Thursday, July 7, 2016

Summer Vacation!

It is time for this blogger to unplug and unwind! But don't worry, I will be back in September with more stories of why animals behave the way they do, how their bodies function, and how to pursue your animal-related dreams.

Be curious!

Tuesday, July 5, 2016

A Tiny Surprise in Regards to Regeneration (A Guest Post)

By Jessica Klein

The ability to regenerate limbs and tails is nothing new to reptiles and amphibians. Many lizards are able to drop their tails to escape an enemy, whereas salamanders have been known to grow back entire legs with muscle after being attacked by a predator. These regenerative characteristics have been seen to some extent in rabbits and pika before 2012, but were later discovered to occur extensively in, surprisingly enough, small African spiny mice.

One of the African spiny mouse species. Photo by Ashley Seifert and Tom Gawriluk.

In a study done by Ashley W. Seifert and Megan G. Seifert at the University of Kentucky, Todd M. Palmer and Malcolm Maden at the University of Florida, Stephen G. Kiama at the University of Nairobi, and Jacob R. Goheen at the University of Wyoming, African spiny mice were studied in order to view the extent of their regenerative properties, why they might occur, and the physiological processes that make it happen.

The rodents were captured in Kenya, where researchers learned that vigorous movement during handling caused the skin of African spiny mice to come apart. One mouse was reported to have an open wound that took up 60% of its back, just from being handled! Therefore, Dr. Seifert measured the amount of strength it took to tear the skin of spiny mice using something called a Hounsfield tensometer. He took the measurements from that tool and graphed them on a plot, creating something called a stress-strain curve which showed how much strength it took to tear the skin of the mouse.

The strength measurements revealed that the skin of these species was 77 times weaker than average mice, explaining why their skin tore so easily during the handling process. In order for the African spiny mice to survive such large injuries due to their extremely fragile skin, it would be beneficial to heal quickly or regenerate the skin. This is exactly what Dr. Seifert discovered.

An African spiny mouse shows
the regenerative process with
(1) being before the wound
(2) being after the wound and
(3) showing how the wound was
completely healed after 30 days.
Figure from Seifert, et al., 2012.
After the strength measurements were completed, the rodents were anaesthetized and had 4mm and 1.5cm wounds made on their skin, as well as 4mm holes punched in their ears in order to view the regeneration process. In an average rodent, the repair of a 4mm skin wound takes around 5 to 7 days and is accompanied by a significant amount of scarring. However, in the African spiny mouse it only took 1 to 2 days for scabbing of the skin wound to occur with new cells forming on the outside of the wound to repair it. After just 10 days, the ear of the mouse was fully healed. In the ear punches, there were no signs of scarring that would have been expected in a rodent, and healthy cartilage had formed. By the 21st day of the experiment, African spiny mice had developed new hair follicles and healthy new hair covering the once wounded area. In total, Dr. Seifert discovered that African spiny mice were capable of regenerating their skin, hair follicles, and sweat glands.

Dr. Seifert suggested the skin of African spiny mice is fragile because it allows them to escape predators. This would require a quick healing time to reduce the chance of infection and ultimately death in the mouse after escaping. This is why they may have gained the ability to regenerate their skin, but how exactly does this happen? Dr. Seifert and his research team recently showed that, in these species, it occurs through a process known as epimorphic regeneration. This is when a blastema (a mass of immature, unspecialized cells) forms where the wound once was. These cells are capable of turning into whatever type of tissue was present in that area. This particular method of regeneration is how salamanders are capable of regenerating their limbs. Again, more research would need to be done in order to confirm or deny this. However, one thing is true, and that is that more research into this could prove to be useful in the future of medicine when it comes to healing critical and invasive injuries. By discovering the physiological process behind this, and then being able to replicate it in a lab, researchers may discover ways to heal injuries faster.




