Big, Mean, & Nasty

Slide1

I recently gave a talk at the Arusha-based Interpretive Guide Society – a really cool group of people interested in learning more about the natural history of Tanzania’s places and animals. I’ve taken a few clips from the presentation that describe in a bit more detail how lions bully their competitors.

Looking at the photos above (all nabbed from the internet), how many of you would like to be a wild dog? A leopard? A cheetah? There’s no doubt about it – lions are big, and mean and nasty. If you are any other carnivore species in the Serengeti – or across Africa, lions chase you, steal your food, even kill you. So what do you do? How do you survive? That’s essentially what my dissertation seeks to answer. How smaller “large carnivores” – hyenas, leopards, cheetahs, and wild dogs — live with lions. Under what circumstances do they persist? Under what circumstances do they decline or even disappear?

There are a handful of ways in which these species interact, but what I’m most interested in is aggression and it’s repercussions. As the above pictures suggest, lions tend to dominate aggressive interactions.

Slide2

The relationship between lions and hyenas is one that has wormed its way into the public psyche through nature documentaries such as “Eternal Enemies.” While such movies play up the frequency of such interactions, they certainly do happen. Lions not only kill a number of hyenas, but steal their hard-won kills. Dispel any notion of lions as some noble hunter — they in fact steal a lot of their food from other carnivores. In fact, research from Kay Holekamp’s group in Masaai Mara  indicates that lions can suppress hyena populations just because they steal food from them! It’s actually a similar story for wild dogs – lions kill wild dogs too, but since wild dogs expend so much energy hunting, that if lions steal just a small fraction of the food that wild dogs catch, wild dogs simply cannot recover. They would have to hunt for more hours than there are in a day to make up for this caloric loss.

It doesn’t stop there. We don’t know how much food lions steal from cheetahs or leopards. We also don’t know how often lions kill leopards, but lions kill cheetah cubs left and right. Studies from Serengeti indicate that lions may be responsible for up to 57% of cheetah cub mortality!

Slide3

So how do hyenas, wild dogs, leopards, and cheetahs survive? Well, that’s what I’m trying to figure out. But what I can tell you is that not all of these smaller carnivores sit back and take their beating quietly. Take hyenas. They’re about 1/3 the size of a lion, but they live in groups. Big groups. Much bigger groups than lions. And if there are no male lions around, if hyenas have strength in numbers, they can steal food from female lions, and even kill their cubs. While leopards don’t live in groups, they can easily kill (and eat!) a lion cub that has been hidden while mom is away hunting.

Unfortunately, what we don’t know is whether this reciprocal aggression by leopards and hyenas has any measurable affect on lion populations, and whether it’s this aggression that allows hyenas and leopards to coexist with lions. The cameras behind Snapshot Serengeti will provide the first-ever map of leopard and hyena distributions within the long-term lion study area – by comparing lion reproductive success (which we know from >45 years of watching individually identified animals) to leopard and hyena distributions, we can see if lions do better or worse in areas with lots of hyenas or leopards – and whether this is due to getting less food or producing fewer cubs.

Slide4

What about cheetahs and wild dogs? Even though wild dogs, like hyenas, live in groups, there’s no evidence that this helps them defend themselves or their kills against lions. And cheetahs, well, there’s no record of them killing lion cubs, but who knows?

So how do these guys live with lions? To be honest, wild dogs don’t tend to do very well in places with lots of lions. In fact, it’s generally believed that wild dogs have failed to recolonize Serengeti, despite living *just* a few km from the border, because lion populations are so high. For a long time, researchers and conservationists believed that cheetahs also couldn’t survive in places with lots of lions – but that perception is beginning to change, due, in part, to data coming in from Snapshot Serengeti! It seems that cheetahs not only do just fine in reserves with lots of lions, but use the same areas within the park as lions do. I have a sneaking suspicion that how cheetahs use the habitat with respect to lions, how they avoid encountering lions even though they’re in the same places, holds the key to their success. Avoidance, combined with habitat that makes avoidance possible (read: not the short grass Serengeti plains you see below).

Slide5

I’ll write more about avoidance and habitat another day. In fact, I’m currently revising a paper for a peer-reviewed journal that addresses how cheetahs and wild dogs differ in the ways they avoid lions – if accepted, it will be the first appearance of Snapshot Serengeti data in the scientific literature! I’ll keep you posted…

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About ali swanson

I'm an ecologist studying how large carnivores coexist. I spend way too much of my time trying to stop hyenas and elephants from munching my camera traps!

10 responses to “Big, Mean, & Nasty”

  1. Ben says :

    It’s = It is
    its = possessive

    Come on, Ali – no sloppiness allowed!

    • Margaret Kosmala says :

      Thanks. Fixed.

      Ali gets a sloppiness pass when she’s rushing to finish up her field work, pack, apparently giving talks in Arusha(!), and trying get the field assistants set up to continue the research while she’s gone. We’ll take her pass away when she gets back to the U.S. 🙂

  2. Simon K says :

    Fascinating subject, Ali. Please, do keep us posted on your findings.

  3. Darlene says :

    This is all so very interesting. Thank you for sharing your pics and knowledge. Love to follow you.

  4. matthewsted says :

    Reblogged this on matthewsted and commented:
    Sad! Where are we going?

  5. ettinacat says :

    What I was told in the Big Cat Diaries series is that cheetahs avoid lions by:

    a) hunting predominantly by day, when lions prefer to sleep

    b) hunting in open country, while lions prefer shade

    Is that accurate? Is it more complicated than that?

    • ali swanson says :

      Well, it’s complicated.

      So, you’re absolutely right that a) cheetahs hunt primarily during the day, when lions are less active, and b) hunt in open country, where lions aren’t very good at catching things. The questions then become 1) why cheetahs show different patterns, and 2) whether these patterns are costly for cheetahs.

      Say that cheetahs were better nighttime hunters than daytime hunters, but avoided hunting at night specifically to avoid lions. That would be costly in the sense that they weren’t able to maximize their skills, and they’d have less energy to focus into reproducing. That’s what I refer to avoidance, and I think it has negative population-level effects. In contrast, if cheetah were simple better daytime hunters, then these natural differences would reduce the amount of lion-cheetah conflict without hurting cheetah populations. This is what I call partitioning — and it would allow cheetahs to reduce risk of aggression by lions without negative population-level effects.

      One of the ways to identify whether cheetah behavioral patterns are avoidance vs. partitioning is to see how they change in areas with lots of lions to areas with few or no lions.

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