It is an interesting discussion.
English is my third language and I never met the word "tortoise " in any workbooks. It was always "turtle". In Spanish "tortuga" is for turtles and tortoises.
When I took my tortoise to roam in a front yard my neighbors' kids called him "turtle ", so I...
I love all tortoises but "Russians" are my weakness. I had a Russian boy for 18 years in Siberia (not the hottest place in the world) and now I have another Russian in Texas.