What happens after death? An international study led by the University of Granada (UGR), involving Ana Mateos and Jesús Rodríguez, researchers at the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), argues that this question, long overlooked by ecology, can help us understand a wide range of processes and offer new perspectives across different disciplines.
The study, published in the journal
Biological Reviews and carried out by an international team of 39 researchers affiliated with scientific institutions in 11 countries, synthesises more than 20 years of advances in carrion ecology. The authors examine what science gains by incorporating carrion into the way we interpret nature, from individual animal behaviour to ecosystem functioning and human evolution itself.
According to the authors, carrion has traditionally been regarded as a secondary resource consumed only by certain species, such as vultures and hyenas. Recent studies, however, show that it plays a much broader and more profound role.
“Animal carcasses create hotspots of nutrients, organisms and biological interactions that strongly influence the structure and functioning of terrestrial and aquatic ecosystems,” explains Marcos Moleón, a professor in the UGR Department of Zoology and one of the researchers involved in the study.
A new perspective on ecology
Carrion allows some fundamental ideas in ecology to be reinterpreted. For example, the authors show that numerous forms of cooperation and mutual facilitation enable species competing for this resource to coexist.
They also highlight its influence on herbivore populations, its contribution to ecosystem stability and even the links it creates with ecological networks as different as pollination networks, through relationships that extend far beyond who eats whom.
Besides being a nutritious source of food, animal carcasses provide materials for building nests and making tools and ornaments. They also act as hubs of information and communication among members of the same species, while their remains provide structures where numerous species can settle and find shelter.
“We are discovering that many ecological processes cannot be fully understood if the role of carrion is ignored,” explains Eneko Arrondo Floristán, a UGR researcher who co-ordinates the study with Marcos Moleón. “For decades, our study of carnivores focused mainly on their role as predators, but scavenging has far-reaching ecological consequences,” the scientists add.
The implications of carrion extend beyond ecology. In forensic science, a detailed understanding of decomposition processes improves estimates of the post-mortem interval, or the time elapsed since death. In epidemiology, analysing how different species use carcasses helps us understand the role of scavengers in reducing disease spread. In toxicology, certain scavenger species act as excellent sentinels of environmental contamination.
A dietary perspective on human evolution
Carrion ecology offers new tools for interpreting archaeological sites and the fossil record, understanding animal evolution and reassessing certain hypotheses about meat consumption among early humans.
Beyond being a key behaviour among early hominins, scavenging has been a regular part of human subsistence throughout our history: a highly efficient way of obtaining food that complements hunting and the exploitation of plant resources.
In this regard, Ana Mateos notes that “from our origins, humans have been anatomically, physiologically, behaviourally and technologically adapted to be efficient scavengers. The great advantage of scavenging is that obtaining food requires far less effort than hunting.”
Jesús Rodríguez adds that “we now know that carrion is more predictable than previously thought and tends to be most readily available precisely at those times of year when alternative foods are scarcer. It would therefore have been a key resource for hominins during periods of famine.”
A paradigm shift
The study’s main conclusion is that carrion should not be regarded as a marginal resource, but as a central component of ecosystems. Scavenging offers new perspectives for analysing social perceptions of carnivores and the benefits that scavengers provided to human ancestors and continue to provide to modern societies.
Studies of this kind also offer new solutions for biodiversity monitoring and conservation. The authors therefore propose that carrion ecology should be formally recognised as a distinct ecological discipline and present a conceptual framework that integrates its multiple ecological functions and connections with other disciplines.
“The most important point is not simply that we now know far more about carrion than we did 20 years ago,” the authors state. “What truly matters is that we are beginning to understand the extent to which incorporating carrion transforms our view of the natural world and can help answer fundamental questions that have so far remained only partially explained.”
Far from being a mere biological curiosity, carrion is thus emerging as a key element for improving our understanding of nature and connecting disciplines that have long advanced along separate paths.