How giants that vanished 10,000 years ago triggered ripple effects that are still felt today

Key Points:

• Between 50,000 and 10,000 years ago, many of the world's largest mammals, especially those over a ton, went extinct, profoundly altering food webs for surviving species, with the Americas experiencing the most severe impacts.
• A new study analyzing predator-prey relationships at 389 sites across the Americas, Africa, and Asia found that food webs in the Americas today have fewer and smaller prey species, with predators showing narrower prey preferences compared to other regions.
• The severity of prehistoric extinctions, particularly the loss of over three-quarters of mammals over 100 pounds in the Americas, played a crucial role in shaping current food web structures, more so than present-day environmental factors.
• The causes of these ancient extinctions remain debated, with hypotheses including climate change and human expansion, but the study confirms these losses have had lasting ecological consequences.
• Understanding these past extinctions provides valuable insights for current conservation efforts, as nearly half of mammals over 20 pounds today are at risk, and researchers aim to assess how historical losses may affect ecosystem vulnerability in the future.