The jaw and teeth of hyena not only gives us insight into its powerful abilities but also gives clues to its ranking within the clan. During a darting one of things we do are dental measurements. We also look for broken or missing teeth during this process. One of the measurements we take is called the occlusal surface. We take this measurement from the PM3 (premolar teeth located between the canine and molar). This surface is the portion of the tooth that receives contact. Low ranking hyenas have larger occlusal surfaces than higher rankers. Lower rankers are more likely to feed on the bones of animals instead of meat and other organs. Since they have a tougher meal to chew their teeth become worn down much more quickly. A powerful jaw is a handy tool when it comes to extracting marrow from the bones of prey.
Monday, September 29, 2014
Posted by Ashlei Tinsley at 12:01 PM
JAWS! I bet the first thing that comes to mind when you hear JAWS is not the spotted hyena but the great white shark. Stephen Spielberg made the jaw of the great white shark the trending topic of the summer of his blockbuster release. While the great white shark has a mouth that is a force to be reckoned with, the spotted hyena also holds its ground in the ferocious jaw category. Hyenas may be smaller in stature compared to the other carnivores of the animal kingdom but what they lack in size they make up for with a powerful bite!
Hyenas have colossal jaw muscles. These jaw muscles produce about 9,000 Newtons of bite force. A hyena can possess a bite force 40% stronger than a leopard. Hyenas also have the ability to crack through bones of varying degrees of thickness. Our researchers here at Fisi camp have witnessed these bone crushing jaws in action.
Hyenas are skilled hunters who not only take down preys much larger than themselves but also eat a tremendous amount in a short period of time. Hyenas take down over 90% of the food they eat. We often see many of our hyenas leaving carcass sessions obese.
JUBA, a Talek West hyena demonstrates the power of his jaw on a wildebeest.
RSWL, a Talek West male hyena giving us his best smile :). Notice the broken teeth and cavities!
Keep visiting the blog for more updates and information about your favorite hyenas!
Friday, September 26, 2014
Posted by Maggie Sawdy at 9:42 AM
We found the North den!! About six weeks ago I posted a blog about all the Serena dens (August 11th).
At the time of my last post, our North clan had been denning in a cave. Really cool but really hard to get to (as in impossible!)! A couple of weeks ago we noticed the GPS points for one of our collared moms were way out in the marsh, almost at the border of the territory. (We download GPS points from our collared hyenas each day.) We went to investigate and found that this mom plus all the other North moms had moved their cubs to a new den. YES!!!
The new den presents a set of new and exciting challenges! The marsh part… The den is in an area that we cannot get to when it rains. After it rains, it can take a few days to dry out. There are also lots of holes, so it is not a great place to be driving when it is dark, unless you want to get stuck!
But, the most pressing challenge is that we don’t know the cubs! We need to be able to id them in order to get good data, but we have not seen them since late June. Trying to match pictures from then and now is difficult. Most of the cubs were still black then or were just getting their spots. However, we have managed to pick out three cubs: Kath (Kathleen Hanna), Rocket (Rocket Scientist), and Mim (Man in the Mirror). We still have two mystery cubs! These two are probably Deni (Dennis the Menace), Remi (Remington), or Jett (Joan Jett). Deni, Remi, and Jett were still black cubs when we last saw them so we don’t have any pictures of them. All three are from different moms, so we will have to watch who these mystery cubs nurse from to figure out who they are.
To begin sorting out the cubs, we tried to get a picture of each side of every cub. The goal of this was to be able to tell the cubs apart even if we hadn’t been able to match them to their official names yet. This method helped us sort out Kath, Rocket, and Mim. Now, taking pictures of both sides of the same cub is way harder than it may sound! The cubs just want to play, and they are constantly bouncing around and going in and out of tall grass. It is too bad that we cannot convince them to stand on a mound and stand still so that we can get a picture of one side and then the other! We would give them a lot if they were willing to do this!
