Roar

This past week has been a week of collaborations.

Last week I joined Ph.D. student, Meredith Palmer, in a day of field work. She works as a part of both Serengeti Lion Project and Snapshot Serengeti. Part of her work entails visiting the project’s camera traps and playing recorded lion roars with the intent of introducing the threat of predation to study the long-term predator responses of species in the area.

The modest appearance of the audio equipment cannot prepare you for just how loud this playback gets. When we stopped at the first camera, Meredith connected her iPhone to the speakers, and when the roar began, the speakers vibrated (along with my head), and I laughed in surprise. Is this how loud an actual lion would be if I were standing right beside it while it roared? Every note the lion sang echoed through my body.

I looked around to see if there were any animals reacting to the artificial predator, but there were none in sight. There were, however, topi and two ostriches at the next site.

When the roars began at this site, the topi that were just relaxing – some sound asleep – in the tall grass, stood up, vigilant. After a short time, they began to move off in a single file line – not without a couple glances in our direction. The pair of ostriches remained in the area, yet they also stood from their slumber, watching us intently, looking for the source of the roar.

These animals were not the only ones fooled by Meredith’s playback. At another camera site, just as we were finishing up, I looked out the window to find two tourist vehicles on the side of the road with people standing through the pop-top roofs, binoculars upright, searching for the roaring lion. Both Meredith and I laughed as we joined the main road again, watching the first of the two tourist cars drive away at the sight of us. “Sorry, there’s no lion!”

I asked Meredith if she’d ever attracted any lions with her playbacks. It turns out that she does get some lions every now and then with these exercises, but the scariest and most dangerous reaction she has experienced has been that of elephants.

If there is ever a playback in a site which is already occupied by a herd of elephants, Meredith told me she will not play the roar as long as they are present. She’s had them charge the car at the sound of the roar more than once. Other animals’ reactions are nothing compared to the elephants’ – even a little Thomson’s gazelle, who typically will stay in the area for the duration of the playback, but evacuate in the long-run.

Lacey was interested in working with Meredith during one of our drone flights in order to film the wildebeests’ reaction to the threat of predation. So, this past weekend, that’s precisely what we did.

We flew above the herd, making sure to capture Meredith in the field of view as well, so that, upon reviewing the footage, we could determine how much distance the wildebeests put between themselves and Meredith in response to the roars.

The habitat type we filmed in was a dense woodland, quite different from our typical grassland or savanna. It is interesting to see that, even before Meredith began the playback, the herd had already formed a torus around her vehicle. Collectively, the herd stood their ground and remained vigilant throughout the duration of the recording. A few individuals would have sudden panicked behaviors, running through the herd, but outside of that, the wildebeests remained still.

This is similar to what they do when the threat of predation is real, and the predator is alive and well, directly in their line of view. We have observed herds forming shoulder-to-shoulder lines facing the lion, cheetah, or hyaena in front of them and either following them if the predator was walking or diligently watching if the predator was standing still or bedded.

One of the more striking predator responses was one that we witnessed this morning: A herd of over 1000 wildebeests was travelling in a linear fashion, about 4 or 5 animals across the line, when one spotted hyaena popped up from the grass. The individuals in the front of the line stopped and perked up, watching for the hyaena’s next move. After a tense pause, the leading ‘beests all uniformly changed direction, steering completely away from the hyaena, and the entire herd followed. It seems that there was a mutual agreement between predator and prey at that moment, as the hyaena walked down the hill in the other direction.

The reason that this predator response is relatively striking is that it was in reaction to only one hyaena – and on top of that, one hyaena that was sitting still. The herds we have observed have barely batted an eye at an entire clan of hyaenas 100m away, or one hyaena running through the herd itself. There are a number of factors that could have influenced this behavior, including the height of the grass and time of day – factors which can play to the predator’s advantage.

