Monday, January 26, 2015

SOUNDS OF KENYA: Lions and vervets and calls, OH MY!

One of our concerns in using our stuffed lions on hyenas, is whether they will “take the bait.”  Are the stuffed lions real enough to fool them into behaving as they would in response to a real lion?  The jury is still out on the hyenas being fooled, but a couple of weeks ago, we inadvertently tested out another species:  The vervet monkey.

This is as majestic as vervets are capable looking.


In the process of unloading the lions from the back of the truck and putting them away in their tent (yes, the lions have their own tent), a single male vervet got a good look and immediately started alarm calling.  Keep in mind, we were carrying the lions at this time.  One would think that might clue the vervet in, but he continued to alarm call until we got both lions safely locked away into their tent with all of the windows closed.  Luckily, this gave me a great opportunity to get in close and get a good recording:

Friday, January 23, 2015

Poor Little Guy: ACIN's necropsy

Anyone who has read this blog has probably seen that after spending so much time with these animals, we researchers can’t help but get quite attached to them. We get to know every hyena as an individual, which makes it very hard when we lose them. I have been at Fisi camp long enough to have seen many animals go missing, and several cubs die (and be eaten by other hyenas) at the dens, but last month I did my first necropsy.

So first, an introduction to ACIN:

ACIN was one of the first hyenas I learned to identify at Happy Zebra den. When I arrived in the Mara he was six months old and had beautiful spots.

ACIN, showing off his spots
ACIN was very outgoing and bold; he wandered farther than other cubs and was always approaching and exploring the car. He was also a little troublemaker, and was one of the stars of Emily's blog post, The Car is not Food.


Emily, who named him, sent me this after she heard that he had died:

ACIN, was a wonderful and naughty cub that will be dearly missed.


He was named after a family of toxic proteins called astacin metalleoproteases. They are proteins found in many types of animals but were characterized in the spider venom I was researching in undergrad. We were able to characterize the toxic proteins in many species of haplogyne spiders, woo hoo! Astacins act by eating away at tissue (yuck) so the spider's venom can travel more effectively through the tissue. We injected crickets with different concentrations of venom to determine how nasty the venom actually was and how lethal. At the high concentrations it basically turned the crickets insides into soup. Lovely, I know. 

Super naughty but super adorable, that is how I will always remember that little guy.” 

He was a particular favorite of Sarah's, whose research involved feeding cubs milk powder to try to get them to fight, because he was always the first cub to find the milk powder.

ACIN's mom, SILK, was the lowest ranking female in Happy Zebra, which made him one of the lowest ranking natal animals in the clan, higher only than his older brother, Furadan. He was raised in a communal den where PIKE (the matriarch of Happy Zebra), along with EREM, ARBA, and COEL, all high ranking members of the royal family, were also raising their cubs. This gave ACIN a little bit of a rough start to life; his mom was often chased away from the den by the higher ranking females.

Since that blog from Emily, ACIN had graduated from the den and we saw him several times exploring by himself, looking quite healthy and happy. It had been about a month since I had seen him, and several months since I had seen SILK, when I found him looking very sick on the night of December 18th.

I was the only researcher in camp, out on obs by myself, when I found him sacked out (lying down) near a watering hole. I noticed right away that he wasn’t acting normally; he looked extremely skinny, and he didn’t react at all when I drove up to him. I hung out with him for about 20 minutes and during the whole time he didn’t do much more than lift his head. When I came back to check on him the following morning, he had moved about 150m, but was acting even more lethargic, barely able to pick up his head.

ACIN on the morning of December 19th, about 15 hours before he died



That afternoon, Kenna and Eli arrived in Serena camp and we went back to check on ACIN. It had rained that day, and his fur was wet and matted, making it clear that he was even skinnier than I had first thought. He had moved about 100m, away from a track that a lot of tour vehicles use, but by that point he could not open his eyes and was moving his head feverishly. We came back around 8pm and he had stopped moving entirely, though he was still breathing. The next morning he was dead. We estimated the time of death to be about 10pm on the night of the 19th.

ACIN on the evening of December 19th, about 5 hours before he died.

On the morning of December 20th, about 8 hours after he died


ACIN died 3 days before his first birthday. Hyena cubs are typically weaned between 12 to 18 months, which means ACIN was probably still relying very heavily on his mother for milk. While it is not unusual to go a couple of weeks without seeing a low ranking animal, the fact that we hadn't seen SILK in several months, combined with ACIN's body condition, makes us think that the most likely explanation for his death is that SILK was killed, and ACIN slowly starved to death.

