Between 50,000 and 10,000 years ago, Earth lost many of its giant animals that once dominated ecosystems across continents.
Saber-toothed cats hunted with long, curved fangs. Massive ground sloths grew as large as elephants. Woolly mammoths roamed cold regions, with tusks stretching more than 12 feet. In Australia, wombat-like giants weighed up to three tons.
For millions of years, these animals shaped landscapes and food chains. Then, in a relatively short period, most large mammals—especially those weighing over one ton—disappeared. Researchers describe this as a major extinction event.
Study finds lasting changes in food webs
A new study shows that the loss did more than reduce biodiversity. It reshaped entire food webs, altering how species interact. The effects are still visible today. The findings were published in Proceedings of the National Academy of Sciences.
Food webs describe who eats whom in an ecosystem. When large species vanish, these networks can shift quickly. Predators lose key prey. Herbivores that once shaped vegetation have disappeared. These changes can weaken ecosystems and reduce their stability.
Researchers analyze global predator-prey data
To examine these patterns, a team led by Lydia Beaudrot and first author Chia Hsieh analyzed predator-prey data from 389 sites across tropical and subtropical regions in the Americas, Africa, and Asia.
The dataset included more than 440 mammal species, from large carnivores to herbivores. By combining data across regions, researchers built a clearer picture of how modern food webs function.
Americas show the strongest impact from past losses
The results reveal big regional differences. Food webs in the Americas contain fewer and smaller prey species than those in Africa and Asia. Predators in the Americas also rely on a narrower range of prey, with less overlap in hunting patterns.
The extinction of giant animals 10,000 years ago is still shaping ecosystems today.
A new study shows that losing megafauna didn’t just reduce biodiversity. It changed entire food webs. The impact is strongest in the Americas, where ecosystems became less flexible. pic.twitter.com/6mfjnNQmfj
— Tom Marvolo Riddle (@tom_riddle2025) April 28, 2026
Researchers link these patterns to earlier extinctions. The Americas lost more large mammals than other regions. Over the last 50,000 years, more than three-quarters of mammals weighing over 100 pounds disappeared there.
Loss of prey reshaped ecosystems
In South America, large herbivores such as giant deer once supported predators like saber-toothed cats and dire wolves. When these prey species vanished, food webs became thinner and less connected.
Researchers say much of the lower part of the food web was lost. This reduced the flow of energy through ecosystems and limited the stability of predator-prey relationships.
Causes of extinction are still debated
Scientists continue to debate why these animals disappeared. Some point to climate change at the end of the last Ice Age. Others highlight the spread of early humans and increased hunting pressure.
Despite the uncertainty, researchers agree on one point. The disappearance of these animals left long-term marks on ecosystems.
Findings offer a warning for today’s species
The study also highlights risks facing modern wildlife. Nearly half of all mammals weighing more than 20 pounds are now listed as vulnerable, endangered, or critically endangered by the International Union for the Conservation of Nature.
Researchers say further losses could trigger similar disruptions in ecosystems. Beaudrot said the next step is to examine whether past extinctions have made some regions more vulnerable today. Hsieh added that studying these patterns can help scientists better predict future changes.
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