This early fictional monster, Beowulf’s challenge in Heorot, is a monster drawn not from Nature, but from imagination. It is, of course, strong, ferocious, a carnivore, but a water-dweller (he lives with his mother in a pool nearby). We can assign it claws and teeth and limbs (since Beowulf tears its arm off). The important feature of Grendel often overlooked in citing Beowulf’s heroism is that this is Grendel’s home territory, its hunting ground, and the humans are the intruders, so Grendel is acting on its survival instincts when he hunts the warriors (and he apparently is a nocturnal hunter). It is important to remember that it is a fictive device, a “personification” of destructive elements in a foreign land, and not part of any natural taxonomy or “chain of being.” And it is clearly wrongheaded to try to equate Grendel with a real animal, like a bear or tiger.