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.
Last week, “A Dog’s Purpose” was released in theaters. The movie—which “shares the soulful and surprising story of one devoted dog who finds the meaning of his own existence through the lives of the humans he teaches to laugh and love”—has gotten mixed reviews, and I haven’t seen it yet, but the commercials have been making me miss my old dog for weeks.
A recent study shows that I, and the 75% of “A Dog’s Purpose” viewers, might not be alone in our undying devotion to our childhood pets. The study, conducted by the University of Cambridge, highlighted “the importance of early adolescents’ pet relationships” as “participants derived more satisfaction and engaged in less conflict with their pets than with their siblings.”
At this point, you may be shaking your head in disappointment that the study came to what might be considered an obvious conclusion—one’s pet rarely participated in a rivalry, siblings, however, probably did. My dog, for one, was not known to bicker. Researchers believe the fact that “pets cannot understand or talk back,” may be “a benefit as it means they are completely non-judgmental,” allowing for levels of disclosure that might not be possible with a sibling.
According to Nancy Gee, Human-animal Interaction Research Manager at WALTHAM and a co-author of the study, understanding the “social support that adolescents receive from pets” may help us understand and promote the positive benefits of a pet’s influence during adolescence on “psychological well-being later in life.”
The study, which involved 77 12-year-olds, measured child-pet relationships using “a pet adaptation” of the Network of Relationships Inventory (NRI). The NRI traditionally assesses relationship characteristics “such as companionship, conflict, instrumental aid, satisfaction, antagonism, intimacy, nurturance, affection, punishment, admiration, relative power, and reliable alliance for each type of relationship.”
Researchers drew conclusions about the difference between male and female interactions with pets, finding that “girls reported more intimate disclosure, companionship, and conflict with their pet than did boys” despite both genders being “equally satisfied” with their pets. These findings seem to contradict previous research that found “boys report stronger relationships with their pets than girls do.” In addition, owners of dogs reported greater satisfaction than owners of other kinds of pets.
So, whether you liked “A Dog’s Purpose” or not, it seems that pets really do have the potential to live forever in our minds and emotions—if not through reincarnation.
Since Patella vulgata, the common limpet, are living, breathing organisms, one would expect them to have almost nothing in common with concrete; however, a recent study conducted by David Taylor, professor of materials engineering at Trinity College Dublin, indicates otherwise.
Common limpets, which you may recognize from trips to the beach (if your local beach is somewhere between the Mediterranean and the Lofoten Islands of Norway), are fascinating little creatures. “They have several features that make them interesting from a biomechanics point of view,” explains Taylor in an article from ScienceDaily. “They have evolved mechanisms for adhering very strongly to … underlying rock and are also equipped with a set of very hard teeth.” Not to mention, “the hard-working creatures quickly patch over small holes [at the apex of their conical shells] with new biological building material from within.” These small holes generally result from impacts with rocks as the limpets are tossed by rough seas. According to the article published in the Journal of Experimental Biology, “it is proposed that the apex [of the limpet shell] acts as a kind of sacrificial feature, which confers increased resistance but only for a small number of impacts.” Still, this self-healing ability is an interesting phenomenon, especially once experiments revealed that the patched shell was as strong as the original, undamaged shell.
Unfortunately, the experiments also revealed that, like concrete, the limpet shells were susceptible to spalling—a surface failure characterized by the flaking off of small bits of material due to mechanisms like impact, corrosion, or weathering—after repeated impacts. Scanning electron microscopy identified delamination, or a separating of the ‘laminated’ layers of the shell, which lead to a loss of material by spalling.
David Taylor concluded that while it is “really interesting that [limpets] are still at risk from spalling weaknesses … spalling is evidently one problem that doesn’t have a perfect solution—whether you are a concrete foreman overseeing a building site or a limpet trying to speedily repair his or her home on the seashore.”
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.”