Culture

The Killer Lions of Tsavo

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Pride of Tsavo lions
Lions in Tsavo National Park, Kenya

Humans are not at the top of the food chain. Throughout history, big cats have sometimes made a meal of us [5]. Although lions typically prefer large prey like buffalo and wildebeest, a 5000-year-old Egyptian cosmetic palette depicting lions eating the fallen on the battlefield tells us that lions have been known to prey upon people for a long time [5]. But one episode of human-lion conflict at the end of the nineteenth century really captured the popular imagination. The “man-eating” lions of Tsavo (SAH-vo) terrorized the Tsavo region of Kenya for nine months in 1898 [1-7] and may have preyed on humans unnoticed for several years prior [5]. The man who killed them, J. H. Patterson, was hailed as a hero [4, 5]. He estimated that the lions killed as many as 135 people [1-3, 5-7].

The Lions, the Colonel, and the Railroad

The lion’s roar was such that the very earth would tremble at the sound, and where was the man who did not feel afraid?

From epic poem gifted to Col. Patterson by his work crew [4]

The British Colonial Office was building a railway from the port of Mombasa, Kenya, to Nairobi, which was then in Uganda [3-5, 7]. Then they reached the Tsavo River. Tsavo means “place of slaughter” [3, 4]. Building a rail bridge over the river proved much harder than anticipated, at first mostly for engineering reasons such as locating the right type of stone locally [4]. So they hired a civil engineer to lead the Tsavo bridge project: Colonel J. H. Patterson [2-6]. Construction began in March 1898 [2, 4]. Very soon, he encountered a problem his education did not prepare him for.

“Our work was soon interrupted in a rude and startling manner. Two most voracious and insatiable man-eating lions appeared upon the scene, and for over nine months waged an intermittent warfare against the railway and all those connected with it in the vicinity of Tsavo,” Col. Patterson explained in his 1907 book The Man-Eaters of Tsavo and other East African Adventures [4]. They were large male lions without manes, working together, which is atypical behavior for lions. They attacked at night, tearing through the protective walls of thorns, called bomas, that the rail workers built around their camps, and then dragging sleeping people from their tents off into the bush [4].

Col. Patterson considered it his responsibility to do something to protect his work crew, so he turned everything he’d learned from his big game hunting hobby toward killing the Tsavo lions [4]. But the lions managed to evade him for months. They never struck the same encampment twice in a row, making it impossible for him to stake them out [4]. At first the lions were easily kept at bay by fire and loud noises, but they became less and less afraid of human things as time wore on [4]. The only thing that seemed to deter them was being out of their reach, so the crew went on strike December 1st to be allowed to build elevated sleeping platforms [4]. It was this work stoppage that finally brought the slaughter to international attention [5].

J. H. Patterson and Tsavo lion
Col. Patterson with first Tsavo lion – Photo from Field Museum on Wikimedia Commons

Later that month, however, Col. Patterson finally caught a break. He baited the lions with the corpse of a donkey that one of them had already killed when attacking a camp [4]. He hoped that one or both lions would come back to finish eating their kill, so he had a rickety platform built to keep watch on [4]. The lion did return, but decided to stalk Col. Patterson instead [4]! Col. Patterson managed to shoot the lion dead before being killed himself [4]. A couple weeks later, he baited the second lion with a trio of goats and killed it as well [4, 5]. Both lions were over 9 feet (2.7 m) long [4, 6].

Col. Patterson detailed the deaths of 14 victims in his book but put the total at “no less than twenty-eight Indian coolies, in addition to scores of unfortunate African natives of whom no official record was kept” [4]. The railroad office in London recorded the deaths of 28 railroad workers who fell prey to the Tsavo lions [3, 5]. Col. Patterson later specified that 107 locals were killed, which is how we get the 135 number [5]. However, research conducted at the Field Museum many years later estimated that the lions actually consumed about 35 people during their lifetimes [1, 2]. Human flesh made up about 30% of one lion’s diet and 13% of the other’s [1].