Works Cited

Seifert, Ashley W., Stephen G. Kiama, Megan G. Seifert, Jacob R. Goheen, Todd M. Palmer, and Malcolm Maden. "Skin Shedding and Tissue Regeneration in African Spiny Mice (Acomys)." Nature 489 (2012): 561-65. doi:10.1038/nature11499

Gawriluk, Thomas R., Jennifer Simkin, Katherine L. Thompson, Shishir K. Biswas, Zak Clare-Salzler, John M. Kimani, Stephen G. Kiama, Jeramiah J. Smith, Vanessa O. Ezenwa & Ashley W. Seifert. "Comparative analysis of ear-hole closure identifies epimorphic regeneration as a discrete trait in mammals" Nature Communications 7.11164 (2016). doi:10.1038/ncomms11164

Monday, June 27, 2016

How to Become a Zoo Keeper

By Sara ‘Wesley’ Pederson

Photo provided by Bridget Walker.
Captive wildlife can be a notoriously difficult field to get into, and zoo keeping is a highly competitive career within that field. In order to determine what prepares one for a career in zoo keeping and makes them a desirable applicant, I interviewed some keepers from Henry Vilas Zoo in Madison, WI.

The first step to becoming an eligible candidate is to have an appropriate educational background. The most common route is to receive a Bachelor of Science degree in a biological science such zoology, biology, or ecology. It is also possible to obtain a B.S. degree in another major with a biology-related minor or emphasis, but this degree will need to be more heavily supplemented with animal-related experience. Another less common route that is gaining popularity is attending a vocational school or similar facility for an Associate degree. While these types of programs are great for saving time and money, they are highly specialized and may hinder your applicability for other positions in the future.

A degree alone isn’t enough to set you apart from other applicants though, your resumé must also be bolstered with ample skills and experience. Employment, extracurricular activities, and internships are all beneficial opportunities for building a strong resumé. Having a background in animal caretaking is also important; even things like owning pets or pet sitting, volunteering at your local shelter, cleaning kennels and stables, or working as a farmhand can offer you the experience you need to be comfortable in zoo settings. While animal-related experiences are the most directly related, it is also important to not discount seemingly unrelated jobs. It is imperative that you are adaptive, observant, have the ability to tolerate high levels of both physical and mental stress, and have good time management and interpersonal skills. Balancing a part-time job or extracurricular activities with your coursework can aid in the development of these skillsets necessary for such a strenuous and demanding career.

Once you have gotten a degree and started building your resumé, it is important to continuously develop your skills and begin networking. Don’t shy away from entry-level jobs or volunteering - These will get your foot in the door and show potential employers that you are capable and willing to do what needs to be done. Attending conferences and symposiums are a great way to keep up-to-date with the most recent findings in topics such as animal welfare and conservation while establishing professional contacts. Do your own research and pursue certifications to expand your knowledge and hands-on experience. Even long after you’ve secured a job, you’ll continue gaining experience to further your career.

While zoo keeping is a highly competitive career, it is possible to get a job with the proper qualifications. The first step towards securing a keeping position is to lay the groundwork with a college degree. Enhancing your degree and resumé with ample hands-on experiences and skills is the best way to set yourself apart from other applicants. While you are acquiring experience, do not disregard entry-level positions or jobs that seem unrelated or are less than ideal, these can often be the first step to jumpstarting your career.

Monday, June 20, 2016

Mosquitoes Don’t Like Parasites Either (A Guest Post)

By Maranda Cardiel

A photograph of Culex pipiens, the species of mosquito that the researchers used
in their experiment. Source: David Barillet-Portal at Wikimedia Commons.

Everybody hates mosquitoes. They are annoying, persistent, and make us itch like crazy. Sometimes there are so many of them that we are afraid to go outside unless we want to risk getting covered in spots and scratching ourselves all over for the next week. And if that wasn’t enough, they can also carry dangerous diseases with the potential to kill us. However, just like us, mosquitoes don’t like to be bugged by parasites that can make them sick either. Research shows that they may even avoid interacting with hosts that might pass along parasites to them.