Cub starvation after the death of a mother causes 18% of all hyena deaths. Humans cause the same amount of deaths (18%), exceeded only by lions, who cause 27% of all hyena deaths (Watts & Holekamp, 2009).

Spotted hyenas have an average life span of 12 years, but the first two years of life are by far the most dangerous. In a study conducted in Talek, 48% of hyenas died before they reached one year of age, and 63% of all hyenas died before they turned two (Watts & Holekamp, 2009). Changes in life stages are particularly dangerous. Many cubs are killed by other hyenas right after they are moved from their natal den to a communal den, at about a month old (White, 2005). There is also high mortality when the cub starts to graduate from the den, and right after they are weaned and begin to visit kills (Watts et al. 2009).

On top of those not great odds, ACIN was low ranking, which made him even more likely than other cubs to die before reaching sexual maturity (Watts et al. 2009).

Despite knowing that the odds aren't great for each of these little guys, it was still somehow surprising to find him dead. After photographing ACIN's body, we brought him back to camp, and started the necropsy. The first step was to weigh him, and take body and teeth measurements.


video
A timelapse of Kenna, Eli, and me measuring ACIN

ACIN weighed 18.45 kg, while the average weight for cubs at 1 year old is 29 kg. He was more than 23 pounds underweight for his age.

You can see here how skinny he was

The skulls of hyenas at a) 7.5 months, b) 14.4 months, and c) 22.2 months old
(Watts et al. 2009)

ACIN's skull

You can see on his skull that ACIN's sagittal crest (the peak on the top of the skull), and his teeth were not fully developed, as is normal for a cub of that age. The steep sagittal crest of the hyena provides a large surface area for jaw muscles to attach, giving them their incredibly strong bite. However, this structure takes a long time to develop, and cubs are pretty bad competitors when it comes to carcasses, making them very reliant on their mothers. You can also see that all of ACIN's teeth are sharp, where on an older hyena they would be worn down from crunching bone. All of this makes it clear why ACIN would have had a tough time surviving on his own without a mom to nurse him or to get him access to carcasses.

After that we proceeded with the necropsy, which involved taking tissue samples from 16 different organs; everything from his heart and lungs to his gallbladder and pancreas. The final step was to remove and flense his head, so we could preserve the skull.

video
A timelapse of the dissection


ACIN's internal organs
Though I don't have a lot of experience looking at heyna guts, all of ACIN's internal organs seemed healthy and normal looking. His stomach, however, was completely full of hair that had formed several hard hairballs. It seems likely that he was feeding on undesirable carcass scraps before he died, but that they weren't enough to keep him alive.

The contents of ACIN's stomach
While the whole experience was incredibly emotionally draining, it actually was much easier doing the dissection than it had been to watch him slowly die over the course of a few days.


After finishing the necropsy, we took his body out the Breakfast Plains, which are right in front of camp, in our North hyena clan territory. Over the next couple of days we saw both Rocket Scientist and Hey Jude, sub-adults from North clan, visit ACIN’s decomposing carcass to roll in it, which pretty much completes the spotted hyena version of the circle of life.



Watts H.E. Holekamp K.E. 2009 Ecological determinants of survival and reproduction in the                    spotted hyena. Journal of Mammology, 90, 461-471.
Watts H.E Tanner J.B. Lundrigan B.L. Holekamp K.E. 2009 Post-weaning maternal effects and the                          evolution of female dominance in the spotted hyena. Proc R Soc B 276 (1665): 2291-2298
White P.A 2005 Maternal rank is not correlated with cub survival in the spotted hyena, Crocuta                     crocuta. Behav. Ecol. 16, 606–613. 

Wednesday, January 21, 2015

New RA - Serena Camp: It's Good to be Back!