Why did the lions of Tsavo become man-eaters?

Patterson didn’t give much attention to this question, giving only such dismissive explanations as the lions’ incredible savageness and “sheer insolent contempt for man” [4, 6]. In his time and place, animal behavior and cognition were not front of mind. The lions killed humans because they were evil, and that was that [4]. But we have learned a lot about why animals do what they do in the past 125 years. Researchers have come up with several theories of what motivated the lions of Tsavo to kill and eat humans.

Bad Teeth

In the late 1990s, researchers examined the skulls of the Tsavo man-eaters and discovered significant dental problems [1, 2, 5]. The first lion Col. Patterson killed had a severely broken canine that exposed the tooth pulp, a root tip abscess, and three missing incisors [1-3, 5]. The scientists believed the injuries happened early in life because the lion’s jaws had changed shape from the asymmetry of its teeth [1, 5]. They hypothesized that the injuries were caused by a kick or strike from the horn of the lion’s prey and may have made it difficult for him to catch the tough-skinned wild animals lions typically prey upon [1-3, 5]. He may have made a habit of hunting slow, squishy humans as a matter of necessity [1-3, 5].

Lion skull with broken teeth
Severe dental trauma of Tsavo man-eater – Photo from Peterhans, Julian, & Gnoske [5]

The second lion had minor dental injuries: two broken teeth, one an old injury and one new [5]. These type of dental injuries are common among wild lions, though, and the researchers didn’t think they were enough to change the lion’s behavior [1, 5]. If the two lions already hunted together, however, the second lion may have taken his friend’s lead in hunting new prey [5].

Field Museum scientists studied the wear and tear patterns on the Tsavo man-eaters’ teeth and concluded that they had not been crunching up bones like wild lions normally do [1, 2]. Their teeth looked more like those of zoo lions [1, 2]. This supports the idea that the two lions were eating a softer diet [2]. But while there is a wide belief that lions and other big cats who eat humans are usually old, sick, or injured, statistically that is not the case [5]. A study in 2014 of the skulls of lions that preyed on humans and/or livestock, a.k.a. “problem lions,” found that most were healthy and in the prime of their lives [5]. Those that were debilitated usually had leg injuries that made it difficult for them to chase down and grasp prey, rather than tooth problems [5].

Cultured Beasts

The idea that non-human animals have their own cultures might seem strange, but many species have been shown to exhibit differences in behavior between subpopulations that can only be explained as knowledge passed through the generations [5]. Tsavo lions have some of these cultural differences that set them apart from neighboring lion populations [5, 7]. The lions of Tsavo live in prides about half the size of Serengeti lions, with only one male and up to ten females [7]. There is never more than one male in the pride in Tsavo [7]. Tsavo lions are also known for preying on humans [5, 7].

Humans may have taught the lions this habit [5, 7]. For centuries, Arab slave traders used the same routes through Tsavo to the port at Mombasa [5, 7]. Along the way, many of the slaves would die from sickness or maltreatment [5, 7]. The dead and dying were left where they fell [5, 7]. Lions are known for being predators, but they will scavenge, too [5, 6]. They likely learned that humans were a good food source by feeding on the bodies of those slaves [3, 5, 7].

Through the generations, the lions remembered that humans are prey. The Kenya-Uganda railway was built along an old caravan path that had probably provided the lions of Tsavo with much human and livestock prey in the past [5]. When thousands of largely unprotected workmen appeared on the path, it may have seemed like a dinner invitation to a pair of young lions.

Changing Environment

Some big changes in the lions’ environment could have prompted them to change their hunting behavior. For one, lions are ambush predators, like almost all felines, so they prefer to hunt from within vegetation or other natural cover [5]. The Tsavo region is especially hot and dry, with the vegetation growing as tangled thornbush called “nyika” [4-6]. The ivory trade significantly reduced the number of elephants in the region by the 1890s, and fewer elephants led to more vegetation [5]. In his book, Col. Patterson describes literally crawling through the nyika looking for the killer lions [4]. These thickets made it easier for the lions to ambush the rail workers [5].

