Brown Rat Sea Voyage

The dominance of brown rats all over North America, particularly in the eastern region, is a tale of ecological competition and mysterious conquests. The brown rats, with their aggressive nature and larger size than black rats, swiftly established dominance over their rat counterparts in Europe, eventually spreading across the Atlantic on ships and claiming territory in the Americas.

To unravel the narrative of rat conquest in North America, researchers led by Eric Guiry conducted molecular analyses on rat bone samples from archaeological sites dating back to the 1550s. This study, published in Science Advances, shed light on the fundamental differences between the two species and provided insights into how brown rats supplanted black rats. By innovatively utilizing shipwrecked rat samples, the researchers were able to pinpoint the arrival of brown rats earlier than previously thought, challenging historical records.

The research also delved into the dietary habits of brown and black rats over the centuries, revealing differences that suggested they occupied distinct ecological niches. Despite this divergence, the brown rat's dominance remained a puzzle. While theories point to their aggressive nature and size advantage, there are regions where black rats thrive instead. Further studies, perhaps focused on a single city, could offer deeper insights into the mechanisms behind this transition. Guiry's ongoing work in Europe and the abundance of rat bones worldwide promise further revelations in the understanding of rat colonization and conquest.