Lion Predation

[TheHyenid76]

Lion predation on chimpanzees

Information is from Dr Toshisada Nishida's incredible book 'Chimpanzees of the Lakeshore: Natural History and Culture at Mahale' where he describes lion predation on chimpanzees.

*This image is copyright of its original author

*This image is copyright of its original author

2.9 Predation on Chimpanzees
2.9.1 Lion eats chimpanzees

For a long while, it was believed that aside from humans, chimpanzees had no natural enemies. It is not absolutely inconceivable for an infant chimpanzee to fall victim to a leopard or eagle, but no proof existed that any other animal besides humans ever ate chimpanzees. So far, I have not seen any predator eat a chimpanzee. Regarding other nonhuman primates, I have only once seen a crowned hawk-eagle eating a
red-tailed monkey.

In 1966 Junichiro Itani and Takayoshi Kano observed a group of chimpanzees in the Ugalla region that were wailing in a treetop, probably after being chased there by the lion that Kano inadvertently collided with, head-on (Itani 1979; Kano 1972)!

Takahiro Tsukahara, a graduate student in the Department of Anthropology of the University of Tokyo, furnished proof of such predation, removing any doubt. After two lions were spotted in the vicinity of the Kansyana camp in 1984, the following five years were quiet. At Kasoje, 1989 came in with an ominous roar. In March, Hitoshige Hayaki reported hearing a lions roar in the south sector of M-groups range. After that, Tsukahara, who was on his own in Kasoje, worried that a lion had begun dwelling there. The damage done is described here (Tsukahara 1992).

First, the chimpanzees began to use the hilly section of the groups territory, rather than their usual ranging routes, which made human tracking a burden. Second, the cook and research assistant were terrified of the lion, and so they stopped coming to work early in the morning, as lions are most active then. From the village to camp was about a 1 km trudge through the bush, which these employees now would not take. To Tsukahara, trekking alone in the hills meant grave danger, but waiting on the Tongwe workers meant the research work could not start until noon. This dilemma caused him to lay aside the core of his research for the time being (which was the grooming relationships among adult male chimpanzees), and search for a solution as he investigated the lions next move. He formed a patrol regiment with one of the assistants (who carried a rifle), which included poking around here and there, implementing a painstaking documentation system citing locations of faeces, vocalisations (roars), and pawprints, plus the number of lions, the direction of their movements, and their home range.

The only way that black hairs were discovered in the lions faeces was as a result of the unplanned exertions made by Tsukahara. His intuition told him that those long black hairs were those of a chimpanzee. I ordered him to send me, by airmail, a portion of the hair. As there are other animals at Mahale with black hair, such as blue monkeys and bushpigs, one could not conclude that just because the hair was black it must have belonged to a chimpanzee. I sent the hair samples off to a hair specialist, Haruhisa Inagaki. From his former work at the Japan Monkey Centre, he had accumulated samples of hair from captive animals. He matched the hairs up under an electron microscope and informed me that they were unmistakably from a member of Hominoidea. An electron microscope can discern hominoid (ape and human) hair from cercopithecoid (Old World monkey) from the medulla structure of hair (Inagaki & Tsukahara 1993). Since no human had been killed by a lion around Mahale, the hair must have come from chimpanzees.

That was an exciting bit of news, but not the kind of finding that pleased me on a personal level. Tsukahara was good enough to keep me posted on the movements of some of the chimpanzees to whom I had grown particularly attached: 'Recently, Wasobongo is nowhere to be found' or 'I have not seen Mtwale these days.' As it was not unheard of that some chimpanzees, in particular those females that keep to
M-groups southern sector as their core area, were not seen over a three-month period, I at first did not worry too much about the news. Later, I became gravely concerned because, although I wished these to be cases of temporary absence, it was beginning to look like they were the victims of lions.