Jambo! My name is Spencer Freeman; I'm the new research assistant in Serena camp. I flew into Nairobi ten days ago on the 10th of January, and have been in Serena since the 15th. Its hard to imagine a more beautiful view of the park! I'm currently a student at Kalamazoo college pursuing a bachelors degree in biology, but I'm taking a year off to work on the hyena project in the Mara. My goal as of now, after I finish my undergraduate degree, is to go to grad school for a PhD in a biology-related field, but I'm still trying to narrow it down. Hopefully this year will help!
This past Summer I was a BEAM student (behavioral ecology of African mammals) in Kenya. BEAM is a three week study abroad program run by Dr. Holekamp's graduate students. During my three weeks on BEAM I traveled to Meru, Nakuru and, of course, to the Mara. I learned all about the wildlife and ecology in Kenya, and got a great introduction to the kind of field research that is done out here. When the three weeks were up, I realized that I had fallen in love with the Mara, and knew that I'd have to come back.

Since I've been back in the Mara, I've been greeted by lots of familiar faces:




Seen some amazing views:



And, of course, started meeting some of the guys in the clans!




I couldn't be more excited to be back, and I can't wait to let you know what adventures the next year in the Mara brings!

Monday, January 19, 2015

New RA, Nairobi, Nakumatt

Greetings! I am Matt Farr, one of the new RAs (Research Assistant) in Fisi Camp.  I am a recent graduate, May 2014, of Purdue University in wildlife biology.  I decided prior to graduation to take a year off before I started graduate school, and I have been working wildlife technician jobs in various locations to simultaneously travel and gain field experience.  Since joining the transient/hobo life-style of a wildlife technician, I have worked on a variety of research project in a short amount of time.  I spent 6 months in the Sierra Nevada Mountains working with fisher (Pekania pennanti) and marten (Martes americana) for the US Forest Service.  I returned to Indiana to work for 2 months as a technician for Purdue University conducting fieldwork on hellbender (Cryptobranchus alleganiensis) and river otter (Lontra Canadensis) research. 





I have once again shouldered my bindle (or in my case a yellow duffle bag) and relocated to the Maasai Mara Reserve.  I arrived in Kenya on January 8th, but I have been in the Mara for less than a week.  The majority of my experience so far contains the trials and tribulations of Nairobi (where the rules of the road do not exist).  I spent my first week in Nairobi running errands with Ashlei, Chase, and Spencer, another new RA.  Each camp requires supplies from Nairobi that are not available in the Mara; therefore, a trip to Nairobi is necessary every 4 – 6 weeks.  We had to visit multiple shops to pick up the necessary items for camp.  We visited the gas filling station to refill our liquid nitrogen supply.  In addition, we stopped by a hardware store and a tent store for various supplies.  We also had to frequent our mechanic, Ian to fix the multitude  of problems with KAS, our Toyota Land Cruiser. 




But, the most critical resource in Nairobi to the success and functioning of the Fisi Camp is Nakumatt.  Nakumatt is a supermarket that is the Kenyan equivalent to Wal-Mart.  Walking into Nakumatt for the first time to do grocery shopping for camp, I was shocked by the selection of goods available.  Not only is the grocery shopping for both Talek and Serena camps done at Nakumatt, but additional supplies are also purchased.  We bought everything from a hacksaw to multiple jars of Nutella (a key fuel source for RAs).  We would roll up to the cash register with one or more carts stuffed and receive looks and questions as to why we needed 15 kg of rice or 40 packets of beef cubes.  We went to Nakumatt at least 10 times in the week I was in Nairobi, and it feels like I have spent more time so far inside the walls of Nakumatt than I have on hyena observations. 



Despite the good times at Nakumatt, I was more than ready to head to the Mara.  I was skeptical that all the supplies littered throughout the cottage would fit in KAS, but Ashlei and Chase assured me that all would be okay.  After stuffing KAS with supplies and a 6 + hour drive, we finally made it to the gates of the Mara.  We drove through the reserve to camp as I tried to keep my jaw from hitting the floor.  I have already seen zebras, giraffes, elephants, a hippo, wildebeest, gazelles, impalas, buffalo, cheetahs, lions, and hyenas.  I am quickly adjusting to camp life and beginning to learn the 120 + hyenas of Talek West.  I will let you know how it goes.




Friday, January 16, 2015

Because hyenas are great, and beautiful, and cute AND smart.

 
Let’s add a French touch to the hyena blog!!
I joined Kay’s lab last winter, for a two-year post-doc. My name is Agathe (in French, you would pronounce the A as you say it when the doctor is looking inside your mouth, and then pretend there is no H after the T, as it is usually silent in our beautiful language).
Ok, enough about French pronunciation. I’ve been in the Maasai Mara since last September, shame on me for not writing a blog post before, no excuse.

