Tuesday, February 21, 2017

Who Can Swim Further: A Race to the Depths and Back (A Guest Post)

By Jefferson Le

The blue whale (Balaenoptera musculus) is the largest mammal on the planet. Image by
NMFS Northeast Fisheries Science Center (NOAA) available at Wikimedia Commons.
Helloooooo! My name is Bailey and I am a 25 meter long blue whale, the largest living mammal on Earth! My friend Finley, a 21 meter long fin whale comes in second for largest in size. We had an interesting adventure recently where we were followed by humans. While Finley and I were foraging for food, I overheard the humans talking about investigating our diving behavior when we hunt and not hunt. With that, I will tell you what these foreigners did to investigate our behavior and also what happens when we dive.

A chart of whales of different sizes. Image by Smithsonian Institute.
To record our dives, the humans travelled to Mexican waters to attach recorders onto our mid-backs using a crossbow. Now, it didn’t hurt much due to my thick blubber. These devices recorded depth of how far we dived, time of dives, and our location. These recorders eventually came off between 5 to 13 hours later. Finley and I were not the only test subjects. Other members of our species were also tagged. After all the data on the devices were collected, the humans finally left our waters and did statistical analyses on our diving behavior.

The fin whale (Balaenoptera physalus) rarely exposes its fluke when it prepares to dive
to the abyss. Image by Aqqa Rosing-Asvid at Wikimedia Commons.
Now, before we talk about what the humans found, I want to share with you the whale secret to a great dive. In case that you ever find yourself in the ocean or your local pool, you can try it! The nose for Finley and I are called blowholes, which are found on top of our heads. This tract is separated from our digestive tract so we do not have to worry about having food go down our blowhole. When I am about to dive, instead of gulping in lots of oxygen, I exhale out as much as I can. This causes my lungs to collapse and flexible walls in my chest allow even more compression. Also, tiny structures in my lungs called alveoli collapse which halts any gas exchange. All of the decrease in lung space decreases buoyancy so I can descend down to the depths.

As I descend, my heart rate lessens to reduce energy used during the dive. The oxygen that I had obtained before the dive is stored in my blood and muscle tissue. Since the deep depths are really cold, blood flow is temporarily halted at the thinner areas of my body, like flippers, and some organs to keep the main body going. When I ascend back up, I gradually increase space in my lungs and my alveoli regain full function to allow gas exchange. If you were to ascend too quickly, you could get shallow water blackout or even worse, the “bends” (where nitrogen bubbles in your blood) and I heard it is painful. After ascending is complete, I can release my blowhole open and take in fresh oxygen again.

I was secretly told what the results to the humans’ experiments were. They found out that fin and blue whales dove deeper when hunting on shallow dives when not hunting. It makes sense! Why spend so much energy diving when not hunting? Also, they noted that our lunge feeding frequency was different. Lunge feeding is where we propel ourselves towards our prey with our mouth open and grab as much food as we can into our mouth. Blue whales lunged about 2.5 times more than fin whales! That’s a point for the blue! However, the record dive depth came from a fin whale. Hmm… I wonder if Finley broke that record.

Did you find my secret and what the humans found interesting? I surely did. I never thought about how I dive and how I behave as it is practically in my blood! Well, the next time you are at a deep pool, try those secrets I spilled to you. It might be fun! Then again, you might be thinking, how does a whale communicate with a human and understand scientific data? That is a secret you may never know…

Literature Cited:

Croll DA, Acevedo-Gutiérrez A, Tershy BR, & Urbán-Ramírez J (2001). The diving behavior of blue and fin whales: is dive duration shorter than expected based on oxygen stores? Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, 129 (4), 797-809 PMID: 11440866

Hill, R. W., G. A., Wyse, M. Anderson. (2008). Animal Physiology. 2:641-660

Tuesday, February 14, 2017

The Complexities of “The Love Hormone”

New York street art. Photo in
Wikimedia Commons posted by Pedroalmovar.
Oxytocin, commonly known as “the love hormone”, is a small chemical that is produced in the brain of mammals, but can both act as a neurotransmitter and enter the blood stream and act as a hormone. It has long been heralded for its role in both maternal and romantic love, but more recent research is showing us just how complicated the physiology of love can be.