This is what most of my pictures look like... Sigh!
Also since June, the cubs have grown and gotten fluffy which makes it harder to see their spots and match the photos.
This is what most of my pictures look like... Sigh!
Also since June, the cubs have grown and gotten fluffy which makes it harder to see their spots and match the photos.
For example, this is Kath in June:
This is Kath soon after we found the den.
To id him, we matched the three spots that are in a curve on his hindquarter’s above a larger dot and the curve of dots on his side.
Now that we know three of the cubs I am really excited to figure out the two mystery cubs. This will probably take some time, so for now I am just enjoying having a den again!
Wednesday, September 24, 2014
Posted by Molly McEntee at 1:40 PM
|Wildebeest crossing the river in our South clan territory|
The other night at the South clan den, while I was trying to record Slinky and Marten interacting with their cubs, I ended up recording a herd of gnu that were grazing nearby and drowning out the vocalizing moms. Near the end of the clip you can barely hear Slinky groaning into the den to call her cub out of the den over the gnu grunts.
|A wildebeest herd from the air|
Monday, September 22, 2014
Posted by Tracy at 2:56 PM
Hello all! My name is Tracy Montgomery, and I was a research assistant in Talek Camp three years ago. Now I’m lucky enough to be back as a graduate student! I study hormones and behavior in spotted hyenas and am especially interested in dispersing males and what allows them to be successful.
Many of the hyenas I knew back then have disappeared, dispersed, or died, but many are still here, eating and sleeping with the rest of Talek clan. The biggest (and best!) surprise for me was seeing Twister, who was an aggressive little black cub when I left, sacked out by the den nursing her own small cubs.
|At three months old, Twister was already aggressing on older cubs |
at the communal den.
Photo by Aurelia DeNasha
|Twister sacked out against her older sister, Parcheesi, in late 2011.|
Photo by Eli Strauss
Friday, September 19, 2014
Posted by Tracy at 4:28 PM
Hey folks! My name is Eli, I’m a 3rd year PhD student and a recent arriver in Fisi camp (I'm writing under Tracy's name until I get access as an official poster). It isn’t my first time in here in the Mara; I worked as an RA in Talek during 2011-2012, and I must shamefully admit that I didn’t do much blogging during that year. This year I promise I will do better! I’m incredibly excited to be back in the Mara and to get a chance to experience both sides of the park more fully over the next year. My plan is to spend time in both Talek and Serena camps doing a few experiments looking at social behavior in adults and cubs of different clans.
I regret to inform you that today’s post will not be about hyenas (bad start, right?). Those of you who are long-term readers of the blog may recognize this, however:
These are two stuffed lions on loan to us from Craig Packer’s lion research lab out of the University of Minnesota. With these lions, Packer and his student Peyton West investigated hypotheses concerning the function of the iconic mane of male lions. The most widely held hypothesis about the function of the lion’s mane was that it protects males from neck injuries during aggressive interactions. West and Packer found, however, that injuries to the neck area were not more frequent than injuries to other areas, and neck injuries were also no more likely to be fatal than other injuries. These findings suggest that the mane isn’t functioning as a shield. If it were, it would protect a highly targeted or vulnerable area!
|Packer's dummies outfitted with variously colored |
and sized manes. Photo from the Packer lab.
West and Packer next investigated the hypothesis that the lion’s mane is a trait that signals a male's quality. To do this, they acquired life sized stuffed lions with removable manes. They presented dummy males with different manes to real male and female lions and found that both sexes responded quite differently depending on the size and color of the lion dummy’s mane. Males were more likely to approach males with shorter and blonder manes, suggesting that they found them less threatening. Likewise, females were more likely to approach males with dark manes, suggesting that they found the more attractive. The findings support the conclusion that the mane is less of a shield and more of a signal of male quality. Pretty cool! If you are interested in reading more about these experiments check out their paper in Science in which they discuss the how climate change could affect mane size and color and its function as a sexual signal.
