Anne Hilborn

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In my blog I ramble on about various aspects of cheetahs and doing fieldwork that interest me. There is the occasional tangent about academia, but mostly it is cheetah pictures.

By Anne Hilborn, Apr 19 2016 07:16PM

Cheetahs need space. A lot of space.

One of the reasons is to avoid competitors and predators. Lions kill cheetahs cub [1] and hyenas (and occasionally lions) steal their hard earned kills [2] In order to successfully raise cubs and be able to feed themselves, cheetahs need to find areas where there aren’t many lions and hyenas and yet there are gazelles to eat and habitat to den their cubs. Even in Serengeti, no such cheetah paradise exists, at least not in the long term.

The short grass plains of Serengeti

The spatial rhythms of carnivores in Serengeti are largely driven by migrations of herbivores and the herbivore migration follows the rains. Rains can be patchy, habitats are varied, and lions and hyenas focus on wildebeest and zebra while cheetahs love tasty gazelle. Cheetahs exploit the varied nature of the herds and the landscape to spend more time on the edges of herds instead of the thick of things where lions and hyenas hang out [3]. Cheetahs are good at hunting in low prey densities, they especially like male Thomson’s gazelles who are solitary or on edges of the herd [4]. Male gazelle tend to be a bit less vigilant which allows cheetahs to stalk close enough to launch their full on high speed chase. And once a cheetah starts chasing, they have about a 50% chance of success [5]. So being on the edges of herds in low prey density areas is good for cheetahs. There are fewer lions and hyenas and enough prey. But as herds are constantly shifting and moving, this means cheetahs have to move along with them. No area is great for cheetahs at all times of year.

Sheridan chases a lone male Thomson's gazelle. And fails to catch it

Asti with a tasty male Thomson's Gazelle

Cheetahs need space and to be highly mobile in order to find the refuges from other predators. But what happens when they can’t move? This is the case with mothers with very young cubs. Cheetahs give birth in dens which are usually in swampy areas with tall reeds, or in rock outcroppings (kopjes). For two months that the cubs are in the den, the mother is limited in how far she can go in search of prey each day as she has to come back and suckle the cubs. If there are enough prey around to feed her heightened nutritional needs (making milk is energetically expensive) things are dandy. But what if the prey move away? A single cheetah would follow them, no problem, but a mother with small cubs can’t. Instead she will have to make daily trips to find prey. And as new research has shown, it is walking that is energetically costly for cheetahs [6]. So there is a limit to how far mothers can go, if they have to go too far, they can end up abandoning the cubs. Another stressor on mothers is that unfortunately lions also like swamps and kopjes. This is bad news for cheetah cubs as cub mortality is very high (95% born do not make it to become independent from their mothers at 18 months) and 70% of that mortality is caused by lions and hyenas [1].

The search for prey can be exhausting.

Thus because they are tied to the den, mother cheetahs are much more likely to be around other carnivores than cheetahs that do not have such constraints [3]. Most other cheetahs get the hell out of dodge if they see lions, but mothers with cubs in the den can’t, they have to stay near the den to try to protect their cubs if possible. Lions don’t just kill cheetah cubs, they are known to also kill adults, so not only do they pose a threat to her cubs, but also to herself.

Armitage just wanted a nice patch of shade to lie down in, but quickly decided to find alternate shade with fewer lions in it.

A good cheetah mother is one who can manage to den her cubs somewhere they are not discovered and killed by lions (no easy feat that), and manages to feed them and keep them safe as they grow. In this respect, not all cheetah mothers are the same. Research suggests that avoiding lions is a learned skill, and those females who are better at avoiding lions have more cubs that survive [7]. Young cheetah mothers have a lot to learn about where to den cubs so that there is enough food around over two months to feed them and not so many lions. Not all females get the hang of it. Some are a bit thick and don’t seem to avoid predators as well. There is a large variety in quality of mothers. Some are super moms and some are just crap at the whole business. Since lions cause so much cub mortality, the ability to avoid predators may be a driving factor in whether a cheetah is a good mother or not.

Cambazola was a lovely cheetah, but didn't really seem to be bothered by the whole raising cubs thing

While Amarula was a super mom

The moral of the story is that cheetahs need space. They need enough space to find refuges from predators and find food. This is why despite the Serengeti being so large (14,750 km2), cheetahs are pretty sparse on the landscape. There are only so many places where they can avoid ~3000 lions and ~9000 hyenas. It is the size of Serengeti ecosystem that contributes to it being a stronghold for cheetahs. With room enough to avoid other carnivores and a social system that allows them to be very mobile, cheetahs can persist in landscape full of larger predators.

