This is an excellent (and necessary) question - before my Humanities Core class, I had never heard of a bestiary. A bestiary, in essence, is a "book of beasts", much like a dictionary or encyclopedia that specifically focuses on animals (Davis). Bestiaries are compiled from previous sources, and are rich with images, text, Biblical references, and, uniquely, a moral attached to each creature's entry. Bestiaries were popular in 12th century Europe, and can be found in various languages and translations (University of Aberdeen).

The sirens’ claim to fame, above all else, is their voices, and more specifically, how they use it. Sirens are known as lethal seductresses because they would lure sailors towards them with their song: “the sweetness of the sound enchant[ing] their ears and senses and lull[ing] them to sleep” (Barber 150). Once they had successfully sung the sailors to sleep, they would attack the ship and consume its sleeping passengers. Sirens often attacked in groups, some distracting their prey while the others attacked. This representation of sirens leads me to interpret them as a medieval manifestation of humankind’s ‘evil twin’ - the greedy, aggressive, selfish, and murderous reflections of ourselves. The Bestiary analyzes each creature from an anthropocentric perspective, describing each animal as they relate to humans and oftentimes providing a Biblical moral that parallels the behaviour of the animal. According to the Bodleian Bestiary, the myth of the sirens teaches us not to indulge in the vanity and pompous delights in the world, as those who do will “lose the vigour of their minds” and subsequently “become the prey of their enemies,” just as the sailors who fell victim to the siren song did (Barber 151).

What makes the Bestiary more interesting than a typical dictionary is the combination of text, visuals, and morality that comprise it. The Bodleian Bestiary's textual description of the sirens portrays them as "deadly beasts," tricksters who lure "ignorant and imprudent men to their deaths" (Barber 150). Had I read only the text, I likely would have pictured a violent, graphic attack where mermaids kill sailors in a bloody battle. However, the picture in the Bodleian Bestiary contradicts this representation. In the image, the sirens do not appear violent or angry, and the sailors look rather peaceful - one of them even has a slight smile on his face as he's lulled to sleep. This contrast between text and art struck me when I first noticed it, but the more I considered it, the scarier the image became. Deadly as the sirens may be, it's clear they do not appear that way. They're relaxing, soothing, seductive - violent only once their prey is fast asleep. What the illustration from the Bestiary does not show is the attack itself, which may look significantly different than the moments preceding it.