons, both Mylar® and latex, for jellyfish—a popular snack.
In fact, when latex balloons fly high enough, they pop in such a way that leaves them looking like they have several tentacles and float through the water almost exactly like a jellyfish does. The resemblance is almost uncanny.
Bighorn sheep in parts of southern California are impacted by balloons too, among other mammals. They have four-chambered stomachs and do not chew their food completely as they eat; meaning pieces often get trapped in their systems during the digestion process. A study found sheep deceased with balloon strings hanging from their mouths and within their digestive tracts.
These party favors also have a significant impact on the environment. Balloon release parties are often an honorary event in which people release a cluster of balloons to honor someone who has died or even in celebration of happier events, like a wedding or graduation. Once released, they travel thousands of feet into the sky.
The real damage is done when they make it back to the ground, though. Latex balloons do break down over time, but Mylar balloons pose a more serious risk. They’ve been marked as non-biodegradable and are made from metalized polyester, which is harmful both in production and in disposal. The National Association of Balloon Artists and Suppliers has spoken about the impact of Mylar balloons specifically. In a series of recommendations, the organization warns against using Mylars at all, while offering some safety tips to make latex balloons as minimally harmful as possible.
While they may be colorful and fun, the impact of these floating favors is serious. They are a danger to our animals and our ecosystems. Perhaps the next time you plan a party, consider a more sustainable way to showcase the celebration.