I’m an ethologist, meaning I’m studying behavior (of animals but also of human beings). My project here focuses on cognition, more specifically behavioral flexibility. Let me explain. 

   So, as you probably know, as primates, we are one of the species that can claim one of the biggest relative brain size among mammals. However, you would be surprised by what some birds can do, or even honeybees (Komischke et al, 2002). But, this depends on what kind of cognitive tests you are considering. In fact, cognition can be divided in two categories: physical and social cognition. While the first helps us deal with inanimate objects, we are able to understand our conspecifics intentional actions, perception and knowledge thanks to the latest (Herrmann et al, 2008). Of course, social cognition is most useful when living in a big society, which means frequent encounters with conspecifics. As a matter of fact, social complexity could be what drove individuals to have bigger and bigger brains by evolution (Byrne & Whitten, 1988). This is because living in a complex society enforced the need to understand its social rules, or to predict/understand the intentions of your conspecifics, especially if they’re higher ranking. As an example, when you are a middle ranking animal, you better be able to tell if that high ranking female approaching your kid is going to bite its head off, or just sniff it on her way and go. Or, before you come to rescue your BFF who’s being bullied, you want to make sure that his tormentor is not higher ranking, because he will remember you next time…

   You probably know by now how great our hyenas are, and like monkeys, they are able to recognize any member of their clan. Therefore they can remember their social status and choose to join someone in a brawl based on previous interactions and social affinity (Holekamp et al, 2007). Overall, they meet the criteria to fit in the social intelligence hypothesis.
   
   On the other hand, we know very little regarding their physical cognition (however, see previous work on our hyenas here), mostly because majority of that research focuses on primates. The social intelligence hypothesis predicts a high level of physical cognition along with social cognition. The key is to choose a task that can be done by several species, so that a wide comparison between species is possible. Let’s forget about IQ tests right away, only a chimpanzee would give the pen back when he’s done, and even a rather civilized baboon would eat it. Behavioral flexibility, the ability to adapt one’s behavior to solve a problem, is a good measure of general intelligence and can be adapted through various tasks.

   The hard part was to choose a task that hyena could solve without the use of hands, unlike their primate friends. Moreover, wild hyenas are very cautious toward man-made objects, hence I chose a task that they could do in several steps, to eliminate any bias of novelty on their ability to solve the task. So, to test their ability to display flexible behavior, I’m using a reversal learning test where the hyenas have to pull ropes to get access to meat, as a reward. They first have to learn to discriminate between two colors (black versus yellow), one associated with the reward, the other one associated with the absence of that reward. Once they have learned that, the rewarded and the non-rewarded colors are reversed and they have to suppress one behavior in favor of another to get the meat.

On this video: from the inside of the box: Decimeter, a subadult high-ranking female, comes and pulls the rope. It's her first time though, so she is kind of freaked out instead of taking the meat right away. 


video


  Conducting an experiment on wild hyenas takes time, especially when I have to find them across their wide territory and get them to interact with the device. After a very long habituation phase, I have now started the learning phase, trusting that my beloved subjects will learn it quickly (because I believe that they are indeed smart). Then, the best part begins: reversal learning!

Unlike Decimeter, KENG is used to the box and loves it. You can see  that she already got the meat on the right side. Here she is trying to pull the yellow rope, but the left tray is blocked : she now has to learn that only the black rope will get her meat! 

  Another time I’ll tell you how it went with lions (we could not find any hyenas that day, and I was curious…).

References
Byrne RW, Whiten A (1988): Machiavellian Intelligence..Oxford, Clarendon Press.
Jerison HJ (1973): Evolution of the Brain and Intelligence. London, Academic Press.
Hermann et al (2007): Humans have evolved specialized skills for social cognition: the cultural intelligence hypothesis. Science (317), 1360-1365.
Komischke et al (2002): Successive olfactory reversal earning in honeybees. Learning & Memory (9), 122–129
Holekamp et al (2007): Social intelligence in the spotted hyena (Crocuta crocuta). Phil. Trans. R. Soc. B (362), 523-538. 



Wednesday, January 14, 2015

Highs and Lows of the Talek River

In Talek camp, we live right next to the Talek river, which divides the park from the surrounding Masai lands.  For those of us who cross the river daily to run, play soccer, or visit friends, the height of the river is a constant question.  Normally, the river is low and easy to cross.  I do so by jumping on a stone in the middle of the river (blue path), although those with longer legs and more courage can just leap across like a gazelle (red paths).