Oxytocin is released in mammalian mothers after birth. It promotes nursing and bonding between a mother and her young. As children grow, oxytocin is involved in how both mothers and fathers “baby-talk” and mirror their children. It is involved in pro-social behaviors in both young and adults: trust, generosity, cooperation, hugging, and empathy. And of course, oxytocin promotes positive communication and pair bonding in romantic couples. Countless studies have found these relationships between affiliation and oxytocin in many mammalian species, giving oxytocin its commonly used nickname “the love hormone”.

But more recent studies show that it’s not so simple.

In a number of recent studies, people have been given oxytocin nasal sprays and tested for various behavioral effects in different contexts… and the context really seems to matter. Oxytocin increases trust, generosity, cooperation, and empathy towards people we already know and like. But it decreases trust, generosity, cooperation, and empathy towards strangers. When we play games with strangers, oxytocin makes us more jealous when we lose and it makes us gloat more when we win. It also seems to enhance many attributes relating to ethnocentrism: It increases our ability to read facially-expressed emotions in people of our own race while making it harder to read facial expressions of people of a different race. When forced to choose between being nice to a stranger of our own race versus a stranger of another race, oxytocin makes us more likely to choose the person of our own race. In studies of both people and rodents, oxytocin decreases aggression towards our families and friends, but increases aggression towards strangers.

Oxytocin is not the universal love hormone we once understood it to be. It helps us direct our positive support towards our “in-groups” (our family and friends) and defend them from our “out-groups” (individuals we don’t know). It is a delicate balance: Too little of it can cause social impairment and make it difficult to connect with loved-ones; Too much of it can increase our anxiety towards strangers and racist tendencies. And to make things more complicated, each of us has a slightly different oxytocin system: sex, gender, social history, history of childhood trauma or neglect, psychiatric illnesses and genetic variations all have profound effects on the oxytocin system.

There is much we don’t know about the role of oxytocin and love. But they are a good fit, because both, it seems, are complicated.

Want to know more? Check these out:

Shamay-Tsoory SG, & Abu-Akel A (2016). The Social Salience Hypothesis of Oxytocin. Biological psychiatry, 79 (3), 194-202 PMID: 26321019

Zik JB, & Roberts DL (2015). The many faces of oxytocin: implications for psychiatry. Psychiatry research, 226 (1), 31-7 PMID: 25619431

Tuesday, February 7, 2017

How to Get into Veterinary School: The General Application Process

By Mary Harman

Is this where you want to be?
Photo by Elizabeth Martens.
The field of veterinary medicine is not only a profession that has been around for centuries, but is one that remains respectable and ever-expanding in the modern world. However, the field also remains a highly competitive one; according to the AAVMC (Association of American Veterinary Medical Colleges) there are 30 accredited veterinary colleges in the United States and each one only accepts, on average, 80-100 students a year. There are also 25 accredited veterinary colleges outside of the United States if studying abroad is more your style. A full list of accredited vet schools is available on the AAVMC website. So, while a passion for animals and their care is indeed important to becoming a veterinarian, more aspects must be taken into account when looking into the field of veterinary medicine: the cost, work, applications, grades, and most importantly: reward. But if you’ve decided that you are willing to jump into this world, then there are a few things you need to do before you start applying.

The application process for vet school tends to be quite lengthy, and it is highly recommended that you begin this process long before the application deadlines. Most of the accredited veterinary colleges in the US and many outside the US require the completion of a Veterinary Medical College Application Service (VMCAS) application. This application is essentially a single, secure, online copy of your vet school application that can be distributed by AAVMC to your desired schools electronically. The goal is to allow you to keep all of your shadowing hours, courses taken, GPA, and personal information in one convenient location. Note that there is a fee associated with submitting your VMCAS application that is based on the number of schools you are applying to, and a strict VMCAS deadline each year (to learn more about the VMCAS: check out “VMCAS- In Depth!”-coming soon, or VMCAS FAQs).

