Biotope principles of sympatry and interspecies hybridization in mammals (by the example of the genus <Emphasis Type="Italic">Spermophilus</Emphasis>)

Two hybridization zones were taken as an example (the russet ground squirrel (Spermophilus major) and the speckled ground squirrel (S. suslicus), the russet ground squirrel and the yellow ground squirrel S. fulvus) to show that biotope characteristics determine segregation of sympatric species in contact colonies. The heterogeneity of biotopes with regard to the requirements of sympatric species promotes their long-term and steady dispersal and, in rare cases, sporadic hybridization. A biotope with a homogenous environment enables wide interspecies hybridization and a rapid increase in the ratio of hybrids in the colony.