Sunday, September 29, 2019

A Yawn & Man’s Best Friend

By Erin Gellings

There’s nothing quite like the feeling of coming home after a long hard day and being welcomed by your dog. Many things dogs do are in response to their owners’ actions, including comforting and mimicking actions like yawning. There are many theories about why humans and other animals yawn, but no one theory has been proven 100% correct. What causes dogs to yawn in response to seeing a human yawn though?

Yawning Dog. Image by Scientre from Wikimedia Commons

This was the question Silvia Karine and Bessa Joana from the Universidade do Porto in Portugal set out to examine. The researchers found preliminary evidence that simply the sound of a human yawn and their relationship with their owner is enough to make a dog yawn.

Sometimes, when dogs are under stress, they can do something called a ‘tension yawn.’ There is still little evidence that explains why dogs yawn when experiencing stress. The best way to know if a dog is yawning due to feeling stressed, or in response to a human is to look at the environment. If the dog is in a new setting with new people, it is likely yawning due to stress. Researchers were very careful to make sure all the yawns dogs produced were genuine and not stress related. This was partly achieved by allowing dogs to become used to researchers before being introduced to audio of yawns. They made this determination by carefully reviewing what events led up to the dog’s yawn.

Karine and Joana used 29 dogs of various breeds and let each one become acclimated to them by just sitting in the dog’s home for about 10 minutes before they started the experiment. The researchers then exposed them to four conditions: a prerecorded sound of their owner’s yawn, familiar control sounds from their home, a stranger’s yawn, or control sounds not from their home. Each dog experienced the prerecorded sounds in a random order during two different sessions. A researcher played the sounds through a large set of speakers from audio files from a laptop in the dog’s home. The researcher wrote down every time the dog yawned, and also made a video recording of the dogs listening to the sounds so other researchers could go back and double check that their count was correct.

Twelve of the twenty-nine dogs yawned during the experiment. Out of the dogs who yawned, more dogs yawned at the yawning audio than at the background audio. This leads us to believe that the sounds of yawning are contagious and the dogs “caught” the yawn. The researchers also found that dogs yawned more when listening to the yawn of their owners than of strangers.

Aside from showing that dogs tend to yawn after hearing a human yawn, this research also hints that there may be some sort of social variable in why dogs yawn more at their owner’s yawn. The researchers suggest this may be related to a sense of empathy dogs feel towards humans, but this claim needs more research in order to be demonstrated. This research also showed that dogs do not necessarily need a visual cue of seeing a person yawn in order to yawn on their own. This is a claim that is unique to this particular project. While this research is still in its early stages, it does give us a new perspective on why dogs may yawn when around humans, and what leads to this unique behavior.

Although this study does not help us understand the function of yawning in dogs, it does bring us closer to understanding why dogs yawn in response to humans and sets the stage for future research in the field. So, after your next long day when you sit down and yawn and notice your dog yawn too, take a moment to appreciate the connection they have with you.


Finlay, K. (2017, June 15). Why do dogs yawn? American Kennel Club.

Silva, K., Bessa, J., & De Sousa, L. (2012). Auditory contagious yawning in domestic dogs (Canis familiaris): First evidence for social modulation. Animal Cognition, 15(4), 721-724.

Why do I yawn? (2019).

Saturday, September 21, 2019

A Master of Disguise (A Guest Post)

By Jake Klemm

Cephalopods are among the most intelligent of marine life. Their highly advanced nervous systems allow them to exhibit a complex array of behaviors (for example, camouflage). Within this array is a rather unique behavior observed in the cuttlefish Sepia pharaonis. These elegant beings are now known to… intensely flap their arms? These animals are truly graceful.

A lovely photo of S. pharaonis. Image by Silke Baron at Wikimedia Commons.

Researchers Kohei Okamoto, Haruhiko Yasumuro, Akira Mori, and Yuzuru Ikeda of the University of the Ryukyus in Okinawa, Japan observed this behavior on two separate occasions while studying S. pharaonis. The scientists had initially collected these cuttlefish with the intention of conducting other experiments but noticed this behavior while the cuttlefish were introduced to a large water-filled tank and while hunting prey. After noticing this wild arm-flapping behavior, the researchers turned their attention towards why the behavior was being displayed.