2.9.2 At least eight taken as victims

Tsukahara suspected that the last days the chimpanzees were seen and the days that he discovered black hairs or bone in the lion faecal samples would fit the same timeline. After returning to Japan, he paid a visit to the Ueno Zoo in Tokyo ( Japans largest zoo) and fed one of the lions there in order to investigate the length of time it takes for food to pass through the gut after it has been eaten. He found that the shortest duration was 24 hours, while the longest was 60 hours. He also asked Tokyo University morphologist Gen Suwa to run an analysis of the teeth and bone that were discovered with the hair. The teeth and bone samples proved to be stronger evidence than were the hair samples, as Suwa was able to determine the ages of two of the chimpanzees that were eaten from these samples.

Thus, two mother-and-child pairs and two adolescent males, at least six individuals in total, were confirmed as victims of the lions. In the following year, 1990, two more victims were taken. Over two years, I learned of the deaths of three female chimpanzees with whom I had developed relationships over 20 years: Chausiku, Ndilo, and Wantendele. There was also another female victim I had been close to for 17 years, Wasobongo. The motivation and power to go on conducting research on female chimpanzees, as I had done since 1979, no longer resided within me. I forever stopped systematic study of adult female chimpanzees.

It is possible to interpret the significance of these incidents in one of two ways. One consideration is that the lion is an ancient predator of the chimpanzee. The other is that this was a fortuitous accident  lions seldom attack humans, but at times, just as a particular man-eating lion emerges (Patterson 1979), so too can a chimpanzee-eating lion. For now, we cannot draw a conclusion about either, though I believe the former is the case. That is, observations made in savanna woodland such as Kasakati or Filabanga, where there are many lions, show that chimpanzees gathered and dispersed freely within riverine forests, but when moving from one riverine forest to the next, traversing the savannas open canopy forest, they travelled in large parties (Itani & Suzuki 1967; Izawa 1970; Nishida, unpublished observation). Is this arrangement done for anti-predator purposes, in particular against lions? For a long time, as lions were nowhere to be seen around Kasoje, the chimpanzees did not take the appropriate anti-predator counter-measures, highly increasing the possibility of numerous casualties. Almost every behavioural pattern of a chimpanzee is modified by experience after it is born (Chapter 9). Therefore, although the avoidance of lions is innately motivated, chimpanzees need traditions when it comes to coping appropriately with formidable predators. Perhaps the chimpanzees of Kasoje lost this tradition long ago because they rarely met with lions.

Tsukaharas discovery was a landmark in that it clarified the point that when it comes to the social structure of great apes, we cannot ignore the effect of predators.

Let us return to Kasoje. Tsukahara encountered lions three times in the bush. In addition, some of the video crew from Japan also had an encounter with an adolescent male lion early in the morning. All of the assistants in the camera crew were so startled that they fled  after throwing away all of the equipment! The following year Kenji Kawanaka met up with a young male lion in the early morning hours on his way to the mountains and he ran for his life, forgetting the Tongwe proverb that said 'Never show your buttocks to a lion' (that is, do not flee to escape from a lion). Fortunately, the young lion seemed to be satiated, and he emitted only a slight bark.

When I arrived at Kasoje in October 1989, the lion was still on the prowl. At about 4:00 a.m. on 5 November, a lions roar could be heard a few hundred metres west of the camp. After dinner, from about 8:00 p.m. until after 11:00 p.m., close to ten roars could be heard. Chimpanzees who made beds in the Kansyana Valley responded to the roars with what I call the 'fear call', a wispy vocalisation, but after several roars this changed to pant-hoots, and finally, even though they could still hear roars, they stopped replying. Luckily, I never ran into the lion. From 1991 onward, the lion never again showed up in Kasoje.

Key take-aways from this post

• Lions prey on chimpanzees if they share the same habitat
• Lions were likely ancient predators of chimps and Dr Toshisada Nishida believes this is the case
• The Japanese research crew encountered and met with lions
  

Since there are no images of lions with chimpanzee kills, so here are lions with baboon kills

*This image is copyright of its original author

*This image is copyright of its original author

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