This article demonstrates how one of the features of the Persian script in the past has challenged the reading of certain passages in manuscript versions and has caused misreadings. This feature is the similarity between the letters 'ک' and 'گ', which have been written quite similarly at times without any distinguishing mark, making the written form of certain words that differ only in these two letters uniform. Our focus is particularly on the names of two animals, 'کرگ' (rhinoceros) and 'گرگ' (wolf), which have been used in the poetry of Qaṭrān Tabrīzī, a 12th-century poet. We are aware of the characteristics of these two animals from ancient texts related to animals as well as literary works that have reflected this zoological knowledge. However, the editors of Qaṭrān’s recently published Dīvān have made mistakes in identifying these two animals in certain instances. Here, by drawing on some zoological knowledge and certain collocations in the Persian and Arabic textual traditions and post-Islamic Pahlavi literature, we have proposed evidence for the correct reading of the word.