Earth’s majestic “apex predators” are some of the most prolific hunters in the world. But which ones kill the most?

Our new research, published in Biological Reviews, showed solitary hunters such as bears, tigers and Eurasian lynx have higher individual kill rates than social predators such as wolves and lions. And smaller species, such as cheetahs and pumas, tend to kill relatively more prey because their kills are often stolen by more dominant carnivores.

Such information allows us to better understand how different predators affect their environment. It can also guide hunting quotas and help evaluate how humans affect carnivores.

These apex predators perform vital roles in ecosystems. Yet tragically they are among the world’s most threatened animals. Carnivores frequently come into conflict with humans, particularly over livestock and public safety.

Our approach

Our research was a systematic, world-first literature review into the predatory behavior of large land-based carnivores. In particular, we examined carnivore “kill rates”—the number of prey killed over time. We did this to better understand their foraging and impacts on prey populations and ecosystems.

We examined 196 papers that either quantified large mammal carnivore kill rates, or reported data we could use to calculate the rates ourselves.

We focused on the large land-based carnivores weighing 15 kg or more. We also searched for kill rate studies on four smaller species—coyote, wolverine, fossa (a cat-like predator found in Madagascar) and the Tasmanian Devil—as they’re all considered apex predators in certain regions and ecosystems.

We only found kill rate estimates for 17 (55%) of the 31 carnivore species included in our review. Studies came from 27 countries across five continents.

Carnivores hunt in different ways

We found kill rates differ between carnivores with different social structures and hunting strategies.

Social predators, such as wolves and lions, tend to kill fewer animals per carnivore than solitary hunters such as bears, tigers and Eurasian lynx. For example, on average, gray wolves made a kill every 27 days per wolf, compared with every four days per Eurasian lynx.

Larger wolf packs can bring down large animals such as bison more easily. Similarly, groups of cheetahs can tackle larger prey than solitary cheetahs. This could mean they don’t need to hunt as often.

Working as a team may also reduce losses to scavengers, as groups can better defend their kills through sheer numbers. Or they might be better at scavenging and stealing (“kleptoparasitism”) from others.

Canine predators such as wolves and African wild dogs often rely on high-energy pursuits over long distances. For example, gray wolves can pursue prey for more than 20km. In contrast, cats rely on stealth, using an ambush hunting strategy. This saves energy.

Solitary large carnivores such as tigers, leopards and Eurasian lynx, which mainly hunt hooved mammals, have similar kill rates regardless of body mass. This suggests large land-based carnivores are compelled to hunt prey closer to their own size or larger, to compensate for the energy used in the hunt.

Smaller carnivores such as cheetahs, pumas and African wild dogs often kill more prey than their larger counterparts, but only consume about half of what they kill.

This behavior benefits other species such as lions, bears and wolves and is likely a consequence of having to compensate for the theft and loss of food. Pumas are thought to provide more than 1.5 million kilograms of carrion a day across North and South America.

If you’ve seen the Lion King movie, you’d be forgiven for thinking hyenas largely steal and scavenge their food. But that’s not the case. Lions often steal from hyenas, as well as from other carnivores such as cheetahs and African wild dogs.

Bias in kill rate research

More than half (55%) of all kill rate studies have been conducted in North America. Africa follows with almost a quarter (24%), then Europe (12.5%).

Asia was a long way behind with 7% of all kill rate studies. That’s just 13 studies covering six species. This is despite being the largest continent, home to 17 (55%) of the 31 large carnivore species included in our review.

No reliable kill rate studies have been published from Australia.

A third (33%) of all kill rate studies focused on gray wolves, followed by pumas (20%), lions (12%) and Eurasian lynx (8%). This means we know little about the predatory behavior and roles of other large carnivores.

Gray wolves are considered a threat to livestock and wildlife that humans value. This has prompted significant investment in research to understand their predatory behavior and that of other large North American carnivores.

