Friday, January 30, 2015

Fig Tree Flashback



Seeing Ashlei’s recent blog post, with the photo of Potter and Kibera brought on a powerful Fig Tree flashback…

Let me set the stage:

February 2014: We’d had 12 weeks of observing the Fig Tree communal den scene as they moved from Pallet Town Den, to Passion Fanta Den, to Tempest Den, and finally settling in at Nancy Drew Den. Much like the den Ashlei described for Fig Tree, all these dens were in the middle of an open plain. We would arrive early evening, park the car, and watch the comings, the goings, the interactions, and the cubs’ social behavior (read: unbelievable cuteness) for hours.
Nancy Drew Den, January 2014 (All photos from H. Couraud)
Jean Grey, perched on her mom Potter, with Wolverine nursing 
Thus was our pattern, one we looked forward to greatly each time we went out. Fig Tree has historically posed a challenge for researchers – the territory is farther from our camp and the conditions of the roads during rainy seasons make it very difficult to get to the clan regularly. We had a firm handle on who each of the cubs were, and were gathering very specific behavior data.

And then came February 23rd.
The excerpt from our notes read...

1758   @Nancy Drew D
            No hyenas visible

So began the search. A lot of stunning grasses…and not a lot of hyenas.

Though we were sad they were no longer at such a great den for viewing, moving communal dens is a normal part of hyena biology. Boydston et al found that the hyenas in the Talek clan move communal dens about once a month on average, though the length of time at any one den and the timing of the moves was highly variable (2006). Reasons for moving could range from human disturbance, lion presence, or parasite buildup at the site; it is a facet of hyena biology still poorly understood (Boydston et al, 2006). Higher-ranking females appear to lead more of the den moves (Holekamp et al., 2000) and the lower-ranking females then move as well – this keeps their cubs with their peers and able to benefit from the socialization and association with higher-rankers and their cubs (Holekamp et al., 1997). But I digress…

So, when you can’t find the communal den, a carcass session, or even lone hyenas, what do you do? We started with the GPS collars. 

February 26th we travelled to where Rohan’s (an adult female with cubs) points had been congregating. Why was she so far away? Had the clan moved a significant distance, or was this travel just a trip for ROH? Thanks to the individual personality of each hyena, it was impossible to tell. We didn’t find ROH, but we did see Wanugu! Our excitement at seeing one of the clan couldn’t extend much further however – seeing a male of dispersing age doesn’t necessarily give you many hints of where the rest of the clan is.

Then we decided to ‘den hop’. Twenty-two known communal dens later, we hadn’t found any new signs of occupation. Curiously, we did see three female sub-adults. Did that mean the clan was still in the area?

Then we took the follow-an-individual route, hoping to be led to the den. Fifty-five minutes of following later, night set in and we could not longer maintain a visual in the thicket on the hyena we were staying with.

By April 17th, we hadn’t had any luck, even after driving systematic transects across the plains. On our way home, we saw three large forms in the distance….hardly daring to hope, we drove up and confirmed we were seeing three adult female hyenas! The flicker of hope that ignited was quickly extinguished however when we identified them as females from the neighboring clan. That confirmed our growing suspicion – if adult females from another clan were meandering lackadaisically, the Fig Tree clan has certainly moved to another region entirely. 

Brazil, a Mara River clan hyena, on April 17th
April 23rd – Dave and I set out, heading into the northern region of the Mara where we had been searching recently. We were cautiously excited when we saw Donatello, one of the clan’s sub-adult females. A great sign, but one we had been fooled with before. Then we saw Wanugu – another good sign, but let me remind you of the dispersing male characteristic. And then I heard a slight, ‘Beep. Beep. Beep’. Our tracking was picking up one of our collared females! Now that was a good sign. We switched the headphones so Dave could drive and track, gradually picking up a stronger and stronger signal.

And then, at 1757….(hint: no impending dashed hopes here…) we found not just Fig Tree hyenas but 16 of them, cubs included! Our excitement was palpable and my joy was hard to contain to the professional research mode. (For the record, I did manage it, though with great effort)

If that wasn’t enough, nine of the hyenas began loping very purposely to the east. 
Red Rover, loping to the East
We drove off in pursuit, crested a hill, were afforded a stunning view of the landscape laid in front of us in the softening colors of dusk, and then rested our eyes on the two adult male lions, surrounded by 23 of the Fig Tree hyenas.