It will be interesting to see if we can capture any more behavior like this in our ground-truthing work today and tomorrow! We are especially grateful to Meredith Palmer for being a part of this and helping us out with studying the wildebeests’ predator response.

– Jazmin

Feelin’ Like A Million ‘Beests

The wildebeests are still spread out across Serengeti; in the past week, we’ve seen herds of tens of thousands in the western corridor, near Ndutu, and on the way to Fort Ikoma.

The ‘beests and their striped counterparts are migrating through various habitats, including tall, and short-grass plains, open woodland, and riparian forests.

Our first sighting of one of these monster herds was near Turner Springs, where we joined our friend, photographer Daniel Rosengren to track lions for the Serengeti Lion Project. We were at the top of a hill trying to get a signal from one of the nearby radio-collared lions when Daniel noticed a cloud of dust in the distance and said, “That must be the migration right there.” Lacey and I lifted our binoculars to see a large mass of grey Artiodactylans moving slowly through the woodland, like a shadow cast by a drifting cloud.

When we drove down the hill and toward the herd to get a closer look, the sight was even more amazing as the wildebeests covered the Serengeti floor for miles left and right.  It was an incredible sight to see, such a massive number of animals sharing one space, moving  as one unit. We could hear the voices of both wildebeest and zebra alike, moo-ing and shrieking in conference with one another.

The herds are moving quickly, and we’ve got more potential satellite photos coming up – hopefully they’re not moving so quickly that we miss them!

– Jazmin

Hunt

Lately we’ve been lucky enough to witness some pretty incredible predator-prey interactions. The most exciting of them has been a cheetah hunt!

After a day of working on ground-truthing for satellite imagery, Lacey and I were on our way back to Naabi gate from Gol Kopjes when I spotted a cheetah walking toward a herd of wildebeests. Lacey noticed that the cheetah seemed to be intentionally aggravating the herd, as they formed a front line, all individuals refusing to look away from the cat.

There were moments in which the cheetah seemed to be taking a leisurely walk that just happened to be parallel to a herd of palatable ungulates. Yet, as the wildebeest kept watching, the cat would turn toward them, exciting them even more.

We watched the cheetah continue in his instigating, and spotted another individual behind him, which was limping. Upon sighting the second cheetah, their collective presence grew significantly more intimidating. The leisurely walk of the first cheetah suddenly took on a new intent. Although I did not see any gazelle in that moment, it became clear that these two were on a mission.

The cheetah suddenly bolted into the onlooking wildebeests, sending them in a frenzy, running for their lives. The herd kicked up a dust storm in their evasion of the oncoming predator while the second, limping cheetah looked on as helplessly as Lacey and me.

The hunt was over in seconds: as long as the cheetah could keep up its top speed of 103km/hr (about 64 mph). It ended in no reward, and the feline hunter walked away in his original direction, parallel to the herd, exhausted.

This is what we had been hoping for! The herd’s predator response in a high-intensity situation is very intriguing, as they always make sure that there are some individuals watching the threat at all times. It is also interesting that, even before the cheetah showed any signs of hunting, that the wildebeest recognized it as a threat, as cheetahs primary search image is gazelle. Perhaps anything cat- or human-like means “threat” to them.

We wrapped up the day with a rare sighting of an aardwolf soon after, and a golden jackal, which is less common than the silver-backed jackal.

All in all, it was a great day. Next step: catching one of these hunts on satellite.

– Jazmin

Predators and Satellites

Camping was a success!

There were plenty of wildebeest herds around the short grass plains to do behavioral observations on and we shared out campsite with a variety of species, ranging from East African springhares to Masai giraffes. The wildebeest also mixed with Plains zebra, Coke’s hartebeest, and Thomson’s gazelle, both as they grazed and commuted between optimal feeding areas.

During our stay, we were able to record some herd responses to predators like spotted hyaenas and African lions. In the daytime, the wildebeest don’t seem to be concerned about the presence of hyaenas, who are either resting or commuting alone. Thus, we’ve been conducting more morning and evening observations in hopes of  spotting a clan of hyaenas hunting! I’m sure then the ‘beests will have a different response.

