Wednesday, January 25, 2017

To familiarize or not?

Hello everyone, it's me again, that grad student testing hyena cognition. It's pretty standard protocol in the cognition testing business to familiarize your subjects with the testing apparatus so that fear doesn't stop them from participating. I've always thought that seemed like sound science and I've been doing this with the hyenas. Wild hyenas tend to be more fearful than captive hyenas and I want every hyena to have a chance to solve the box, not just the bold ones.

For those of you new to our blog, my "testing apparatus" is a multi-access puzzle box. It's a box that's baited with food on the inside that has four different "doors" or ways of opening the box to get the food inside. During a familiarization trial with the hyenas, I take the lid off of the multi-access box and put it on its side so that hyenas can just walk up and eat the food from inside the box. This way they get used to the smell and texture of the box and learn to associate it with food (and not scary things).
Hyenas investigating the box during a familiarization trial. 
However, I've noticed that a large proportion of hyenas who have opened the box did so on their very first time interacting with it. Yep, zero familiarization trials. This has happened enough times that I've started to wonder if giving the hyenas familiarization trials might also make them lazy. I.e. they've learned the box has free food inside it. When they're given a test trial they don't try to open it because they're used to getting the food for free. I've had many hyenas sniff around the box once and then sack out just a few meters away, to all appearances just waiting for the box to magically open.

Hyenas investigating the box during a test trial. Many of these hyenas had familiarization trials, but TERV (no familiarization trials) ended up solving it. 

Then I had this trial yesterday with Burger (BRGR). I put out the box for ADON, whose had 2 familiarization trials but ADON wasn't interested and remained sacked out in her spot under a shady bush. After I put out the box BRGR emerged from the bushes. BRGR has watched other hyenas' trials with the box but she'd never contacted it herself before nor had a familiarization trial where she fed from the box. Yesterday, however, she was quite curious about it; after less than a minute she opened it using the door knob. My excitement slowly turned to dismay as BRGR never got up the courage to eat the food from inside the box after the initial shock of the door knob opening. Most hyenas who open the box once are fairly good at opening it again. But since BRGR didn't feed, she won't be able to form an association between solving the box and getting food. I have no idea what her reaction to the box will be next time she sees it! Now I've learned though what the benefit of a familiarization trial can be! If BRGR had stuck her head inside the box to eat during a familiarization trial I'm sure she wouldn't have been afraid to stick her head inside this time. I've decided that I should still attempt to give all hyenas at least 1 familiarization trial which will hopefully balance the cost of potentially teaching the hyenas to be lazy with the benefit of teaching them not to be afraid.

Thursday, January 19, 2017

All in a Day's Work

So I had a pretty great day the other day – this day being January 17th 2017.  The den sessions on morning obs were pretty normal, took place in South territory.  There is a running joke in Serena about obs in South.  We call them Sobs (South Observations), due to the number of hyenas normally present at den sessions and the difficulty of gathering all the CIs and IDs at the session.  Normally, you really start sobbing if you are doing solo Sobs, as it makes it that much more difficult to keep track of everyone.  However, this morning I didn’t sob, not even a single tear.  On top of that, we added a new mother to the ranks of moms in South: Blue Band.  She was nursing her two cubs this morning in a quiet corner of the communal den.  By this time, it was getting light out so I snapped a couple of photos of the kids to age them later and went on my merry way to explore the territory.  This is when things started to get really crazy.  While performing a prey transect, I ran into three subadult female lions and a subadult male – playing kill the carrier with a black-bellied bustard.  Turns out a juvenile martial eagle had killed the bustard, but this jubilant pride of lions decided they wanted the kill for themselves – the martial had no choice but to concede, as he watched glaringly from a decently-sized termite mound a couple of meters away.  With my prey transect unfinished, I reluctantly left the lions and forged ahead, deftly shooting (with a rangefinder, of course!) zebra and topi left and right.  I didn’t get more than 300m farther down the transect, when I chanced upon three cheetah brothers drinking from a small spring at the top of a lugga.  These guys are one of the few resident cheetah coalitions in the Mara triangle, a rare sight indeed.  The Mara allowed me complete my prey transect without any other ludicrous events occurring.  At this time, I looked down at my watch and realized I was going to be about half an hour late for breakfast.  So, with my stomach alarm rumbling, I sped back to camp. 

