An article in PNAS by Justin Yeakel and co-rorkers, describes how a group of lions in Tsavo, southern Kenya, gradually began to specialise on feeding on human beings. This was over 100 years ago, when the lions cooperatively hunted down dozens of railway workers. This is the background, as described by Yeakel et al:
“From March to December 1898, a coalition of two male lions (as inferred by paired track marks and frequent sightings), killed 28 laborers and “scores of unfortunate African natives” during the construction of the railway through Tsavo. The death toll was later revised to 135 humans, although the accuracy of this value has been challenged . On December 9, Lieutenant Colonel J. H. Patterson D.S.O., a British officer and engineer, killed lion FMNH 23970 (Field Museum of Natural History) (Fig 1A). The skull evinced craniodental pathologies, including malocclusion of the jaws and a fractured lower right canine (Fig 1B0. On December 29, Patterson killed lion FMNH 23969 (Fig 1C), the skull of which revealed a fractured upper left carnassial (Fig 1D), which is relatively common among lions. Given that the attacks on humans and livestock ceased after December 9 and December 29, respectively, and on the basis of the appearance of each lion (the skins were described as being uniquely scored by thorns), it is almost certain that the lions Patterson killed were those responsible for the human depredations.”
This is figure 1 from the paper. The human skulls in Figure 1E were a traditional burial (by humans, not lions) and samples of them were used as a control for the study of lion bones.
Here’s a tiny picture of Patterson (1867-1947), the lion-killer (he went on to write a successful book about his exploits (“The Man-Eaters of Tsavo” – Edgar Rice Burroughs owned a copy) and there have also been three feature films about the man-eating lions:
Using isotopes from the teeth in the lions’ skills, the authors conclude “these findings not only support the hypothesis that prey scarcity drives individual dietary specialization, but also demonstrate that sustained dietary individuality can exist within a cooperative framework. The intensity of human predation (up to 30% reliance during the final months of 1898) is also associated with severe craniodental infirmities, which may have further promoted the inclusion of unconventional prey under perturbed environmental conditions.”
I think, to be honest, this is a case of the notoriety of the subject matter – man-eating lions – driving publication, rather than the inherent interest of the science or the ecology…