A group of researchers - Fabrice Lalubin, Pierre Bize, Juan van Rooyen, and Philippe Christe from the University of Lausanne in Switzerland and Olivier Glaizot from the Lausanne Museum of Zoology – wanted to see if mosquitoes would show a preference for feasting upon birds that were infected with malaria (a blood parasite) or uninfected birds. Mosquitoes find animals to snack on by sensing odors and carbon dioxide in the air that animals give off, along with using their senses of vision, hearing, and touch. In order to figure out if mosquitoes use these senses to specifically choose their unlucky victims, the researchers did an experiment with mosquitoes, malaria, and great tits (a type of bird with a funny name).

For their experiment, the researchers collected mosquito eggs that they hatched and raised in a lab. Only female mosquitoes suck blood, so only female mosquitoes were used in the experiment. The mosquitoes had never been exposed to birds before and were starved of sugar for one day to make sure that they would be hungry. The researchers also caught wild adult great tits, and they took small blood samples from each bird to test for malaria before and after the experiment.

Next it was time to see if the mosquitoes would find some birds to be more appealing than others. A special Y-shaped wind tunnel allowed the mosquitoes to choose between the odors of two birds: one that was infected with the malaria parasite and one that was not. But don’t worry, the mosquitoes could not directly contact the birds. The researchers set up the lab so that it was completely dark to mimic the natural settings of when mosquitoes feed in the wild. This also meant that the mosquitoes were blind and could only choose a bird based on the chemicals in the air. Randomly-chosen pairs of birds and new mosquitoes were used for each round of the test.

A cartoon depicting the experiment setup. A hungry female mosquito hones in on the odors
of a healthy great tit and a great tit infected with malaria parasites. Source: Maranda Cardiel

The results of the study showed that the mosquitoes had a strong preference for birds that were not infected with the malaria parasite. This was true even when the researchers took into account the body sizes and sexes of the birds. Previous studies with different kinds of birds, mosquitoes, and malaria or malaria-like parasites have found similar results. The researchers think that this may be because the malaria parasite somehow causes changes in the chemical processes in the birds’ bodies that the mosquitoes can pick up on.

Infection with malaria might change what the birds smell like to the mosquitoes or how much carbon dioxide the birds give off. There is also evidence that birds who are more susceptible to malaria infections have a different odor than birds with stronger immune systems. But why should mosquitoes be picky and choose to bite healthy birds? They certainly don’t seem like they care whose blood they suck when they are swarming around us!

Previous research has shown that mosquitoes infected with malaria parasites have problems developing their eggs and can have trouble sucking up blood from their victims. Female mosquitoes use blood to nourish their eggs, so if they don’t drink as much blood, they will not be able to lay as many eggs. This means that female mosquitoes carrying malaria parasites are less likely to produce as many healthy offspring. Thus, it makes sense for female mosquitoes to want to avoid feeding on birds that are infected with malaria.

This probably has not changed your thoughts about mosquitoes. They are still a nuisance that we all squish - or at least attempt to squish - upon sight. It might be ironic, but mosquitoes don’t like to have parasites bothering them either. Even though we hate them, maybe now you can find some solace in mosquitoes finding you attractive. It might be a sign that you are actually healthier than your peers.


Source:

Lalubin, F., Bize, P., van Rooyen, J., Christe, P., & Glaizot, O. (2012). Potential evidence of parasite avoidance in an avian malarial vector Animal Behaviour, 84 (3), 539-545 DOI: 10.1016/j.anbehav.2012.06.004

Monday, June 13, 2016

The Best Dads in the Animal Kingdom

Paternal care is not nearly as common in the animal kingdom as maternal care, and for good biological reason. In most species, females produce fewer, larger, and costlier eggs than males do sperm. Therefore, it is usually beneficial to females to maximize the possible success of each one, sometimes by gestating them inside their own bodies (as mammals do), or incubating the eggs until they are ready to hatch (as birds do), or by providing prolonged protection, food and training until they are ready to take on the world for themselves. Males, on the other hand, are usually benefitted more by spending their time trying to mate with as many females as possible and avoiding the costs of parenting. But for some species, these costs and benefits of parenting are such that it pays for males to be good dads. Here are some of the best dads in the animal kingdom:

