What Species Do Rats Belong To?

We still do not know exactly what species rats are. Genetic studies of modern rat populations are largely limited to successive waves of contact after species establishment. However, ancient DNA may be able to answer questions about the origin of rat species and reveal whether they have had any significant genetic continuity over time.

Different species of rats have different characteristics. The word “rat” is a generic term that refers to several rodent families, including mice and rats. The genus Rattus includes 56 species of medium-sized rodents. Most are native to continental Asia, although some have spread internationally in association with humans.

Ancient black rats were found in different parts of the world and in different time periods. The northern samples, however, were clustered together. This was true for all but one medieval sample from Buda Castle, Hungary. In contrast, medieval samples from Althiburos, Tunisia, formed a clade of their own. They were also found to have greater heterozygosity than northern rats.

Before the introduction of brown rats into temperate regions, black rats were common. However, their populations declined over time because of competition with the brown rat.