How to cross the Talek River
When it rains, however, the river swells to precarious levels.  Overnight, the river can rise more than 2 meters and change from a tiny stream to a roaring rapid capable of moving logs and boulders.  (The stone I use to jump across the river was deposited during a rainstorm sometime in 2013.)  If we can hear the river rushing from the breakfast table, we all know that the river is no longer crossable.  Check out these comparisons between low and high river waters!



 

Given the changes above, flooding is a threat that worries all of us in Talek camp.  Stories of past floods have made their way into camp legend, as floods are rare but devastating enough to be recounted over and over again.  The most recent flood was in 2012, when it rained so much that the kitchen tent had to be evacuated (including the stove!) and taken down.  Luckily, the lab tent didn’t flood that time, so we didn’t lose any of our data or equipment.  In the 1990s, however, camp flooded so badly that we lost hundreds of dollars of equipment and months of samples, despite our best efforts to save everything we could.  This flood has been memorialized on a filing cabinet in Kay’s tent: the bottom drawer was totally flooded, but the middle drawer is labeled “stayed dry” and the top drawer is labeled “above the water line.”

Kay's filing cabinet, a relic from the 1990s flood
The person most worried about flooding is always Lesingo, one of our camp night watchmen.  His fear of water and the river is great, and I have complete faith that if the river ever were to flood, he would wake me up and say “Hatari!” ("Danger!") over and over again until I understood.  I only hope he never does.

Monday, January 12, 2015

The peculiarities of hyena hygiene


Hyena hygiene is pretty similar to what you would expect from any large carnivore. Hyenas get clean by licking themselves (or even better, by getting others to lick them), although, like domestic dogs, they jump all over the opportunity to roll in something gross they find on the ground.  So, while being clean isn’t always the highest priority for hyenas, it is not uncommon for us to find them cleaning themselves or others.

Despite its function, grooming behavior doesn’t always appear as hygienic to us humans as it does to the hyenas. Like seeing your pet dog thoroughly licking its anogenital region, observing hyenas during bath time is not always the most pleasant experience. CAMI, for example, decided to ruin our peaceful evening the other night be loudly grooming her phallus right outside of my car window. I have heard Kenna complain on multiple occasions that a cleanliness-obsessed cub cleaning its phallus ruined her attempts to record vocalizations from a neighboring adult.
CAMI gave came right up to the car to make sure we
could clearly see and hear her dedication to cleanliness. 
Despite their unsightliness, these behaviors are familiar to anyone who spends a considerable amount of time observing animals, and we don’t really bat an eye when we see them. We were, however, treated to a new variety of unusual grooming behavior the other night by EREM and ARBA, twins who currently each have pairs of cubs about the same age at the current Happy Zebra clan communal den. These two moms often arrive at the same time, and like good mothers, get right down to nursing and grooming their kids.
ARBA (left) and EREM (right), each dutifully
nursing and grooming one of their two cubs.
Wait, what exactly is EREM grooming?
While watching EREM and ARBA grooming their kids, we noticed them both take particular care to groom the anogenital region of their cubs. This didn’t seem particularly unusual to us, until we noticed that the cub would often distend its anal sac during this process. The cub’s mom would then thoroughly groom the anal sac, the area where the cub will eventually begin producing the scent marking substance called paste. Not only did we notice both EREM and ARBA doing this, but their cubs each took a turn so that both littermates got a thorough anal sac grooming from their moms.

Smaug distending his anal sac so EREM can
give it a thorough cleaning, while Puff anxiously awaits his turn. 

What is going on here? I don’t know, but I wonder whether this grooming behavior is purely hygienic or if grooming of the anal sac is an important part of the ontogeny of paste production. Paste is produced by microbiota that inhabit the hyena’s anal sac, so proper maintenance of the sac could be important to encourage the colonization of the bacteria that will eventually produce the individual’s scent. Alternatively, a cub’s mom may be directly inoculating her offspring’s anal sac with these bacteria from her mouth. While these explanations are purely speculative, there are others who know much more about paste production than I. If you are interested in learning about how hyenas host specific bacteria in their anal sac that produce their scent, check out research by Dr. Kevin R. Theis (https://kevinrtheis.wordpress.com/), who has discovered some very cool stuff about the complex symbiosis that underlies hyena olfactory communication.

Michigan State University | College of Natural Science