Here a male lion cautiously approaches one of the dummies in Packer and West’s experiment on mane function. From supporting materials of “Sexual Selection, Temperature, and the Lion’s Mane” published in Science in August 2002.
These lions should look familiar to some of you because in 2012 we briefly borrowed the lions to try out some experiments in which we were looking at the coordinated mobbing behavior hyenas display when they cooperate to fight with lions over control of a carcass. Kay wrote a blog post about these set of experiments, but the short version of the story is that we saw some pretty interesting stuff but none of the intense mobbing behavior we were hoping to observe.
|Hyenas from the Talek clan warily approach the dummies |
during the mobbing experiments conducted in 2012.
Photo taken by Steph Dloniak.
Now we have borrowed the lions again to do some related experiments, which Tracy, Kenna and I will be collaborating on over the next year. We will investigate the conditions under which different hyenas either decide to recruit help in fighting with lions over a carcass or instead choose to sneakily steal some of the food all on their own. Stay tuned for updates on how it goes, but for now enjoy some photos of the old girl in action!
Wednesday, September 17, 2014
Posted by Chase O'Neil at 10:19 AM
Jambo! My name is Chase and I’m the newest RA situated at the beautiful Talek camp. As I’m sure you can gather from reading these blog entries, there is a lot to learn out here in Fisi camp. However, there are some natural processes that everyone can recognize.
One such activity is waste excretion. Also known as pooping. Prepare yourself for a digestion digression.
When I first arrived I was presented with a new area to do my personal business, known to us lovingly as “The Choo” (Pronounced: Cho). The hyenas we study, on the other hand, use a large plot of land known as the Mara. It is a vital part of our job, when recording observations on aggressions, to also be aware of when a hyena has to excrete some fecal matter.
|The infamous Choo|
Why does the matter matter to us?
|Kenna Lehman sporting a hefty poop bag and a can-do attitude!|
Although poop can be used to analyze DNA and determine paternity for cubs, back at the lab they also look at hormones. The amount of a hormone in an individual’s excrement represents the level in the body. In fact, one intrepid researcher Sarah Jones uses poop to look at the hormonal basis of sex reversal in hyenas. So, why are females more aggressive and socially dominant to male hyenas? (Future Dr.) Jones looks specifically at the hormone androstenedione, which can act similarly to testosterone, but doesn’t usually have the same side effects that would be bad for females (reducing fertility or parental care.) In fact, female spotted hyenas exhibit higher levels than males till they’re at least five years old! The largest difference between sexes is actually when they are born, suggesting why most females assert dominance over their brothers at a very early age. Jones is looking at whether androstenedione concentrations in poop are related to female aggressive behavior and their rank. Do higher ranked, more aggressive females have higher levels of androstenedione? Stay tuned for that dissertation!
|Wilson Kilong thinks poop is just the best thing.|
|Two poops in one obs session? It's my lucky day!|
Additionally, Tracy Montgomery examines poop with a passion. She’s curious about male dispersal and what hormones play a role in that process. Adult natal males actually have lower testosterone than immigrant males, even though both are reproductively mature. Why might that be? What hormonal changes occur during the dispersal process? But, Montgomery doesn’t stop there. She’s also looking at the hormone progesterone and how it may be associated with affiliative and cooperative behavior.
|Ashlei Tinsley handling hyena excrement with class.|
But, I’m sure you’re asking yourself, “How can I do this at home? I want to analyze my bowel movements!”