The pair of lions’ interest in the rail workers may have stemmed from environmental changes as well. Since the 1860s, Tsavo had been suffering from severe drought and famine as well as epidemics of cholera and plague [4, 6]. This reduced the population of wild prey, but it also led to large numbers of dead and dying humans left in the wilderness for the lions to eat instead, training them on the new food source [6]. Exacerbating the lions’ plight was a dire epidemic of rinderpest, a deadly cattle disease that also affects many wild herd animals [3, 5-7]. Rinderpest is native to Asia and arrived in Africa in 1887 through infected cattle from India [6]. The first African rinderpest epidemic killed 95% of Ethiopia’s cattle [6]. Buffalo, favorite prey of lions in Tsavo, are particularly vulnerable [5]. With the lions’ usual prey depleted, the switch to humans may have been a simple and practical decision.

Visit the Lions of Tsavo

Author with lions of Tsavo at Field Museum
Selfie with the lions of Tsavo – Photo by author

After killing the Tsavo man-eaters, Col. Patterson skinned them both and turned them into trophy rugs [2]. In 1925, he sold the skins to the Chicago Field Museum, where they were mounted as taxidermy specimens and displayed in a diorama [2, 3]. They are still on display with the mammals of Africa in the Rice Gallery [2]. I’ve been to see them myself, and I highly recommend visiting the Field Museum if you can.

You can also visit Tsavo National Park in Kenya and see the living lions of Tsavo that still roam the same land Col. Patterson’s man-eaters once stalked. It is one of Africa’s largest game reserves, sporting about 675 lions within the ecosystem as well as a wide variety of other wildlife. [7]

Works Cited

  1. DeSantis, L. R. G. and Patterson, B. D. (2017). Dietary behaviour of man-eating lions as revealed by dental microwear textures. Scientific Reports, 7, 904. https://www.nature.com/articles/s41598-017-00948-5
  2. Field Museum. (2018, February 10). Tsavo lions. https://www.fieldmuseum.org/blog/tsavo-lions
  3. Newbart, D. (2004, August/September). Mystery of the man-eating lions. National Wildlife.
  4. Patterson, J. H. (1907). The man-eaters of Tsavo. The Lyons Press: Guilford, CT.
  5. Peterhans, K., Julian, C., and Gnoske, T. P. (2001). The science of ‘man-eating’ among lions Panthera leo with a reconstruction of the natural history of the ‘man-eaters of Tsavo.’ Journal of East African Natural History, 90(1), 1-40. https://doi.org/10.2982/0012-8317
  6. Tomasula y Garcia, A. (2014) The lions of Tsavo: man-made man-eaters. Western Humanities Review, 68(1), 195-200.
  7. Tsavo National Park. (n.d.). Tsavo National Park lions. https://www.tsavonationalparkkenya.com/tsavo-national-park-lions/

Published July 23rd, 2023

Cat Care

In Search of the Best Cat Food, Part II: Wet or Dry?

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White cat eating dry cat food
Image by Deedee86 from Pixabay

There is a head-spinning variety of cat foods out there, but the most basic distinctions can be drawn based on moisture content. Dry cat food, the familiar dehydrated kibble, contains 6-10% water (1, 2). Semi-moist food is 15-30% water (2). Canned food has a moisture content of at least 75% (1, 2). Generally speaking, the higher the moisture content, the higher the price and the lower the convenience, so dry food is a very popular choice. But is it the best choice for our cats’ health?

Because kibble is already dehydrated, it doesn’t dry out if left in the bowl for long periods of time, so it lends itself to the convenience of free-feeding. Cats usually like to eat lots of small meals, and let’s face it, people like to be lazy, so this arrangement is often mutually agreeable. We’ll discuss in another part of this series why free-feeding may not be ideal, at least for some cats, but regardless it is often what busy people resort to, and dry food makes that easy. Dry food can also be bought in bulk and will last a long time if stored properly in a cool, dry place. And, again, it’s usually cheap.