Such work has subsequently been used to inform appropriate management and conservation of these predators and their prey.

Carnivores bring benefits

Kill rate studies provide more than just a tally of carnivore behavior. They offer deeper insights into the relationships between predators and prey, and their effects on ecosystems.

Large carnivores shape ecosystems by scaring and killing prey, which can change their behavior, distribution and abundance. They also supply food to other species, affecting the flow of nutrients and energy.

In many ways, large carnivores also help people. They can reduce the risk of vehicle collisions, by killing deer that might otherwise wander onto roads. They may limit the spread of disease by preying on sick animals, and control herbivores, aiding livestock producers.

Yet carnivores, including Australia’s dingo, are still widely persecuted. We need to do all we can to maintain their pride of place at the pinnacle of Earth’s ecosystems.

Of course, if you really want to know which species is the biggest killer, it’s humans. We are the dominant predator across Earth.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

In a new publication, the European Reference Genome Atlas (ERGA) announces the success of its pilot project. This initiative assembled a large collaborative network of scientists and institutions across 33 countries to produce high-quality reference genomes of 98 European species—so far. The pilot project has provided valuable lessons and highlighted key challenges, positioning ERGA as a model for decentralized, inclusive and equitable biodiversity genomics initiatives around the world.

Among many of the project’s milestones are the first chromosome-level genome assemblies of species from Greece, one of Europe’s most biodiverse countries. Species such as the Cretan wall lizard (Podarcis cretensis) and Aristotle’s catfish (Silurus aristotelis) were sampled by local scientists in Greece to produce genomes that are now openly available for anyone across the world to access and study.

The findings are reported in an article published today in the journal npj Biodiversity.

These are but two examples of what can be achieved by uniting an international community of biodiversity scientists, fostering collaboration between and within countries. The ERGA pilot project emphasized equity and inclusion, with the goal that genomic research and resources are accessible to all, regardless of geographical origin. For many of the participating scientists and countries, the project offered the first opportunity to actively engage in the generation of state-of-the art reference genomic resources for their native biodiversity.

The ERGA pilot project was also successful in building momentum and bringing visibility to the growing importance of biodiversity genomics in Europe and beyond. Genomic data hold immense potential to inform conservation actions for endangered species and unlock discoveries in the fields of human health, bioeconomy, biosecurity and many other applications. For example, the greater argentine (Argentina silus) is among the species sequenced by the project—a commercially important fish species from the northern Atlantic.

This new reference genome will enable scientists to make more accurate assessments of the genetic status of the species’ populations, ultimately guiding management decisions to ensure that fishing practices are responsible and sustainable.

One of the species for which a high-quality reference genome is now also available for the first time is the white-tailed eagle (Haliaeetus albicilla). With this reference genome, it will be possible in future, for example, to investigate genetic disorders for which only the symptoms are currently known. This applies in particular to the so-called “pinching-off syndrome,” says bird of prey expert Dr. Oliver Krone from the Leibniz-IZW.

In this disease, the flight and control feathers of young white-tailed eagles are malformed and make flying impossible. The causes of this malformation of the feathers are genetic and are passed on recessively from both parent birds to the offspring. Furthermore, there are many possibilities to utilize the eagle genome for phylogenetic questions, Krone adds. For example, subpopulations could be differentiated from one another or isolated populations could be identified.

As the global scientific community strives to unlock the full potential of genomic data, the establishment of a Europe-wide collaborative network under the ERGA umbrella accelerates scientific progress and facilitates its translation into tangible benefits for biodiversity and society.

Additionally, the network helps scientists at all career stages to find and share opportunities for training, partnerships and funding. The ERGA pilot project was co-initiated in early 2021 by the then ERGA chair Dr. Camila Mazzoni from the Leibniz-IZW and the Berlin Center for Genomics in Biodiversity Research (BeGenDiv) who led calls with hundreds of genome scientists to set up and plan the collaborative project in an inclusive and decentralized way.