One important thing to note is that you do not, and I emphasize the not, need a bachelor’s or even an associate’s degree to apply to veterinary school. However, there is often a list of college classes and credits that you need to complete before applying (see The Academic Phase, below). Since most veterinary schools require similar courses, they will also follow a similar application process that is designed to pick out the best applicants. These processes often involve at least three steps, or phases. Each one is important, but some colleges may lean more heavily on one of the three when making the final decision.

The Academic Phase

The Academic Phase is where the admissions staff look at your grades and all of the academic aspects of your application. They glance over the courses that you have taken to see if you have fulfilled the set of requirements they believe are important. In general, most vet schools require a minimum amount of English, math, and social science credits. They will also require general biology classes, including genetics, some form of animal biology or zoology, and several upper level biology classes (often including physiology, microbiology, and anatomy). Every school is different on the exact specifications of the classes they expect, so you should research the requirements for any school you are considering applying to. A List of course requirements for each AAVMC accredited school can be found here.

Getting into vet school requires lots of this.
Photo by Mary Harman.
The admissions staff also look at your cumulative GPA, and some schools will look at your science GPA and/or your GPA of your last 45 credits. Most veterinary colleges list the minimum GPA needed to apply as somewhere between 2.75 and 3.0; however, most have a competitive GPA between 3.5 and 3.75. That means that during senior and junior year, you need to work just as hard to maintain your grades as any other semester: No senioritis allowed (okay maybe a little, but that depends on the classes you are taking).

For studying advice, read this.

This is also where they look at your GRE composite score, but some schools will look at the individual sections as well. The GRE, or Graduate Record Examinations, is a standardized test that consists of three sections: Verbal Reasoning, Quantitative Reasoning, and Analytical Writing. The GRE is completely computerized and lasts about 4 hours. This test must be taken and sent to your preferred schools before you send in your applications. For many veterinary colleges, a competitive GRE composite score for admittance is above 300 out of a possible 346.

The Personal Phase

It is important to get a range of animal experience.
Photo by Mary Harman.
The Personal Phase is the section on the application where you will talk about yourself. This section often starts with a personal statement. The personal statement is basically where you explain why you want to go to vet school and why you think you have what it takes. This section is also where you include all the animal experience and veterinary experience you have obtained going all the way back through high school. There is no minimum number of hours of experience that is required for vet school, however most applicants have at least 500 hours.

Some schools will differentiate between animal experience and vet experience, so keep that in mind when you are applying to schools, and when you are obtaining your shadowing hours, internship and work hours, and volunteer opportunities. All of these areas count towards your experience one way or another. It is extremely important to try and work with a variety of animals, clinics, and vets to help your application stand out among the mountainous stacks of applications that the veterinary colleges receive.

Many veterinary colleges require that you shadow more than one vet in a certain discipline, and in other areas of the practice to make your application well-rounded; however, the general rule is that most of your shadowing hours should be with vets in the certain discipline you want to work in once you graduate. For example, if you wish to work in a small animal clinic after you graduate the majority of your hours shadowing should be with small animal vets. Keep in mind though, when you are in vet school you will be learning about and working with several different species.

Another benefit of shadowing is forming a professional relationship with the doctors, which can come in handy for obtaining your letters of recommendation, and also once you graduate and are searching for a job. The letters of recommendation are required for vet school, and most schools require three letters. The letters do not all have to be from veterinarians, but most prefer at least one letter of recommendation from a veterinarian. This generally nerve-racking task can be made slightly easier if you have already established a relationship with a vet that you have been shadowing or working with.

The Interview Phase

The interview phase is the most exciting, and probably the most nerve-racking, phase of the whole process. It often signals that out of all the applications received (some of the larger schools receive over 800 applications a year) the administrative members were impressed by yours, and would like to interview you personally. This is generally a good sign. For most schools a good interview can have a huge influence on your acceptance; good interview skills and be a major advantage in such a competitive process. If your undergraduate college offers a seminar on interview etiquette, it may be in your best interest to attend at least one. This way you can be prepared for your interview, and hopefully feel a little less nervous.

