A worldwide perspective on large carnivore attacks on humans

Abstract

Large carnivores have long fascinated human societies and have profound influences on ecosystems. However, their conservation represents one of the greatest challenges of our time, particularly where attacks on humans occur. Where human recreational and/or livelihood activities overlap with large carnivore ranges, conflicts can become particularly serious. Two different scenarios are responsible for such overlap: In some regions of the world, increasing human populations lead to extended encroachment into large carnivore ranges, which are subject to increasing contraction, fragmentation, and degradation. In other regions, human and large carnivore populations are expanding, thus exacerbating conflicts, especially in those areas where these species were extirpated and are now returning. We thus face the problem of learning how to live with species that can pose serious threats to humans. We collected a total of 5,440 large carnivore (Felidae, Canidae, and Ursidae; 12 species) attacks worldwide between 1950 and 2019. The number of reported attacks increased over time, especially in lower-income countries. Most attacks (68%) resulted in human injuries, whereas 32% were fatal. Although attack scenarios varied greatly within and among species, as well as in different areas of the world, factors triggering large carnivore attacks on humans largely depend on the socioeconomic context, with people being at risk mainly during recreational activities in high-income countries and during livelihood activities in low-income countries. The specific combination of local socioeconomic and ecological factors is thus a risky mix triggering large carnivore attacks on humans, whose circumstances and frequencies cannot only be ascribed to the animal species. This also implies that effective measures to reduce large carnivore attacks must also consider the diverse local ecological and social contexts.

Fig 1. Spatial distribution of large carnivore attacks on humans collected between 1950 and 2019.

We collected a total of 5,440 attack cases worldwide: 1,337 involved sloth bears Melursus ursinus, 1,047 tigers Panthera tigris, 765 Asiatic black bears Ursus thibetanus, 664 brown bears Ursus arctos, 414 wolves Canis lupus, 403 American black bears Ursus americanus, 282 lions Panthera leo, 205 leopards Panthera pardus, 140 coyotes Canis latrans, 135 cougars Puma concolor, 25 jaguars Panthera onca, and 23 polar bears Ursus maritimus. The maps were produced in QGIS, and the base shapefile layer of world countries was downloaded from Natural Earth (https://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-admin-0-countries/) and do not require credit because of public domain. The data underlying this Figure can be found in S2 Data.

Fig 2. Temporal trends in large carnivore attacks on humans in different regions of the world.

(A) The number of attacks shows a nonlinear increase over the years, as evidenced by fitting the general additive mixed model of the number of attacks-1 as a function of the smoothing factor “year.” In particular, the number of attacks has increased in countries with (B) low CO₂ emissions and (C) a high proportion of agricultural land area. In countries with (D) large forest coverage, the number of attacks in the last several years has decreased. Panels B-D are counterplots representing, respectively, the effect of the interaction between year and CO₂ emissions, % of agricultural land area, and % of forest land area on number of attacks-1 from a generalized additive mixed model. The axes represent the values of the predictor variables, and the interior is a topographic map of the predicted values. The pink colors represent larger predictions and the blue ones smaller predictions. The data underlying this Figure can be found in S2 Data.

Fig 3. Attack circumstances clearly differ by regional income levels on a global scale.

In higher-income regions, attacks mainly involved people engaged in recreational activities, whereas in lower-income countries, attacks primarily involved people carrying out work or livelihood activities. The y-axis shows income levels of the countries where attacks occurred: (1) low income (≤$1,005); (2) lower middle income ($1,006–3,975); (3) upper middle income ($3,976–12,275); and (4) high income (>$12,275) [41]. The data underlying this Figure can be found in S2 Data.

Fig 4. Global spatial distribution (1950–2019) of the main large carnivore attack scenarios.

Predatory attacks are especially concentrated in India and Africa, where felids and canids are primarily involved. The maps were produced in QGIS, and the base shapefile layer of world countries was downloaded from Natural Earth (https://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-admin-0-countries/) and do not require credit because of public domain. The data underlying this Figure can be found in S2 Data.