We hadn’t just found the clan, we had found their communal den, were witnessing a lion-hyena interaction, and had more Fig Tree hyenas in one place than I had seen in my entire time in the Mara to date.

After two months to the day of searching for and wanting to observe behaviors (read: ‘missing them’, in less scientific terms), this was a night I still beam at when remembering.

Sources

Boydston, E.E., Kapheim, K.M. & Holekamp, K.E. (2006) Patterns of den occupation by the spotted hyena (Crocuta crocuta). Afr. J. Ecol. 44, 77-86.
Holekamp, K.E., Cooper, S.M., Katona, C.I., Berry, N.A., Frank, L.G. & Smale, L. (1997) Patterns of association among female spotted hyenas (Crocuta crocuta). J. Mammal. 78, 55–64.
Holekamp, K.E., Boydston, E.E. & Smale, L. (2000) p. 587–627 Group travel in social carnivores. In: On the Move: How and Why Animals Travel in Groups (Eds S. Boinski and P. A. Garber). University of Chicago Press, Chicago, Illinois.


Wednesday, January 28, 2015

What Makes The Best Den

We have a variety of dens in both Talek West and Fig Tree. These dens can be found in areas crowded with trees and shrubs or open plains surrounded by ponds and luggas (areas surrounded by small bushes that fill with water when it rains). Each den comes with its own pros and cons and some are considered to be better than others. Below you will find a list of dens being used by the hyenas we study.

Theory of Mind Den

Theory of Mind Den is one of our newest dens. It is located in Fig Tree. This den is located on an open plain near a lugga.


 POTTER sacked out by the den with cub Kibera.

Pros: You can see everything (well everything besides what goes on inside the den hole). The 360 degree view that this den offers makes transcriptions (the notes we collect during observations sessions) much easier. There are no trees or bushes blocking the interactions between the hyenas or the spots of the hyenas. Without seeing the spots it can be difficult to accurately identify someone.

Cons: This den leaves the hyenas very vulnerable to threats. Recently we had a lion hyena interaction. During this interaction a couple of male lions approached the den hole and tried to stick their heads down the den. Fortunately none of the cute cubs or older hyenas were injured!

Den One Creek Den

This den is home to what we call the Royal Family in Talek West. Our matriarch along with her daughters and sisters call this den home. Many other high and mid ranking hyenas can also be seen in play with the cubs here. Den One Creek, or DOC den as we here in Fisi camp like to call it is located near a lugga and surrounded by a thicket. There are also lots of trees and bushes on each end of the den hole.


Wrangler sacked out by the den being pestered by her two cubs, DEGE and ENOU.

Pros: The den offers both protection and shade. It would be very difficult for a large animal such as a lion or buffalo to get through the thicket and near the den hole. This den is also filled with playful and rambunctious cubs that like to explore and come very close to the car.

Cons: Many of the hyenas interact within the thicket. This makes it difficult to not only ID them but to also determine what kind of interactions (aggressions, greetings, nursing, grooming) they are doing. Good luck recording all of the behaviors that happen at this den. Once the hyenas move into the thicket every observation session becomes a challenge.


Kind See ‘Em Den

Well the name of this den says it all. Kind of See ‘Em Den is located in Talek West and is surrounded by a host of trees and bushes. It is home to most of our low rankers.


One of out mystery cubs getting ready to emerge the bushes. 

Pros: The den offers protection from threats such as lions, buffalos, and elephants. There are no roads that lead to this den, which means less traffic. This den is the perfect formula for a serene and quiet den session.

Cons: You cannot see anything! The den holes are located deep within the thicket. It’s a lucky day when one of the cubs or moms decides to emerge the den to give you a glimpse of their spots. Many of the adult females who live near this den have had cubs that we still have not seen. We suspect that these mothers have cubs due to their torn phalluses (indicates when a mother has given birth). These mothers and new cubs have left us with a lot of work to do. It is going to be difficult to determine which cub belongs to which mother. Many of the moms nurse within the thicket leaving us with little clues as to whom these cubs belong to.


What do you think of these dens? Which one is your favorite? Leave your comments below.

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. 

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