Another piece of advice, as you consider veterinary medicine, is that many prospective veterinary students find it helpful to go and visit their schools of interest. Don’t be shy about reaching out to the admissions directors about taking a tour of the facilities. Many veterinary colleges offer days that are strictly designed for interested students to go and get a tour of the school. These tour days usually are led by a student currently in the program, at least for a portion of the day, and most of them are super open about answering any questions you may have (after all, they were once in your shoes too).

The processes and preparations needed to get accepted to vet school requires an enormous amount of dedication and commitment to education (but it is possible I promise); you must be willing and eager to pursue shadowing hours, internships, and jobs, on your own. However, if you are willing to put in the work and the time required the reward is great. Some day you will get to go home from work with the knowledge that you are saving numerous animals’ lives, easing their pain and illness, and creating a sense of peace for the owners who call them family.


AAVMC website, FAQ’s

VMCAS FAQ’s and Instructions


For more advice on careers with animals, check this out.

Tuesday, January 31, 2017

How to Get Animal Experience

Who wouldn't want to do this??
Photo provided by Bridget Walker.
Many of us grow up dreaming of someday becoming a veterinarian or animal trainer or zoo keeper. We raise pets and try to save the baby animals we find in the yard. We work hard in school and are mesmerized by Animal Planet. But what does it really take to make it into one of these coveted fields? A key factor to being competitive in any of these jobs is having lots of experience working with animals in lots of different ways. But there is a catch: to get a position working with animals, you need to have experience working with animals. So how are you supposed to get your foot in the door?

Snuggles! Photo by Jenna Buley.
The most reliable way to get animal experience is to volunteer, since most paid positions that work with animals are out of reach for those that do not have significant animal-handling experience. There are many different places that need volunteers to help with animal care. Local pet shelters, such as the Humane Society, are always looking for volunteers. For large animal experience, stables and animal farm sanctuaries are often looking for help. If you are looking for wildlife experience, many local wildlife rehabilitation centers and zoos will also accept volunteers. And if you are the adventurous type, there are ecotourism groups that can connect you with wildlife sanctuaries abroad that are looking for temporary volunteers (some are even geared towards pre-vet students). Granted, these volunteer positions are not glamorous: they don’t pay, they are hard work, and they generally involve cleaning lots of poop. But generally, the more you do, the more you will be allowed to do. And if you commit to at least 6 months to a year, you will make yourself competitive for other positions that work with animals.

Awww... as tempting as it is to pick up an adorable baby skunk,
don't do it unless you are a trained and licensed wildlife rehabilitator
(like this woman is). Image by AnimalPhotos at Wikimedia.
If you already have some animal experience under your belt, you may want to apply for some paid positions that work with animals. Zoos, aquariums, sanctuaries, and rehabilitation centers frequently have paid internships. Animal hospitals hire veterinary assistants, animal caretakers and receptionists with little to no animal experience. Stables and farms hire staff to care for their animals as well. In all of these cases, the larger and more famous the institution, the more competitive the applications will be and the more experience you will need to get a paid position.

Once your foot is in the door, you can move up the ranks into more exciting and fulfilling positions. Keep in mind that employers and veterinary schools are looking for both breadth and depth when it comes to animal experience. Having experiences at a variety of different places with a range of species will make you more competitive. Also, you want to stay in the same place for a long time (months to years) to gain the depth of animal-handling knowledge that employers and vet schools are looking for. But, if this is the career path for you, you may not want to leave anyway.

For more advice on working with animals, check this out.

Sunday, January 22, 2017

Nature Shapes Faithful and Unfaithful Brains

Among monogamous animals, some individuals are more faithful than others. Could these differences in fidelity be, in part, because of differences in our brains? And if so, why does this diversity in brain and behavior exist?

A snuggly prairie vole family. Photo from theNerdPatrol at Wikimedia Commons.

Prairie voles are small North American rodents that form monogamous pair bonds, share parental duties, and defend their homes. Although prairie voles form monogamous pairs, that does not mean they are sexually exclusive. About a quarter of prairie vole pups are conceived outside of their parents’ union.

