Doubling Up Biological Names

Rattus rattus (black rat) is coming to a town near you, while Gallus gallus (wild chicken) has got scientists all in a flap (you’ll find out why later this week). Then there’s Bubo bubo (the eagle owl)…and many others.

Can any biologist Sciencebase reader explain to me why there are so many species where the scientific binomial (commonly referred to as the “Latin” name) is like this, the first and second part being the same? I’m sure I’ve missed something obvious, but surely it’s not simply a lack of imagination.