Monday, February 28, 2011

Hierarchy, interrupted?

RBC is the current (?) alpha female of North clan. She's a tough girl alright, when she has to be, but her personality leaves much to be desired. I can't tell you how many times I've been at a den, struggled to keep up with all the hustle and bustle that usually accompanies den sessions with lots of cubs, but had this one, oddball hyena sacked out (usually deep in tall grass and covered in mud) that didn't move an inch the entire time. Take a quick look at her ear and, sure enough, it's RBC. She's the hyena that doesn't even put her head up when 5 other females lope away from the den, whooping like crazy. Her cub will be 'wrongfully' aggressed on by other, lower-ranking cubs and she just chills out. For some unknown reason, she just can't be bothered.

DIGS is the current (?) #7 female of North clan. During my short 7-month tenure, she's been somewhat of a transient hyena. We would see her often-ish at the communal den, usually sacked out and nursing her cub (who is now a subadult), SANA. She never seemed to be in the center of activity, but she was never the loner at her own exclusive den, either. It wasn't shocking to see her at the dens with everyone else, but it also wasn't shocking when she would go missing for a week or more.

Both of these ladies made a contribution to the baby boom of late. TYPH (Typhoon, RBC's cub) is almost 4 months old and seems to be doing well. MARI (Mariana, DIGS' cub) is almost 2 months old and also seems to be growing steadily.

Just a couple of weeks ago I witnessed - what I believe to be - a pretty extraordinary event. I showed up at one of the communal dens to find RBC bleeding from fresh puncture wounds on the left side of her belly. She also had a little blood coming out of her mouth. She seemed to be just fine walking around, but I could tell it was uncomfortable for her to sack out.

I was surprised to see her up and moving around, which was when she started doing some weird stuff. After some low-grade aggressions on some lower-ranking hyenas (normal), RBC went bristle-tailed (showing excitement), wandered around, groaned, and pawed the ground. A lot. Ground-pawing is something that is most commonly done by males when courting females. Hyenas also paw the ground after urinating or defecating. There's speculation that it may also play a role in scent marking (this alternative purpose of ground-pawing is something I read in an outdated book on hyenas that suggested there could be interdigital glands that release a substance used for marking. I don't know if there have been recent studies on the phenomenon). Males do it randomly when no females are around, so I'm inclined to believe that there are motivations other than courtship. Before this day, the only other time I had seen a female paw the ground was after urinating or defecating.

Soon after this DIGS arrived at the den. In response to DIGS' presence, RBC immediately giggled and went into a submissive posture (and was still bristle-tailed). Um, WHAT? I had to take a few extra minutes to confirm that I had the IDs correct. Yup, I definitely saw what I saw. Rumor has it that not even Kay has heard an alpha female giggle. Later, it happens again. RBC was bristle-tailed, in submissive posture, and giggling, while DIGS was bristle-tailed, groaning, and sniffing her.

I know what you're thinking. RBC is hurt. RBC wanted to prevent any potential conflicts or confrontations to avoid over-exertion while injured. Definitely, definitely possible, especially because it seemed like her submission wasn't elicited by any aggression on DIGS' part. However, that doesn't explain RBC's voluntary participation in aggressive interactions before and after her giggling bouts with DIGS (which happened with an intensity that seemed uncharacteristic of RBC, but pretty standard for most adult females).

Perhaps RBC and DIGS got caught up in some altercation and DIGS is actually the cause of RBC's puncture wound (I also noticed later in the session that DIGS had a wound on her right cheek, suggesting they were both involved in an antagonistic interaction, perhaps with each other, lions, and/or other hyenas). If DIGS did indeed hurt RBC, intentionally or otherwise, I can understand RBC's immediate submission.

Or, DIGS is working her way up in the world. Just this morning DIGS seemingly had it in for JONI, who currently sits in the #4-5 spot. DIGS' aggressions were clearly not cub-related (maternal interventions, which I alluded to in my previous post, are common and don't necessarily follow the strict hierarchy), and JONI appeased like she was standing at the door to heaven.