One of the three Lemai brothers, who are residents now in the Mara.  It is thought that they emigrated from Serengeti.
Throughout the day, I completed the mundane daily tasks of Fisi Camp, such as transcribing data, car checks, and cleaning the solar panels that power camp, quietly contemplating how spectacular this day had been so far.  Fortunately for me, the Mara still had some big surprises in store for me.  I left to head to North territory that evening and upon approaching the den, I noticed four conspicuously large boulders within 200m of the den that had not been there two days ago.  It took me about half a second to realize they were, in fact, biotic and slowly moving between the shrubbery.  Cape buffalo were quickly ruled out due to the coloring and lack of fur.  As soon as one of these creatures lifted their head, the search image instantly materialized in my cerebrum: black rhinoceros.  I almost popped straight through the roof of the land cruiser, as I haven’t seen a rhino in two months, much less four at once.  These four rhinos represent approximately 15% of the population in the entire Mara triangle so it was certainly a special sighting.  Especially considering the fact that I had them all to myself, no tour cars in sight.  Although, I would’ve loved to stay with this incredibly endangered species all night…I had a job a job to do.  At this point, I was only 100m away from the den and could still see the rhinos quite clearly anyway.  North den is pretty quiet at the moment, as the old cubs are just about to graduate and the young cubs only emerge from the den when their mothers are around.  Luckily for me, Waffles, the matriarch of North clan, who we’ve expected to have been harboring youngsters in one of the den holes, arrived from the East. Given how this day has been going so far, I believe you can foretell that I did wind up seeing Waffles’ cubs nurse from her for the first time.  So absorbed was I in acquiring photos to age the cubs with that I didn’t notice the lumbering fortress of elephants, forty strong, taking a beeline to the den and showing no signs of stopping.  As you can imagine, this was quite an intimidating sight and I decided that I should flee the scene before they got too close.  I could’ve just given a wide berth to these determined pachyderms, but I wanted to see how the hyenas would react to the approaching behemoths. 

Rhino Squad......Assseeemmmmmmbllleeeeeeeee!
The rhino mini-herd was less than 100m from the den now and on the opposite side as the elephants.  Given the number of calves in this herd, I figured that even if the elephants were oblivious to the impending hyena den in their path, they would not be willing to approach the rhinos and risk altercation.  Taking care not to not disturb the peacefully grazing creatures, I slowly placed them between myself and incoming elephant herd.  The rhinos didn’t mind one bit and, with the car off, seemed to accept me as a wonky member (a land cruiser with an H-antenna sort of looks like a rhinoceros) of their family group by moving closer.  Through my binoculars, I could see Waffles at the den.  At about 10m, the elephants realized they were walking through a large carnivore den, and responded accordingly – an orchestra of trumpets, an extravaganza of head waves, and a spree of mock charges.  Unbelievably, in spite of all of this hullabaloo, Waffles didn’t even blink once.  She stayed sacked out where she was nursing her cubs, not five minutes before (the cubs squealed and ran into the den as soon as they caught a whiff of the forthcoming danger), and lazily napped through the whole ordeal.  Although I can’t determine whether it was bravery or stupidity, I can definitely ascertain that this matriarch has some serious panache. 

Waffles and the Pachyderms (A great band name should anybody be in need of one).  This was only the first wave!

After about 45 minutes of being stonewalled by Waffles, the elephants abandoned their turtle shell formation with their calves in the rear and nervously peered over their shoulders every couple of paces to make sure Waffles was not in pursuit.  My benevolent rhino shield worked wonderfully as well – the elephants veered off to the escarpment as soon as they made it to the other side of the den.  With a magnificent sunset at my back, I left my companions, grateful for their assistance, and returned to the den to continue recording behaviors.  Well, it’s all in a day’s work out here in the Mara.

Bonus Shot: A rare January storm rolls in from Tanzania as I leave the den, while the Mara Conservancy performs a controlled burn along the escarpment.  Obligatory Lion King Reference, the atmosphere has an eerie resemblance to the penultimate scene of the movie.

Tuesday, January 17, 2017

Can you feel the love tonight?

Last week, I stumbled across something unforgettable:

A pair of lions alternates between resting, mating, and fighting!

This amazing wildlife sighting got me thinking: What makes one male more attractive than another? Why does the female invite the male over and then fight him off? What are the chances that she will have cubs?

What's in a mane?

Rather than a crown, the King of the Jungle sports a thick and beautiful mane -- perhaps his best claim to fame. However, not all manes are created equal. Lions' manes vary in length and coloration, conveying important information to competing kings as well as flirty females.

Male lions' manes grow longer and thicker as they approach adulthood. This young subadult is approximately one year old (lions in all photos were aged using the Mara Predator Project's guide to aging lions). Males at this age begin to develop a small, pale "mohawk mane."

