Like I said, Dante Alighieri’s time in the Apuan Alps as well as Verona’s proximity to it (especially towards Germany, Austria and Switzerland) would’ve influenced him a lot. If extrapolated from demonology texts like Compendium Maleficarum, De Lamiis Et Pythonicis and Manuale Exorcistarum (or Candido Brognolo’s other works) where they’re published in Northern Italy and Southern Germany respectively as well as Demons of Urban are any indication, mountains attract fear.
Even in Ukraine and parts of Russia, witches are associated with mountains and from what’ve read witches would appear as cats, dogs and pigs when entering black sabbaths on Bald Mountain. (Though it could also be that some people have acrophobia as well as weather complicating matters in European mountains.) The former four mention wolves being connected to witchcraft, especially as forms demons take and as witches’ familiars. Another document, Displaying of Supposed Witchcraft, enlists wolves as one of the witches’ favourite guises.
(Various other sources cite werewolves being able to appear as cats and dogs.)
There’s no doubt Dante would eventually get used to it. But I also wouldn’t doubt if at least with Compendium Maleficarum mentioning demons appearing as cats and dogs (also agreed in Henri Boguet’s Discours des Sorciers and Francois Perrault’s Demonologie) as well as leopards and wolves suggests such beliefs would’ve already existed in Dante’s time.
They just have to wait longer to get recorded.