Not all male prairie voles cheat on their partners at the same rates. In fact, some males are very sexually faithful. It turns out, there are both costs and benefits to being faithful and to cheating. Mariam Okhovat, Alejandro Berrio, Gerard Wallace, and Steve Phelps from the University of Texas at Austin, and Alex Ophir from Cornell University used radio-telemetry to track male prairie voles for several weeks to explore what some of these costs and benefits might be. Compared to males that only sired offspring with their own partner, unfaithful males had larger home ranges, intruded on more territories of other individuals, and encountered females more often. However, these unfaithful males were also more likely to be cheated on when they were away (probably because they were away more). I guess even rodents live by The Golden Rule.

Maps of how paired male voles in this study used space. The solid red/orange/yellow peaks show where a faithful male (in the left map) and unfaithful male (in the right map) spent their time in relation to where other paired males spent their time (showed by open blue peaks). Image from the Okhovat et al. Science paper (2015).

Vasopressin is a hormone that has been found to affect social behaviors such as aggression and pair bonding when it acts in the brain. Mariam, Alejandro, Gerard, Alex, and Steve all set out to determine how vasopressin in the brain may relate to sexual fidelity in prairie voles. They found that faithful males had lots of a particular type of vasopressin receptor (called V1aR) in certain brain areas involved in spatial memory. Surprisingly, faithful males did not have more V1aR in brain regions typically associated with pair bonding and aggression. A male that has more V1aR in spatial memory regions might better remember where his own mate is and where other males have been aggressive, which would decrease the chances that he would intrude on other territories in search of other females and increase the time that he spends home with his own mate. A male that has less V1aR in spatial memory regions might be less likely to learn from his negative experiences and more likely to sleep around.

Photos of a brain section from a faithful male (left) and unfaithful male (right). The dark shading shows the density of V1aR vasopressin receptors. The arrows show the location of the retrosplenial cortex (RSC), a brain area involved in spatial memory. Faithful males had significantly more V1aR receptors in the RSC compared to unfaithful males. Image from the Okhovat et al. Science paper (2015).

The research team then found genotype variations that related to having lots or not much V1aR in one of these spatial memory regions (called retrosplenial cortex … but we’ll just call it RSC). They confirmed these findings with a breeding study, in which they reared siblings that were genetically similar, but some had the genotype they predicted would result in lots of V1aR in RSC and some had the genotype they predicted would result in very little V1aR in RSC. They confirmed that these genetic variations correspond with the amount of vasopressin receptor in this specific spatial memory area.

The researchers then looked closer at the different versions of this vasopressin receptor gene in the RSC brain region to see if differences in the amount of vasopressin receptors in RSC may be caused by the epigenetic state of the gene (i.e. how active the gene is). They found that the genotype that results in very little V1aR in RSC had many more potential methylation sites, which can repress gene activity.

All of this data together tells a very interesting story. Male prairie voles that have the genotype for more V1aR vasopressin receptors in their RSC part of their brain are more likely to remember where their home and mate are and to remember where other aggressive prairie voles are, which will make them more likely to spend more time with their partner, to be sexually faithful and to have sexually faithful partners. Male prairie voles that have the genotype for less V1aR in their RSC are more likely to forget where their home and mate are and where other aggressive prairie voles are, which will make them more likely to cheat and to be cheated on. Overall, faithful and unfaithful male prairie voles have roughly the same number of offspring, but advantages may emerge with changes in population density. Prairie vole populations vary anywhere from 25 to 600 voles per hectare from year to year. When population densities are high, you (and your partner) are more likely to encounter more potential mates and it may benefit you to cheat (and have a “cheater’s brain”). When population densities are low, you (and your partner) are less likely to encounter more potential mates and it may benefit you to be faithful (and have a “faithful brain”). But when populations fluctuate between high and low densities, both faithful and unfaithful genotypes will get passed along from generation to generation.

Want to know more? Check this out:

Okhovat, M., Berrio, A., Wallace, G., Ophir, A., & Phelps, S. (2015). Sexual fidelity trade-offs promote regulatory variation in the prairie vole brain Science, 350 (6266), 1371-1374 DOI: 10.1126/science.aac5791