For the African lion, on the other hand, the wildebeests are sure to keep their distance. Perhaps, because this Felid is much bigger than its Hyaenid sister, the wildebeest perceive the sight of even one lone resting lion as a threat.

In other news, the wildebeest are still set on grazing in Serengeti’s southern plains. The herds consistently occur in large numbers in this area, so this allows us an illusion of predictability as we gear up to collect satellite imagery. Our friends in the Serengeti Lion Project have been kind enough to conduct predator surveys for us at the time we collect the satellite data. This will give us more insight on herding behaviors and movement on a large scale. Based on the locations of the predators, we will then have context for herd behavior we observe via satellite.

The elements that need to be in place for data collection via satellite include millions of wild gnus and weather – neither of which are in our control. Even still, we are hopeful that we’ll be able to get the perfect shot soon. Fingers crossed!

– Jazmin & Lacey

 

South-Bound

Lacey and I are getting into more of a routine now that it’s just us and a little self-drive Land Rover.

We try to go out early in the mornings, when the wildebeest are awake, typically either walking or grazing. By noon, it gets a bit too warm for them to be very active, so that is the time at which most of the ‘beests are sleeping, and when Lacey and I typically head back home. Upon reaching a herd we conduct behavioral observations, and collect other data specific to the herd we encounter.

In the last week, zebra and wildebeest have flooded the southern plains near Naabi gate (southern entrance to Serengeti through Ngorongoro Conservation Area, NCA), along with Thomson’s and Grant’s gazelle, and even the occasional silver-backed jackal. As we cruised through the short grass, it seemed as if there were no end to the sea of ungulates. Now, only days later, the herds have completely disappeared.

It’s amazing how quickly such a massive amount of animals can move!

The herds are moving south, toward Oldupai – heading over the park border into NCA. They are deterring from their traditional route, as, at this time of year, they are expected to be moving northwest through central Serengeti into the western corridor. Rainstorms have not held back near Seronera so we are hoping that the wildebeest will have a change of heart and venture northward.

The herds we observed today were particularly strange in their predator response, interestingly enough. So far, we’ve witnessed herds create a torus shape around predators – a donut-shape with the predator in the center – mostly in response to hyaenas, but they’ve even done it to us as we sat in our previous Land Cruiser.

Today, however, we watched about 5 individual hyaenas, each in close proximity to the herds on different occasions – one even ran through a line of travelling wildebeest – and yet the wildebeests had no stress reaction. They simply watched the hyaena run through the herd, apparently not even thinking of running.

Contrary to popular belief, hyaena are not purely scavengers. This matriarchal species often hunt in highly organized packs, achieving higher success rates than the African lion. The wildebeest have plenty of reason to be afraid this bone-crushing animal, yet they showed no signs of concern.

Perhaps they can tell the difference between a threatening hyaena and one that simply commuting through its territory? One hyaena was running along with its pup in its mouth – could they tell that that particular individual was momentarily harmless, due to the presence of its helpless young? Could the time of day (early afternoon) have played a part? Not only are the wildebeest lazier at this time, but so are predators, the majority of them (if not all) being nocturnal. We are not sure, but it is curious that several different herds on this same day showed no response to the presence of a predator.

The drive from our TAWIRI guest house to Ndutu, where the wildebeest are currently passing through, is just over an hour and a half, a bit much for everyday travel. In order to avoid having to make this long trip every morning, we’re going to camp in southern Serengeti, which will allow us to remain close to the wildebeest and maximize field time. We will be accompanied by two Serengeti predator researchers, so during this time we also plan to get more information on locations of large predators, in order to better understand movement of the herds in terms of predator-prey interactions and environmental factors they could be collectively responding to.

Hopefully the wildebeest don’t disappear on us again – south or bust!