Over the past thousand years, the world has seen an unusual trend: domesticated animals are becoming larger, while wild animals are becoming smaller. A new study from France has found that human activity is the cause of these opposing changes.
Archaeologist Cyprien Mureau and his team analyzed more than 81,000 measurements of animal remains from 311 archaeological sites. The results showed that animals such as chickens and cattle increased in size over time, while wild species including foxes and deer decreased in size.
According to the researchers, the expansion of human settlements is leading to the reduction and fragmentation of wildlife. Less available resources and more intensive hunting are forcing wild animals to become smaller and smaller in number.
At the same time, humans have been deliberately breeding larger domestic animals to get more benefits from them. “A larger sheep produces more wool, a heavier cow produces more meat, and a larger chicken produces more eggs,” the scientists explain. Today, domesticated chickens have a biomass three times greater than all wild birds combined.
The study also found that this process is not limited to land animals. Some bird species, such as puffins and swallows, are becoming smaller. In addition, overfishing has caused many species to shrink by 20%.
These results highlight the significant impact human activity has on ecosystems around the world. Scientists note that our actions, often without considering the long-term consequences, can irreversibly change nature.