These young brothers sport the very beginnings of what will one day be thick, charming manes.

This young adult has a medium-sized, blonde mane. He is in his prime and reigns over his own pride. His face already bears battle scars. As he ages, his mane will continue to grow longer and darker.

This male lives north of our camp and is known as "Scar." Scar is very old and relies on the females in his pride to take care of him. He is missing one eye, is extremely gaunt, and limps badly when he walks. His distinguished mane has grown thick and dark throughout his long lifetime.
Lions' manes have perplexed scientists for hundreds of years. One hypothesized function was communication, but what specifically could this communicate? To find out, researchers at the University of Minnesota's Lion Center asked the lions.

Anna Club Plush Toys of Holland donated two life-sized toy lions to the Lion Center: one with a dark mane and one with a light mane. (Photo obtained from the the Lion Center's Mane Research web page.)
Two toy lions were placed near lion prides: one toy lion had a long, dark mane and one had a short, blonde mane. Reactions of males and females elucidated the role of manes in communication among lions.

Male lions were quick to approach the toy lion with the short, blonde mane. This suggests that long, dark manes make male lions look formidable to competing males. Why would this be so?
      •Researchers at the Lion Center found that males with short manes are often those that have 
      recently suffered from injury or illness, thus potentially reducing their current fighting ability.
      •These researchers found that males with dark manes had higher testosterone levels than males 
      with pale manes, suggesting that they are more aggressive.
      •Males with dark manes were also found to recover from injuries more effectively than their pale-
      maned competitors, as well as sire a higher proportion of surviving cubs. Thus, dark manes likely 
      indicate higher potential reproductive success.

Dark manes don't only say, "back off" to male competitors; they also say, "come hither" to females. In this experiment, female lions paid no mind to mane length, but couldn't resist a dark mane!

Female lions are suckers for dark manes. Selecting a mate with a dark mane may mean that she will have more cubs survive. Besides, who wouldn't want a son with that handsome, dark mane? (Also known as the Sexy Son Hypothesis.)
So, long, dark manes are better than short, pale manes. Mystery solved. Right?

Wait... then why don't all males have these long, dark, and handsome manes?

Females aren't the only ones who find manes hot. They're hot for the males who sport them too! Manes make lions hot, and the dark manes are even hotter -- both literally and figuratively speaking. Dark manes may lead to over-heating in males, which leads to elevated proportions of defective sperm. Over-heating males also have to eat smaller meals, meaning that they have to eat many small meals. This necessitates more foraging time.

One of the stars of our story sports a particularly handsome mane!
One morning while searching for our hyena friends, a particularly handsome male caught my eye. I quickly realized that I wasn't the only one whose attention he had caught. A flirty female had decided that he was a worthy suitor... This is where the story gets good!


A Public Affair

After noticing this male meandering through the tall grass, I quickly noticed a female rolling on her back and reaching out to him playfully. I've seen enough nature documentaries to know what that means!

These female is in estrus and has selected this gentleman as her mate.
The pair spent hours together. They lied close together in the grass, with their paws touching. Each time she stood up -- or even lifted her head -- he jumped to his feet and pursued her. She assumed the lordosis position and he mounted her. As they mated, she emitted a continuous grumbling sound as he roared into the back of her neck. (Males often bite the female's neck during copulation, likely to elicit passive behavior from their females partners temporarily.)

The male roars as he copulates with this receptive female.
Male cats have barbed phalluses, which rake the female's vaginal walls. This is believed to induce ovulation, thus allowing her to become pregnant with his cubs. However, this can be painful! Each mating bout ended in a small spat. However, they both seemed to put it behind them within mere seconds.

Each mating bout ended in a small lovers' quarrel.

The pair mated many times over the course of an hour. Lions remain together for the female's entire estrus period (four days!), mating  multiple times per hour.


Just the beginning

If this pair was successful, she will give birth to 1-6 cubs in approximately 3.5 months. She will cooperate with the other females in her pride to raise them. Females even nurse each other's offspring!

A lion family makes themselves at home right outside of our camp!

Becoming pregnant and giving birth is only half of the battle. Cub survivorship is very low in lions. It has been estimated that for every 3,000 copulations, only one cub will survive to one year of age.
Moments after leaving the mating pair, I stumbled across a lioness leading her fat, healthy cubs across the savanna.

