Commentary Inf VI 28-32
This is the only simile found in this, the shortest canto we have yet read (only Inferno XI will have so few verses -- 115). The distribution of canto lengths throughout the poem would seem to indicate that Dante originally was limiting himself to composing in shorter units than he would generally employ later in his text. If we examine the first twenty cantos we find that fourteen, or 70% of them, are 136 lines long or fewer (115 to 136), while 9 (or 11%) of the final eighty are in this group (and all of these between 130 and 136 lines). Confining ourselves to the very shortest cantos (those from 115 to 130 verses), we find that these occur six times in the first twenty cantos, with only one (of 130 lines) in this shorter group occurring after Inferno XX. Of the eighty final cantos, 88.75% (71 of them) are between 139 and 160 lines long; only 11.25% (9 cantos) of the final eighty are 136 lines or fewer. See Ferrante (Ferr.1993.1), pp. 154-55, for the distribution of Dante's canto lengths. Such data surely make it seem that Dante was experimenting with this distribution as he progressed, a tentative conclusion that would cast some doubt on the position of Thomas Hart, who has argued, carefully and well, that it seems plausible that Dante may have planned even these details from the very beginning. For a summary of his copious and interesting work, affording an overview of it, see Hart.1995.1.

It is as though Dante had begun paring his art, striving for succinctness more than he had before. Up to now, we have found similes an important structuring device in the first two cantos (see discussion at C.Inf.II.127-130), in the third canto (C.Inf.III.112-120), and in the fifth ([Inf V 40-49]; [Inf V 82-85]). Only the fourth, given over nearly entirely to conversation about the nature of the Limbus and to a catalogue of the forty souls identified as being there, is without a simile (although it does contain a dramatic simple comparison [[Inf IV 96]]).

Mirroring the low-mimetic tone of this canto, this its only simile for the first time turns to what we might refer to as 'scenes from daily life,' those wonderfully realistic touches that reveal what an intense and skilled observer Dante was of such scenes. Many later similes in Inferno will also reveal this trait.

Boccaccio (DDP Boccaccio.Inf.VI.7-12) sees the bellowing of Cerberus (v. 32) as antithetic to the music played at banquets, the setting in the world above for the gluttony that is punished here. Padoan (DDP Padoan.Inf.VI.32) points out that this description of the effect on the guilty souls of Cerberus's barking mirrors the verse in Virgil describing a similar effect: Aen. VI.400-1: 'licet ingens ianitor antro / aeternum latrans exsanguis terreat umbras' (if, from his cave, the huge gatekeeper may indeed terrify the bloodless shades with his endless howling).