1. The Endurance Prize goes to the emperor penguin: Emperor penguins breed on the sea ice of Antarctica, the coldest place on Earth. After Mom lays her egg, her nutritional reserves are so depleted that she must return to the ocean (which can be over 100 miles away) to feed. This leaves the responsibility of keeping the egg warm through the freezing Antarctic winter to Dad. Dad goes months without feeding to balance the egg on his feet in subzero weather (-30 degrees Fahrenheit, on average) with freezing winds up to 120 mph, often forced to huddle together with other dads for warmth until their chicks hatch. If he moves too suddenly or the egg becomes exposed to the freezing temperatures, the chick will die. Even though he hasn’t eaten for months and has lost about 40% of his body weight, Dad provides the newly hatched chick with sustenance: a milky-type substance produced by a gland in his throat until Mom returns to the family with a belly-full of fish.

An Emperor penguin dad feeds his chick after a brutal winter without
eating a single bite himself. Photo by Mtpaley at Wikimedia Commons.

2. The Provider Prize goes to the water bug: Water bugs (also known as toe-biters) are huge, predatory, aquatic insects that can reach sizes up to 4 inches in length! They have a strong beak and a painful bite and they have been known to eat small fish, frogs and even birds! In order to grow into a large predatory insect, one must hatch from a large egg. Water bug eggs are so large that they require more oxygen for development than they can naturally absorb through the water. This requires a parent to help supply them with oxygen. However, Mom spends so much of her energy producing these humongous eggs that she doesn’t have enough energy reserves to then care for them. This leaves all of the parental duties up to Dad. In these species, Mom lays her eggs on Dad’s back in between matings. Once the full clutch of up to 150 eggs are glued to Dad’s back, he dances around and does underwater pushups to keep the water circulating and periodically takes them on a field trip to the surface for air (which has more oxygen that water does) until they hatch.

A water bug dad carries his eggs. Photo by Marshal Hedin at Wikimedia Commons.

3. The Protector Prize goes to the Darwin’s frog: Darwin’s frogs are small South American frogs that look a bit like a bloated leaf. When they mate, Mom lays her eggs in the leaf litter, which Dad fertilizes and then guards for a few weeks until the developing embryos begin to move. At that point, he “swallows” the eggs into a pouch near his throat called a vocal sac, where they hatch. He carries the tadpoles in his vocal sac until they have fully developed into frogs, at which point he “vomits” them up and they hop away to start their new lives. It’s pretty gross. Watch:


4. The Pregnancy Prize goes to the seahorse: Male seahorses have fewer (and thus more precious) sperm than males of other species and they are the only males that take on the full responsibility of pregnancy, carrying up to 2,000 babies at a time! Although they don’t have a mammalian womb and placenta, they do have an enclosed abdominal pouch specifically for the purpose of incubating the babies. Mom deposits her eggs in Dad’s brood pouch. He fertilizes them and incubates them in his expanding belly for 10-45 days (depending on the species). During this time, his body undergoes a number of hormonal and physiological changes and Mom never even makes an ice cream run for him or rubs his (non-existent) aching feet. When the babies are ready to emerge as fully developed little seahorses, seahorse dads even experience contractions as they give birth!


The best dad and grandpa in the world.
Photo by Sarah Jane Alger.
5. The Multi-Generational Prize goes to humans: Many human dads are not only good fathers, but also good grandfathers. Grandparenting is extremely rare in the animal kingdom (the first documented case of grandparenting in non-humans was as recent as 2008) and human males excel at it. They provide care, advice, lessons and resources to increase the success of their offspring and grand-offspring… It’s amazing other species haven’t picked up on this amazing secret yet!