ERGA is the European node of the wider Earth BioGenome Project (EBP). In order to achieve its ambitious goal—to sequence all eukaryotic life on Earth—the EBP crucially needs worldwide participation and new, decentralized models of genome production.

The ERGA pilot project was able to show that a fully distributed, collaborative and coordinated genome production model is not only feasible but effective—even at a continental scale and without a central source of funding available. In fact, most of the project budget came from grassroots efforts by individual members and partnering institutions, with additional support from sequencing partners and commercial sequencing companies providing grants, discounts and in-kind contributions.

The ERGA pilot project helped to identify and address the many challenges of working at the international scale. These challenges include dealing with the legal and logistical hurdles of shipping biological samples across borders, resource disparities between countries and the search for balance between decentralization and the need for standardization to guarantee that only the highest possible reference genome assemblies which meet EBP metrics were produced by the project.

ERGA’s decentralized approach holds great promise for the future of biodiversity genomics. The pilot project’s success in building momentum and uniting researchers illustrates the power of this model.

By fostering international collaboration and focusing on inclusivity and equity, ERGA is setting new standards for biodiversity genomics. The lessons learned and the challenges identified and addressed in the pilot project will guide future efforts, promoting robust and standardized workflows and a comprehensive genomic database for species in Europe and beyond.

“The ERGA pilot demonstrated the importance of a well-connected scientific community that is willing to cooperate to achieve a major common goal. This success marks a significant milestone for ERGA, illustrating that such an initiative can be highly inclusive while still maintaining the high standards set by the Earth BioGenome Project (EBP) for reference genome production. This ERGA pilot project provides both an example and a roadmap for distributed efforts to build biogenomes across Europe and potentially beyond,” said Camila Mazzoni, former ERGA Chair and senior author of the article published—team leader “Evolutionary and conservation genomics” in the Leibniz-IZW Department of Evolutionary Genetics.

“The ERGA pilot project attempted to up-scale the generation of high-quality reference genomes across an entire continent. An endeavor of such magnitude was made possible only through its commitment to the principles of inclusion, equity and collaboration as well as the dedication of its diverse, transdisciplinary and cross-sectoral participants. I feel incredibly lucky to have worked alongside such an amazing group of colleagues to help kickstart the construction of a genomics encyclopedia of European species,” said Ann McCartney, Member of the ERGA Pilot Committee—Assistant Researcher at University of California Santa Cruz, and adjunct Assistant Professor at University College Dublin.

“When we took on the leadership of this project, we didn’t anticipate the extent of the work ahead. It was a challenging endeavor, but through perseverance and teamwork, we succeeded. We also had the invaluable support of sequencing centers, universities, and commercial companies who contributed to the ERGA pilot project, offering human resources for library creation, free sequencing and in-kind products. This experience was truly one of a kind,” said Alice Mouton, Member of the ERGA Pilot Committee—former FNRS postdoctoral researcher, and scientific collaborator at the University of Liège.

“ERGA was all a dream, until it wasn’t. Through this pilot project the prospect of uniting Europe under the flag of biodiversity genomics is now reality. We can be proud to have first established the process by which the genomes of many species will become available to the scientific community for conservation and beyond,” said Giulio Formenti, Member of the ERGA Pilot Committee—Research Assistant Professor at the Rockefeller University.

“The ERGA Pilot project is a significant milestone in the Earth BioGenome Project (EBP) and a major step forward for biodiversity genomics in Europe. As the first biodiversity genomics project coordinated at a continental scale, ERGA has demonstrated two fundamental principles on which the EBP was built—the first being that sequencing capacity will be geographically distributed, and the second being that any benefits derived from sequenced genomes would be shared equitably. ERGA is now poised to expand its goals to sequence thousands of genomes for conserving European biodiversity and the growth of a sustainable bioeconomy,” said Harris Lewin, Chair of the EBP Executive Council—Research Professor at ASU.