Human concerns are not the only reason why someone would feed their cat dry food, however. It has long been thought that kibble helps clean cats’ teeth, preventing and/or treating dental disease. Veterinarians sometimes recommend it for this purpose (3). The idea is that chewing the hard bits of kibble mechanically scrapes the teeth clean of plaque buildup (3), and there has been some scientific evidence supporting the idea that dry food does, in fact, prevent periodontal disease (4). More widely, however, the evidence does not support the idea that dry food cleans cats’ teeth, and there is good reason why it wouldn’t (3).

As mentioned in part one, cats are obligate carnivores. They evolved to eat meat exclusively. As such, their teeth are made for biting and tearing, not chewing (3). Plant matter includes tough cell walls that need to be broken down, so animals that are meant to eat plants do a lot of chewing (3). Carnivores just bite off manageable chunks and swallow them whole (3, 5). That is usually what cats do with kibble. They swallow it whole. Sometimes they bite the kibble, but when they do, the hard but brittle kibble shatters on the biting edges of the teeth and doesn’t do anything to scrape the teeth clean (3, 6).

Yawning gray tabby cat
These chompers aren’t for chewing – Image by Martina Misar-Tummelsthammer from Pixabay

As far as the nutrition of dry food goes, it isn’t great news, either. Dry cat food is typically high in carbohydrates, on average 35-50% by calories (6). Cats neither need carbohydrates, nor can they digest them well, due to their biology as obligate carnivores. They need a diet high in animal protein with a moderate amount of fat (see part one).

Not all dry foods are created equal, of course, but even grain-free dry foods can still be high in carbohydrates if they simply replace grains with potatoes or peas (6). It’s also common for much of the protein in dry food to come from plant matter, but plant proteins do not contain all of the amino acids that cats need (6). The missing nutrients are supposed to be added back in, otherwise the food won’t meet required nutrition standards, but pet nutritionists are still learning exactly what cats need.

With all that being said, is dry cat food just the worst? Well, no, trying to make a cat vegan or feeding them a diet of human food would probably be the worst. When I looked up veterinarian opinions on whether dry or wet food was better, there were mixed opinions. Some were adamant that cats should only be fed canned/wet food (i.e. 3, 6). Others said it didn’t matter (i.e. 5), or it depended upon the cat. I didn’t come across anyone who was a staunch defender of dry food, but there were definitely professionals who had no quarrel with it. I’ll touch on semi-moist food at the end, since it is kind of a weird middle ground, but first let’s take a look at wet food.

Wet food, which as far as I know only comes in cans, can vary in quality but is always notable for its high water content, up to 84% (7). Cats should consume about 20-70 ml of water per kg of body weight per day (8). But cats are descended from Felis lybica, a desert wildcat, so they have a low thirst drive. They tend to obtain most of their water from their food. Prey would normally contain 70-75% water (6). Studies have demonstrated that cats can avoid dehydration without drinking any water at all as long as they are given food with at least 67% moisture content (7, 9, 10).

Of course, a cat should never be without fresh water, but it goes to show just how important dietary water is to cats. Canned food replicates the water content of prey well and helps keep cats hydrated. This prevents urinary and kidney problems, which are common in cats and can be very dangerous (3, 5, 6, 11). Cats fed dry food will drink more water, but they don’t drink enough to compensate, resulting in dehydration and possibly health problems (6).

Canned food is usually higher in protein and made with more animal ingredients than dry food, although cheap, low-quality canned food may still be more plant-based. Reading labels is important, even though pet food labels are not as informative as human food labels. When doing so, keep in mind that the amounts of nutrients are listed as percentages, so the more moisture a food has, the less of other nutrients it may seem to have. Some math may be required to determine the comparative dry weight nutrient content.

