How do you say tortoise in Japanese?

かめ (kame) (kah-meh) is "turtle" in Japanese, but the correct Word for "tortoise" is リクガメ　(Rikugame) (Ree-koo-gah-meh) - notice that the Word (kame) is still present, but the k has now changed to a g sound.

The kanji for the Word turtle is 亀　but the Word for tortoise is usually written in katakana as tortoises are not native to Japan.