The frontispiece of his work states "Forma & Natura & Costumi de lo Rinocerothe stato condutto importogallo dal Capitanio de larmata del Re & altre belle cose condutte dalle insule nouamente trouate"" (English: The Shape, the Nature and the Way of the Rhinoceros brought by the Captain of the Portuguese King's Armada and other beautiful things brought from the new insulars).
There is only an identified surviving copy of this work and it is held at the Bibliotheca Colombina in Seville, Spain, under the library code signatura: 6.3.29(32)).
Apparently he had purchased the book and, on the bottom of the last page of the text, he took note of the date and the place of his acquisition: "Este libro costó en Roma medio quatrain por nouiembre de 1515 / Esta registrado 2260" followed by his signature.
His lack of poetic talent was mentioned by Penni, himself in the XXI verse (at left the original text and at the right the English translation): One can also notice that the poem was published only two months after the arrival of the rhinoceros at Lisbon.
These three factors may lead some investigators to conclude that Penni somehow copied the work regarding the Elephant pamphlet, by an unknown artist, and adjusted it to the rumours, not all correct, that were spreading in Rome regarding the Portuguese "Ganda".