The researchers first observed this behavior in December of 2011. The cuttlefish were placed in a large, circular tank for conducting other experiments when a couple of them were observed to flap their arms. After the initial experiments were finished, a few of the cuttlefish were placed in the same sized tank and observations were recorded with a video camera over a period of five days. This behavior was revisited in 2013 for further observation. The cuttlefish they used were reared from eggs found in the same coastal waters of Okinawajima Island as the cuttlefish that were part of the 2011 experiments. Again, cuttlefish were placed in a large tank to observe the behavior with a video camera. The researchers counted each occurrence of the behavior and recorded the duration of each behavior. After observations were complete, the researchers performed experiments to observe the hunting ability of S. pharaonis. This arm-flapping behavior was observed unexpectedly while the cuttlefish hunted prey. The means of recording the behavior were the same as described above. In addition, the researchers recorded the number of prey caught between cuttlefish that did and did not display the behavior.

The researchers noticed variation in the frequency and duration of this behavior in the presence and absence of prey. When placed in a tank without prey, only a small number of cuttlefishes displayed this behavior. Of the cuttlefish that did flap their arms, the behavior lasted (on average) no longer than 37 seconds. However, the cuttlefish that were placed in a tank with prey, the behavior was displayed for at significantly longer period of time. In addition to that, more cuttlefish overall were seen flapping their arms in this second experiment. The cuttlefish that flapped their arms caught a significantly larger number of fish than the ones that did not flap their arms, despite being observed in the same tank and having access to the same number of prey animals. This observation led the researchers to believe that something about this unique behavior is helping the cuttlefish capture more prey.

A front view of a cuttlefish. Image by Stickpen at Wikimedia Commons.

The resemblance is uncanny! Image by Maximilian Paradiz at Wikimedia Commons.

What could this all mean? The researchers think that the cuttlefish may be mimicking another organism, specifically the hermit crab, to confuse the prey fish into thinking that they are another harmless animal. It is thought that the head of the cuttlefish resembles the shell of the hermit crab while the arms resemble the eyes and legs of the hermit crab. Posing as a harmless crab would allow the cuttlefish to get behind enemy lines and ultimately catch more prey. Further research will have to be done in lab as well as the field to see if this behavior is really that of mimicry. Other cephalopods are notorious for mimicking other animals, so it is not out of the realm of possibility. Studying this behavior would allow scientists to difurtveher into the evolutionary history of S. pharaonis. Until then, the graceful limb-flailing will remain an ever-tantalizing mystery.


Okamoto, K., Yasumuro, H., Mori, A., & Ikeda, Y., (2017). Unique arm-flapping behavior of the pharaoh cuttlefish, Sepia pharaonic: putative mimicry of a hermit crab. Journal of Ethology, 35(3), 307-311. DOI: 10.1007/s10164-017-0519-7

Saturday, September 14, 2019

How To Get Into An Animal Behavior Graduate Program: An Outline

Do you dream about a career of studying animals?
Image by
A repost of an original article from March 13, 2013.

**NOTE: Although this advice is written for those interested in applying to graduate programs in animal behavior, it applies to most programs in the sciences.**

So you want to go to grad school to study animal behavior… Well join the club! It is a competitive world out there and this is an increasingly competitive field. But if every fiber of your being knows this is the path for you, then there is a way for you to follow that path. With hard work, dedication and persistence, you can join the ranks of today's animal biologists to pursue a career of trekking to wild places to study animals in their native habitats, testing questions about the physiology of behavior in a lab, or exploring the genetics of behavioral adaptation.

This is an outline of advice on how to get into a graduate program in animal behavior. More details on the individual steps will follow, so leave a comment below or e-mail me if you have any particular questions you would like me to address or if you have any advice you would like to share.

  1. Get good grades, particularly in your science and math courses. And make sure you take all the science and math prerequisites for biology graduate programs.
  2. Prepare well for the GREs.
  3. Get research experience. This can come in many forms (such as volunteering in a lab, working as a field technician, or doing an independent project for credit), but as a general rule, the more involved you are in a project, the more it will impress those making acceptance decisions.
  4. Choose the labs you are interested in, not just the schools. As a graduate student, you will spend most of your time working with your advisor and the other members of your advisor’s lab. This means that the right fit is imperative. Figure out what researchers you may want to work with, then see if they are at a school you would like to attend.
  5. Be organized in your application process. There will be a lot of details to keep straight: due dates, recommendation letters, essays, communication with potential advisors… The more organized you are, the less likely you are to miss a deadline or make an embarrassing mistake.
  6. Write compelling essays. Most schools will ask you to write two short essays: a Statement of Purpose and a Personal History. This is your place to set yourself apart. They need to convey your experience with animal behavior research and passion for working with that particular advisor. They also need to be very well written, so expect to write multiple drafts.
  7. Be organized and prepared when you ask for your recommendation letters. The easier you make it for your references to write a thoughtful recommendation letter for you, the better the letters will be.
  8. Apply for funding. This isn’t essential: Most first-year graduate students do not have their own funding. But the ability of a school and a specific researcher to accept a graduate student depends on what funding is available to support them. If you have your own funding, it is more likely you will to be able to write your own ticket.
  9. Be prepared for each interview you are invited to.
  10. If at first you don’t succeed, try and try again. Although heartbraking at the time, it is very common in animal behavior graduate programs to not be accepted anywhere in your first year of applications. If you are rejected, it doesn’t necessarily mean you are not a good candidate. Often it means there is no funding available to support you in the labs you would like to join. Spend the year participating in research and applying for funding so you can reapply next year.
The submission of a successful application takes a lot of planning and preparation. Getting good grades is a continuous effort. Plus, the most successful applicants often have two or more years of research experience. Ideally, you are working on these two things at least by your sophomore year of college. But if you waited too long and you haven’t taken enough science or math prerequisites, your grades are not where they need to be, or you don’t have enough research experience, you can take some extra time after you graduate to take community college courses and volunteer or work in a lab. Persistence and dedication are key to following a challenging path.