Calico cat drinking from garden pool
Cats need to get most of their water from their food – Photo by Dorothea OLDANI on Unsplash

Canned food isn’t perfect. A positive correlation has been demonstrated in cats between hyperthyroidism and eating canned food (5, 12). The cause of the correlation is unknown, although there are a number of theories, one of which suggests that the actual cause is a fire-retardant chemical present mostly in indoor fabrics, not the food (13). However, until we know more, all that can be said for sure is that a correlation has been found.

Semi-moist food comes in plastic pouches or trays, which often aren’t recyclable, so I have to say it isn’t my preference just because of the environmental impact of all that plastic. However, semi-moist food provides cats with quite a bit more water than dry food while not going bad in the bowl as quickly as wet food, so it can be a good compromise between a cat’s need for dietary water a human’s busy schedule. Semi-moist food tends to feature animal ingredients as the main event, providing more protein and a more species-appropriate dish than many dry foods (1). Those pouches and trays are pre-portioned and easy to dump in the bowl, but do be careful that the portion it comes in is right for your cat if you choose this option.

Because cats are the domesticated version of a desert animal, dietary water is extremely important. If for this reason and no other, canned food, ideally a high-quality, meat-forward one, would be the best option. Not everyone can afford the most expensive, gourmet canned food, however. Cheap canned food or semi-moist food is still a good option. A 2010 study showed that cats exhibited better urinary health if water was simply added to their dry food (11). We all have to figure out the best plan for ourselves and our cats. If your cat has specific dietary needs, and you aren’t sure how that would affect what form of food would be best for them, it’s always a good idea to ask your veterinarian.

Works Cited

  1. Cornell Feline Health Center. (2017, July). Feeding your cat. Cornell University College of Veterinary Medicine. Retrieved here.
  2. Feuer, D. (2006). Your Cat’s Nutritional Needs. National Research Council.
  3. Kelsey, A. (2014). 6 reasons why dry food does not clean your cat’s teeth. Cat Behaviourist. http://www.catbehaviourist.com/blog/6-reasons-dry-food-clean-cats-teeth/
  4. Watson, A.D. (1994). Diet and periodontal disease in dogs and cats. Australian Veterinary Journal, 71(10), 313-318. DOI: 10.1111/j.1751-0813.1994.tb00905.x
  5. Barchas, E. (2017, July 31). Ask a vet: Would you recommend wet food or dry food for cats? Catster. https://www.catster.com/lifestyle/wet-dry-cat-health-canned-food-kibble-cats-ask-a-vet
  6. Pierson, L.A. (2016, November). Feeding your cat: Know the basics of feline nutrition. CatInfo.org. https://catinfo.org/
  7. Case, L.P., et al (1995). Canine and feline nutrition. Mosby, Inc.
  8. Ackerman, N. (Ed.). (2016) Aspinall’s complete textbook of veterinary nursing, 3rd edition. Elsevier.
  9. Prentiss, P.G., Wolf, A.V., Eddy, H.A. (1959). Hydropenia in cat and dog. Ability of the cat to meet its water requirements solely from a diet of fish or meat. American Journal of Physiology, 196(3), 625-632. https://doi.org/10.1152/ajplegacy.1959.196.3.625
  10. Caldwell, G.T. (1931). Studies in water metabolism of the cat. The influence of dehydration on blood concentration, thermoregulation, respiratory exchange, and metabolic-water production. Physiological Zoology, 4(2), 324-359. Retrieved from https://www.jstor.org/stable/30151145
  11. Waltham Petcare Science Institute. (n.d.) Cats benefit from increased dietary moisture. https://www.waltham.com/news-events/nutrition/cats-benefit-from-increased-dietary-moisture/5548/
  12. Edinboro, C.H., et al. (2004). Epidemiologic study of relationships between consumption of commercial canned food and risk of hyperthyroidism in cats. Journal of the American Veterinary Medical Association, 224(6), 879-886. DOI: 10.2460/javma.2004.224.879
  13. Hofve, J. (n.d.) Feline hyperthyroidism. Jackson Galaxy. https://www.jacksongalaxy.com/blog/feline-hyperthyroidism/

Published July 12th, 2020

Updated November 21st, 2020