By Anne Hilborn, Apr 18 2016 09:05PM

Cheetahs. They are fast, elegant, and spotted. But that is not enough for some of them. Some of them also rock the mustache. There are lots of variants in the cheetah mustache world.

Most aren't blessed with a mustache at all (and feel grumpy about it)

Some are distinguished

Some are subtle

Some are refined

While some are bad-ass

I never saw a cub with a mustache so it is possible that they develop with age. Both males and females can be blessed with the facial bowtie. And apparently some not naturally fortunate can make up for it with the ever popular Meat Mustache.

By Anne Hilborn, Apr 18 2016 01:18AM

January 2015

Well I am taking a break from updating you all about my travails and adventures in Serengeti from 5 months ago. The reason for this momentous shift is that I have started data analysis and am a wee bit excited about the small victories. The monumental task of actually making scientific sense of the data I collected is going to take a long long time, and there will be lots of steps on that road. One of the first steps that needs doing after coming back from the field is data entry. Of course this doesn’t apply to all those organized/dedicated/technologically blessed souls who enter their data in the field. I came back from Serengeti with 2 ½ books of prey survey data and a modest pile of hunt data sheets. I had entered approximately 10 lines of data while in Serengeti so faced a large amount of grunt work ahead of me. Now some grad students are blessed with the ability to pawn off time consuming and mostly mindless data entry on undergrad students. Theoretically this option was open to me, but I was reluctant to take advantage of it for a couple of reasons. The first reason is that I don’t trust other people with my data. Before vaulting into the dizzying heights of grad school I too toiled entering other people’s data. While I was decently paid, it still was mind numbing and I most likely wasn’t as careful as I should have been. Know how sloppy people (including myself) are when it is not their data, I have severe reservations about trusting anybody with my precious data. The second reason is my handwriting is not as perfect as it should be, making data entry mistakes even more probable. The third is that the hunting behavior data is quite complex, there are a lot of interconnected bits of data, some of which are often missing but can be extrapolated from other bits of data.

All my data! Doesn't look like much.

The ideal person for data entry would be meticulous, patient, careful, familiar with the cheetah project data and my handwriting, be able to ask me lots of questions as they arose, and happy to sleuth for missing data. And most importantly, not be me as I had other things to work on. I am incredibly lucky that such a paragon exists in the person of my mother. Through her heroic labors, all of my hunting data got entered by this morning. I scraped through my databooks for every last scrap and reference to hunting behavior and at the end of it all I had 150 records of predation. Many of these were a record of a hunt that failed, so there were no records of the kill or eat. Other times I came across a cheetah already eating, so I have data about eating behavior but not the hunt. However 150 records in 9 months isn’t bad, especially since in February-April I was collecting demographic data for the Serengeti Cheetah Project, and training Dennis to be the research assistant on the project so had very little time for my own work.

With the 150 records so fresh and so clean in my hands, I did a pivot table in Excel to see which cheetahs I had the most hunts from.

*I know I should have done this in R, but I would have had to learn how, while I already know how to do it in Excel.*

Of those 150 hunts, 44 were successful, making the overall success rate a decent 29%. This is similar to the success rates gotten from past decades of hunting data.

Some of the results were not surprising. The champion with the most number of hunts was Wendi. Since I followed her for 6 days straight, it isn’t bizarre that I had so many hunts, she had 3 hungry and mischievous cubs to feed so had to kill a gazelle pretty much every day. To get 5 gazelle, she hunted 18 times, making her success rate pretty standard.

Wendi, provider extraordinaire

The second most prolific hunters were the group of three adolescents comprising of Laura’s two independent daughters and a random young male of unknown provenance that joined up with them. I considered them fairly useless hunters but it turns out they weren’t so bad. Out of their 15 hunts, they managed to catch something 4 times.

Apollo and Bacchus came in a respectable third as far as number of hunts, but they were quite successful, bringing down prey in 4 of their 12 hunts.

Boke (Studel’s newly independent male cub) attracted some mockery for his hunting skills. In fact he was named (not by me) after a hapless human hunter. And it is true that of the 10 hunts I saw, he only caught something twice. But in fairness, Courtney was just as bad (10 hunts, 2 successes) and she's made it to the ripe age of 11.

Boke gets his stalk and chase on.

The most successful cheetahs with a 66% success rate were Vitalis (6 hunts) and the studly brothers Richard and Armitage (only 3 hunts).

Richard and Armitage, slayers of wildebeest calves

Quite a few cheetahs were fairly useless, none of Brandy’s 4 hunts was successful but she made up for it in cuteness.

