What genetic reality supports classifying Zebu and European cattle as subspecies?
They can successfully interbreed and produce fertile offspring
The primary biological justification for grouping Zebu (*B. taurus indicus*) and European cattle (*B. taurus taurus*) under the single species designation *Bos taurus* is their proven ability to produce viable, fertile hybrids when they interbreed. In taxonomy, the capacity for fertile cross-mating is a strong indicator that two populations belong to the same species, even if they have significant geographic separation, morphological differences, and distinct domestication histories. This interfertility weighs heavily against arguments for treating them as completely separate biological species, favoring the subspecies relationship which acknowledges distinct ancestral lineages while confirming shared specific ancestry.