Lion populations have declined by more than 40% over the last two decades alone and they are now considered a Vulnerable species (IUCN Red List). If this female bears cubs, they will help to reinforce the lion population within the Mara Triangle. As a result of strict and thoughtful management, the Mara Triangle offers excellent habitat to lions and other carnivores. This female will have a beautiful place to raise her cubs!

To learn more about lions in the Masai Mara National Reserve, follow the Mara Lion Project and the Mara Predator Project!


Tuesday, January 10, 2017

Hyena Cognition - Hall of Shame

Opening the multi-access box is proving to be a challenging task for wild hyenas. The MAB tests a hyena’s ability to innovate, i.e. learn something new. So far only a few hyenas have shown that they have what it takes. In November, I blogged about hyenas who are champion box openers. This time, I’ll share a little about hyenas who have made contact with the box on multiple occasions, but still have yet to open it.

Bindi – BIND

BIND is the #1 moocher. She’s a high ranking subadult female (her aunt is PBUT, the alpha) and she’s had MANY chances to open the box. However, she’s learned that if she sits and waits, someone else will open the box and then she can use her high rank to push the other hyenas out of the way (including the unfortunate soul who opened the box) and eat all the food inside. In the video MUSS opens the sliding door, runs off with his meat, and BIND promptly comes up and monopolizes the box in her typical fashion.

Clarity – CLTY

Clarity is a subadult male of unknown parentage, which also means unknown rank. Sometimes he hangs out with high rankers but often acts submissive and nervous. CLTY has had many familiarization trials and made contact with the box every time he’s been presented with it suggesting that he’s not afraid of it. However, as well as being socially timid he’s also timid in his interactions with the box and despite contacting the box he’s never tried to bite or paw at it, two behaviors that are necessary to open the box.

Hail – HAIL

HAIL is MVUA’s twin sibling, who is a champ at opening the box. He’s the dominant cub in the litter but he usually seems content to simply let his mother PBUT and his twin sister interact with the box. Anecdotally, it seems like dominant cubs tend to be less bold and explorative than their subordinate siblings. Perhaps the subordinate cubs are just more willing to take risks in order to obtain food! Are you just lazy from growing up as the dominant cub, HAIL?

Princess Buttercup – PBUT

PBUT was going to the be the star of the hall of shame. She was one of the very first hyenas to complete familiarization trials and the first hyena ever to receive a test trial. However, after sniffing the box for thirty minutes she gave up and walked away. I gave her trial after trial after trial including some where other hyenas started to open the box while she was sniffing it. Being alpha, when other hyenas opened the box she also got to feed. Maybe she learned something socially, because after many failures PBUT is now a champion box solver! 

PBUT is now the first hyena to have learned 3 out of 4 solutions. After opening it once, PBUT became a really persistent box solver and is flying through her trials. She opened the push flap first (usually the hardest for hyenas) by pawing it and nudging it inwards with her nose. 

After mastering the push flap in consecutive trials, she used her paws to pull open the drawer in several consecutive trials. Now she’s opened the door knob twice, this was the hardest one for her because she had to learn to use her mouth to bite and pull it open since it doesn’t easily open by pawing it.


You’ll notice BIND in the video asleep to the left, standing up the moment PBUT opens it to come in and get a bite!

Princess Tiana – TIAN

TIAN is, you guessed it, PBUT’s twin sister. She was the subordinate cub in the princess duo and like her daughter BIND, TIAN is a big moocher. Probably because PBUT and PBUT’s daughter MVUA are now masters of the box TIAN has learned that she can simply sit and wait for someone else to open the box. It’s interesting that just being high or low ranking does not predict who opens the box! However, her behavior is fairly similar to PBUT’s before PBUT realized that pawing and biting would open it, so you never know… TIAN could surprise me and figure out how to open it someday.

TIAN looks a lot like her sister PBUT, but she has much paler spots.

Trouble – TRUB

TRUB is a high ranking subadult hyena who has had fifteen trials total with the box including familiarization trials and still failed to open it. She’s mostly a “stand and watch” hyena, but she often comes up and sniffs around the box briefly before backing away to watch the other hyenas. Her mother is ADON so she’s not low ranking, but like CLTY she’s timid in her interactions with the box. She’s not a moocher like BIND, but she maintains some curiosity about the box so who knows how her future trials will go!

There are a lot more hyenas who have made contact with the box and even bitten or pawed at it yet still failed to open it even once. However, for a lot of these hyenas they’ve only had one chance at the box and many times there are higher ranking hyenas present that inhibit their ability to explore the box. I’m hopeful that with enough trials most hyenas will become proud members of the hall of fame!

Michigan State University | College of Natural Science