Here is my advice:
1. A keen eye is important. When we see a hyena get into that well-known position (the squat) we use our binoculars to assess whether the bomb has been dropped or if it is simply urination. Once we decide the poop is indeed a poop, we drive over and scoop it up using a plastic bag (a large one if you’re lucky.) On the bag, we write the time it was collected, the location, and which hyena did the deed.
|Chase O'Neil, aka expert poop collector, does her job.|
|We see a variety of colors like above: pale banana cream pie.|
|A typical sample complete with white hairs from a tasty wildebeest dinner. But look, your expert eyes are right! BONUS: there are worms.|
|Foot-smashing time! Socks with sandals recommended.|
|A researcher with steady hands shoves pieces of the droppings into a tube.|
|This is known as the icing technique. Sometimes a hyena has a soupy poop (hey, we've all been there.) In this case, we cut a hole in the bag and squeeze out the future data. Just like icing a cake.|
So far, I have been lucky enough to see many hyena feces and participate in the collection. Everyday is an adventure here, but even more so when we have to scoop poop into tubes!
If you have a lab at home to analyze your poop, Julie did a wonderfully detailed post about poop processing in the lab that will give you step-by-step instructions (http://msuhyenas.blogspot.com/2012/07/what-do-we-do-with-all-this-poop.html
Monday, September 15, 2014
Posted by Sarah Jones at 1:35 PM
We recently confirmed that Polar, one of our Serena hyenas, has had a cub! As far as we know, this is Polar’s first cub (or at least it’s the first that has survived long enough for us to see it). It is looking very healthy, and Polar is a very attentive mother.
Prepare yourself for adorable photos:
|Polar's baby poking its head out of the den|
|Polar getting her cub out of the den so it can nurse|
The first time Molly and I saw Polar’s cub was pretty amusing. We had Polar at the den hole, and a black cub emerged from the den and appeared to be trying to nurse. Polar seemed rather irritated with the cub and would kick it off a nursing position with her hind leg. She finally got so annoyed that she tried to bite it. Molly and I were aghast at Polar’s lack of mothering skills and figured we shouldn’t get too attached to this obviously doomed cub. But lo and behold, a second, smaller black cub popped out of the den hole and started climbing all over Polar. She tolerated this with aplomb, and we later confirmed this was fact Polar’s cub when we saw it nurse. We later realized Polar was sharing her den with another mom, Diggory, and Diggory’s baby had been trying to nurse from Polar. It is not actually uncommon for cubs to try and nurse from the wrong mother, but they are usually quickly told off.
|Polar telling Diggory's cub off|
|Polar putting up with her own pain in the butt cub|
Diggory and Polar are keeping their cubs miles away from the communal den, where the older cubs hang out. Moms keep their babies in dens isolated from the rest of the clan while they are still very young. Diggory and Polar are both very protective of this den hole, so woe to any lower ranking hyena who wants to come say hi to the babies. In fact I’ve even seen Diggory chase and snap at Lady, a higher ranking hyena, because he dared to come within 5 meters of her den hole.
|Polar chasing off some big cubs from the den hole|
You might think these ladies are over-reactive bullies who terrorize anyone in the vicinity of the den hole. However, female hyenas have a very good reason to be defensive. Young cubs are easily killed by predators and adult hyenas of either sex.
On the other hand, this still doesn’t explain why Polar was so grumpy when a hungry cub tried to sneak some milk.
Hyena mothers have good reason to try and hoard resources for their own cub. The skull and jaw muscles of a young hyena take a particularly long time to develop compared to other mammals. This is because they need to develop the unique ability to crush bones. During this time of development, which lasts about three years, hyenas can’t eat their normal food very quickly. When you’re competing with clan-mates, which can devour an entire wildebeest in 15 minutes, this could be a serious liability (I grew up in a human family of four, and I’m still not sure how I survived being the slowest eater). Moms play an important role in ensuring their slow-feeding cubs get enough to eat in two ways: 1) Moms aggressively displace other hyenas at carcasses so their precious baby has time to feed. 2) Moms nurse cubs for prolonged periods of time, up to 2 years. Therefore, cubs rely on mom heavily for all their food for a long period of time. So yes, hyena moms have particularly good reason to be grumpy with anyone trying to steal food from their cub.
So good job Polar! Don’t let that bad cub nurse from you!
|Polar's baby (left) with Diggory's baby (right)|