To my utter lack of surprise it turned out Bradley and Cooper were worthless on the hunting front. Despite watching them for DAYS, they only hunted 3 times, and failed on all fronts. Those boys were more interested in spooning and armpit grooming than hunting.

A tiny first step has been taken, the road I am on seems remarkably long and dark at the moment, but hopefully I’ll manage to stumble on to the end, ideally doing some halfway decent science along the way. I’ll try to keep you updated as I do.

By Anne Hilborn, Apr 18 2016 12:48AM

October 2014

With the unseasonal rains, the herds of zebra and wildebeest turned up in the Seronera area again. The zebra came first, and suddenly the place smelt like a horse barn. Now I've always considered yearling wildebeest to be the largest prey that cheetahs go for, but an afternoon spent with two young males exploded that idea. These are two young but hunky males that suddenly turned up south of Apollo and Bacchus's territory. They were in long unburned grass and they took advantage of the cover to bring down a zebra, and not a small zebra either, but a 3/4 size one. The next day they were almost obscenely fat, and the when I found them they were sitting on a termite mound, being stared at by a semi circle of wary zebra.

Zebra staring at cheetahs full of zebra

The wildebeest turned up a bit later, providing a bonanza for Apollo and Bacchus. I spent a couple of days with them and learned a bit about their routine. It started with a lot of sleeping. Then at some point they would rouse themselves and start walking slowly towards the river, peeing on every tree that happened to be in their way.

Bonding through coordinated scent marking

. Once at the river a whole cluster of cars would inevitably surround them and I would curse to myself about my blocked view, about animal harassment and any other charge I could think of to lay at the feet of the tourists. However the cheetahs were fairly undisturbed, making their slow way across the river and up to the plains on the other side where they sat and inspected the available wildebeest offerings.

Crossing the main road in Seronera to get to the wildebeest on the other side

I watched them take down an adult wildebeest one afternoon, and a hell of a fight it was. One of them was doing all the hard work at the dangerous front end. The end with the horns and hooves and the real risk of trampling and goring. Meanwhile the other one was nibbling daintily and unhelpfully on a back leg. Eventually he figured his brother might actually need some help, so he moved around and grappled with the front end as well. The wildebeest succumbed fairly quickly after that.

Apollo and Bacchus got to eat a decent amount of the carcass before a hyena came in. They surrendered it without much of a fuss, being pretty fat already.

A nice easy meal for a hyena.

By Anne Hilborn, Apr 18 2016 12:16AM

September 2014, again

There has been a fair amount of unexpected rain, and with the burning done by the parks staff, this has led to incredibly green swards. The gazelle and zebra have flocked to them, making Seronera in August look incongruously like the short grass plains in February.

The high density of prey was good for me because I was short on data on cheetah hunting behaviour in high prey density areas. Usually they are asleep in the long grass with not a gazelle to be seen. Recently, I was meandering around the short green grass of Boma kopjes when I found Cooper.

Cooper surveys the desolate emptiness of Boma Kopjes without Bradley

He contact called a bit, thought about chasing some gazelle, then lay down under a tree to sleep off the sadness. A bold black backed jackal came up to investigate. I was impressed as I have seen cheetahs chase jackals with much determination and joy. In fact they love to chase any of the carnivores that are smaller than them. I blame it on being in the middle of the pecking order, cheetahs have to duck and dive to avoid lions and hyenas, so they take out their frustration by chasing jackals, servals, and anything else that is small and furry.

However Cooper evidently couldn’t care less about the jackal, who having sniffed his full, wandered off.

Bradley and Cooper are very devoted brothers (I have great series of pictures of them spooning and grooming), and finding no Bradley worried me. But I cheered myself with the thought that he was probably out on the shag. Cheetah brothers will sometimes approach females together and sometimes one of them will sneak off to get a mating to himself. The other explanation for his absence was that he was dead. An explanation I wasn’t keen to consider, so I was very very pleased when Dennis found both of them together and fat about a week later.

The other pair of brothers in the Seronera area are Apollo and Bacchus. They may have been godlike once but now they are mangy and cross looking and if it wasn’t frowned upon to rename cheetahs (special cases being made if the cheetah is named after someone you now hate like an ex boyfriend or his mother), I was very tempted to rename them Preserved and Killick after the character in Patrick O’ Brian’s nautical historical novels (which I listen to ad nauseam while on follows). As well as being physically unprepossessing, they display a distinct lack of brotherly affection towards each other that I find troubling.

I once watched Apollo do nothing about Bacchus’s bloody face for hours after eating. Hours I tell you!

Richard and Armitage would never let that happen

Neither would Bradley and Cooper

However recently I found Apollo and Bacchus and there was a gratifying amount of bonding between them and I softened my harsh assessment of their behavior.

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