Sunday, September 8, 2019

Tiny Ninjas, Big Bites (A Guest Post)

By Alexis Brauner

Venom isn’t just a weapon for snakes and spiders.

A smaller, more dangerous insect is in existence and falls into the realm of venomous creatures: the assassin bug. This little critter is part of a scientific family called Reduviidae, a group where all the members share the same characteristic of being an ambush predatory bug. They prey on invertebrates (animals that don’t have a spine), such as crickets and mealworms, by injecting venom into them.

An assasin bug. Source: Fir0002/Flagstaffotos at Wikimedia Commons.

Assassin bugs are believed to have two versions of venom – one for feeding and one for defense. Both types of venom are made up of more than 100 proteins, but what is unique about it is its ability to paralyze and liquify the inside of the prey. That’s right… liquify. The tissues of the prey turn into a jello-like substance that the assassin bug can then suck through a long tube on its mouth called the proboscis.

How is the venom able to do that?

First, let’s peek at the mechanisms that work to carry the venom through the body of the assassin bug and into its meal.

The venom apparatus of an assassin bug is made up of three main parts: secretory glands, a muscle-driven pump, and a venom channel. The three secretory glands (the anterior main gland, posterior main gland, and accessory gland) are in the thorax and abdomen of the assassin bug. These separate glands release a specific form of assassin bug venom depending on what situation the bug is facing. For example, the anterior main gland releases a form of venom that does not paralyze prey but is thought to be used as a defense mechanism, while the posterior main gland releases the deadly form of venom.

The venom apparatus of an assassin bug. Source: Walker, et. al, 2018, modified by Alexis Brauner

Once released, the venom then makes its way to a muscle-driven pump within the head of the bug. The pump fills with the available venom when the muscle contracts and is released once the muscle relaxes. Think of the venom pump as a clothes pin: when you push on the prongs, the pin opens, and you can put things in it to hold; once you let go of the prongs, the mouth of the pin closes, but now the prong end is open. In this example, your fingers are the muscle and the clothes pin is the pump with one end open at a time. The muscle relaxation releases the venom into the venom channel in the interlocking maxillary stylets (also known as the fangs) of the assassin bug. And then…


Venom is in the food or the foe.

And if it’s in the food, then the tissues of the prey turn into liquid. This liquification phenomenon is caused by enzymes in assassin bug venom called proteases. All enzymes catalyze, or speed up, chemical reactions; however, proteases are specialized enzymes that catalyze the destruction of proteins. This means that the assassin bug venom goes into the prey and the proteases are like Pac-Men with razor sharp teeth that grind up the primarily protein tissue at such a lightning fast speed that, within seconds, the prey is juice!

Scientists continue to research assassin bug venom to learn more about its components, but one thing is for sure: The extraordinary liquid weapon housed in such a small insect is why assassin bugs are tiny ninjas with big bites.

To learn more:

Walker, A., Madio, B., Jin, J., Undheim, E., Fry, B., King, G. (2017). Melt With This Kiss: Paralyzing and Liquefying Venom of The Assassin Bug Pristhesancus plagipennis (Hemiptera: Reduviidae). Mol Cell Proteomics, 16 (4), 552-566. DOI: 10.1074/mcp.M116.063321.

Walker, A., Mayhew, M., Jin, J., Herzig, V., Undheim, E., Sombke, A., Fry, B., Meritt, D., King, F. (2018). The assassin bug Pristhesancus plagipennis produces two distinct venoms in separate gland lumens. Nat Commun, 9, 755. DOI: 10.1038/s41467-018-03091-5