The Asian house shrew looks like a strange mouse with a long, pointed nose. It smells bad. And, it turns out, it has been悄悄 traveling with humans for thousands of years, carrying secrets in its DNA.
Scientists at Hokkaido University in Japan have discovered that this small, smelly animal is actually a hidden record keeper of human history. By studying the genetic makeup of shrews collected across the Indo-Pacific region, the research team found traces of ancient trade routes and human migrations stretching back roughly 10,000 years.
"Animals that have accompanied humans during their migrations have preserved additional evidence of human activities in their genomes," said Assistant Professor Satoshi Ohdachi, the study's lead author.
The research, published in the Zoological Journal of the Linnean Society, revealed that shrews did not spread across the Indo-Pacific in a single event. Instead, multiple waves of shrews traveled with humans over thousands of years, arriving in different regions at different times. The findings show a far more complex network of human interaction across the Indo-Pacific than historians previously understood.
For example, shrews in southwestern Iran share close genetic links with shrews in Zanzibar, off the coast of East Africa. Meanwhile, shrews on the islands of Mauritius and Réunion are more closely related to Southeast Asian populations, suggesting different groups of people brought shrews from different places. In Japan, shrews on Kyushu Island and the Ryukyu Islands came from different regions, meaning Japan received shrews multiple times from different sources.
The Indo-Pacific is the vast stretch of ocean connecting the Arabian Sea to the South China Sea and beyond. Maritime routes through this region have shaped human civilization for millennia, but much of that history remains mysterious. Ancient trade networks left behind pottery and coins, but they also left behind shrews.
"The movements of these animals mirror the movements of people," Ohdachi noted. \