To be fair, we don't know as much about the rankings as we'd like to. I'm speaking for Serena camp, now; I suspect that Talek camp - the mzee of fisi camps - has a pretty good idea of who should be submissive to whom in their own clans. But after studying our hyenas for only 3 years, we are still trying to sort out the pecking order these guys have in place for themselves. So, really, a big switcheroo of (what we know to be) the rankings shouldn't be all that surprising to us, given how little we actually know.

Keeping that in mind, it's still fascinating. For the past 7+ months it seemed like our ladies had been behaving consistently with what we thought was their place in the hierarchy. But given that there have been only 2 instances of possible change in one month, it is all the more clear to me why still, after 3 years, we have not yet been able to fine-tune the rankings with the limited data that we do have.

Friday, February 18, 2011

Baby Boom

We live exciting lives, us hyena researchers. Chasing carnivores across the African savanna, witnessing the couple-second transition of an ungulate full of life to an ungulate as an early-morning snack, and getting regular, nighttime visitors in camp (namely hippos, buffalo, and elephants). However, in my opinion, there are few events more exciting than the first glance of a brand new hyena cub.

It all started at the end of September. We had finally re-discovered the active den sites of all three (Serena) clans, and the hyenas were more social than usual. It was an exciting time, especially for me as a new(ish) RA on the project; I finally felt comfortable with a majority of the spot pattern IDs and the daily behavioral data collection. I was learning behaviors, and the hyenas were giving it to me.

Then we started noticing that certain females were acting unusually protective of their dens, typically never going more than a meter or two away from the hole unless it was to chase away other hyenas. We started seeing low-ranking females act aggressively towards higher-ranking females. Unusual, considering the strictly-followed social hierarchy of spotted hyenas.

Finally, I saw my first little black cub. Only 4 weeks old: about a tenth the size of its mother with pure black, velvety fur, bare, stretchy skin under the arms, a thin, wormy-looking tail, and fearful eyes. Who would have thought that such gnarly, tough creatures could start off looking so cute and fragile? (though I think hyenas of ALL ages are cute)

The next day we discovered that this cub had a twin. We showed up at the den and the new mama was nursing not one, but TWO cubs. By the end of the week we discovered 4 more brand new cubs in this clan (Happy Zebra). By the end of the month our other two clans also decided to hop on the baby bandwagon. 3 cubs in North, 2 cubs in South.

I was excited. I got to name some cubs and come up with lineages for new moms. It was fun to watch the cubs grow up and gain their confidence (for the first couple months most cubs will shy away from a blade of grass that blows in the wind). Slowly the cubs went from being all-black to having a dusting of white fur on their faces and foreheads. Eventually, spots started to develop on their shoulders and forelegs. Almost, just barely, enough to start differentiating between the little black fur balls.

Then came the boom. November and December yielded 22 new black cubs. January, 11. Still exciting, but now stressful. 33 more individuals to name, age, sex, and keep track of at the dens. More often than not we would find a batch of unaccounted-for cubs at a den and not learn who the mothers were until days or weeks later (when we finally saw them nursing). As soon as the cubs got old enough I was scrambling to take photos of their one or two shoulder spots just to try and figure out who everybody was. Without nursing information, or having spots to go by, there was virtually no way to confirm the identities of these young cubs.

So I've been busy. I'm trying my best to manage the influx of new hyenas while still discovering more. Just this month I've seen 5 more new cubs, and I'm waiting on at least one more subadult-now-turned-adult female whom I saw with a torn phallus recently (MSTL, for those of you in the know).

We've even had two litters of triplets, a rarity in the hyena world (and the first, for the Serena side): CLOV, the alpha female in South clan, and SILK, a low-ranking female in Happy Zebra clan. We have already, unfortunately, confirmed the death of one of CLOV's cubs, MAYO. It survived to be about 2.5 months old. I have not seen SILK or her cubs in quite a while, so their fate is unknown as of yet.

Otherwise, cub mortality seems to be low. I am only certain of one other disappearance, but I suspect there are 3 more. With the clans' best interests in mind, I hope these cubs live. We are starting to see some of the subadult males less and less, which means they're probably dispersing. I find it hard to believe that our already-small clans are at carrying capacity, so we could use the boost in numbers. With my own self-interests in mind, I REALLY hope these cubs live. I would (will) be devastated to see some of these cubs go, especially after having watched them grow up as if they're my own. They're already showing unique personalities. And they're just cute. See below.

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