(Medieval) Fantastic Beasts and Where to Find Them: Imagining Animals in the Middle Ages

medieval fantastic beasts

By Minjie Su

The wild landscape in the medieval imagination is both enchanting and enchanted. The world is largely unknown, and nature is both feared and revered. The fleeting shadows in the deepest woods may be dangerous, deadly, but they may also be wonderful and fantastic. In the fashion of Hogwarts textbooks, here we list some imagined (or not?) creatures that roam and roar in this land of wonder.


We start with the smallest, but by no means the least significant or the least deadly. The name of formicoleon is two Latin words meshed together: formico– from formicare, ‘to creep like an ant’, and, leon, ‘lion’. But it is not a creeping lion; rather, it is an ant-lion, a very tiny ‘worm’ that is extremely dangerous to ants.

Formicoleon, also known as a Myrmecoleon, from the Hortus Sanitatis of Jacob Meydenbach, 1491

In Isidore of Seville’s Etymologies, an etymological encyclopaedia composed in the 7th century, formicoleon is said to have been named so because it is an ant and a lion at the same time: to the ants, it is a lion, for it devours ants as lion devours other animals; but to the other animals, it is an ant, for it is so small that anything larger than an ant can easily trample it to death. According to Vincent of Beauvais, who wrote Speculum Maius (The Great Mirror, 13th century), the nature of the formicoleon has its root in the worm’s ambiguous position between insects and beasts. That is to say, it is too big for an ant, but too small to be counted as a beast. When it is small and weak, Vincent tells us, it is meek and mild, and quite harmless even to the ants. But once it has grown bigger, it begins to feel contempt towards its former kinds, but longs to join the larger. Although there is no way that it can be accepted as a lion, it acts like one and falls upon the ants, killing them and stealing their food for winter.


The bonnacon is first recorded by Pliny the Elder, the Roman commander and historian who died in the fire of Pompeii in 79 AD. In his Historia Naturalis, he describes an animal called bonasus. It is a wild beast found in Paeonia and ‘has the mane of a horse but in all other respects resembles a bull’. The horns of the bonnacon are curved backwards, so they cannot be of any use in fighting – when confronted, the bonnacon just has to run away. However, this does not mean it is fair game. While running, the bonnacon will emit a long trail of scorching dung to keep the pursuers at safe distance.

A bonnacon, from a medieval manuscript. Kongelige Bibliotek, Gl. kgl. S. 1633 4º, Folio 10r

In the Aberdeen Bestiary (MS 24, dated to the 12th century), the bonnacon is relocated to Asia. The horns are still as coiled and useless as in Roman imagination, but the dung develops from very hot to actually flammable: it sets the pursuers on fire, should they be stupid enough to touch it.



Another beast with horns that are not so useful in fighting is the ibex. According to Pliny the Elder, the ibex is basically a kind of wild goat but with enormous horns that are rather disproportionate to its body. The horns are exceedingly strong that, if the beast falls from a high place, the horns will support the body and save it from harm. They also help the beast with running: whenever there is a need, the ibex will swing itself towards the horns and be hurled as if with a catapult.

Ibex show in British Librry MS Harley 4751 f. 10

As time passes on, the ibex’s love of high place becomes so distinguished that Isidore of Seville believes the word ibex comes from avex, because it loves height as a bird (avis) and, therefore, is barely (vix) seen.

Later, in the Aberdeen Bestiary, the ibex becomes imbued with religious and symbolic meanings. The two horns are likened to the two Testaments, with which the learned men can support themselves; however great the fall, they can always bounce back with faith and knowledge as an ibex with its horns.


Barnacle Goose

In his ‘travel’ journals, Sir John Mandeville mentions a marvellous plant he encounters in a kingdom called Caldilhe in Upper India. When you cut open the fruit when it is ripe, you will find ‘a little beast of flesh, bone, and blood, like a little lamb without wool’. Both the fruit and the beast are edible – in fact, Sir John himself has tried it and thinks it is wonderfully delicious. This reminds him of a similar marvel native to his land: the barnacle goose, a kind of bird that is born from trees.

Barncle Geese from British Library MS Royal 13 B VIII f. 8v

According to the Bodleian bestiary (MS. Bodley 764, Oxford), the Barnacles are the native of Ireland. They are products of nature that ‘contradict her own laws’, for, although they are essentially a smaller version of geese, they grow on pine-logs that float on the water. Like that they hang there by their beaks, protected by a shell, until they are fully grown. Then they fall or fly away. It is believed that, in certain parts of Ireland, men of religion eat barnacle geese on fasting days, because it will not be considered as a sin, for these birds are not born of flesh.

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Top Image: Italian fresco of a Formicoleon – Photo by Wolfgang Sauber / Wikimedia Commons




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