The medieval world – largely unknown and full of danger – was difficult for people to understand. The boundaries between the living and the dead were far more blurred than they are today, and all manner of spiritual beings were believed to be locked in constant battle for the souls of the living. Only God and the Church were thought to provide divine protection from such terrors, and it was through both that medieval men and women sought to comprehend, and survive, the world.


In the words of 12th-century philosopher Alan of Lille: “Every creature in the world is a book or a picture or a mirror for us.” For medieval society, God was the book’s author, and the creatures he had created could be explained and understood in terms of their place in the Christian world view.

Perhaps nowhere else is this fascination with the meaning of nature and its relationship to God as evident as in medieval bestiaries. These illustrated compendiums of beasts popular in the Middle Ages, – like bestiaries of ancient times – described the characteristics of all manner of creatures, but also explained them in terms of their place within the Christian world.

The animals that inhabited medieval bestiaries range from the fantastical to the ordinary – although even the most common creatures boast a few ‘unusual’ characteristics, courtesy of our medieval forebears.

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Cynocephali –Dog-headed men

Cynocephali – Dog-headed men (Photo by Getty)
Cynocephali – Dog-headed men (Photo by Getty)

Allegedly possessing the body of a man and the head of a dog, legends and myths of the Cynocephali date back as far as ancient Greece. The 14th-century Muslim scholar and explorer Ibn Battuta even claimed to have encountered Cynocephali on an island between India and Sumatra: “Their men are shaped like ourselves, except that their mouths are shaped like those of dogs.”

Sawfish – Devilish sea monster

Sawfish – Devilish sea monster
Sawfish – Devilish sea monster (Photo by Alamy)

Medieval sawfish were usually depicted with huge wings, which were said to hold wind back from ships’ sails – an aquatic representation of the Devil, who sought to hold back holy inspiration from humankind.

Yale – A flexible fighter

Yale – The flexible fighter
Yale – The flexible fighter (Photo by Bridgeman)

According to Pliny the Elder, writing in the first century, the horse-sized Yale was found in Ethiopia. The Yale boasted long, flexible horns. If fighting, it pointed one of its horns backwards – a reserve weapon to bring to the front should the other be damaged.

Leucrocotta – Imitator of the human voice

Leucrocotta – Imitator of the human voice
Leucrocotta – Imitator of the human voice (Photo by Alamy)

Don’t be fooled by its broad smile. The Leucrocotta – product of the coupling of a hyena and a lioness – was said to be a deadly enemy of both humans and dogs. Believed to hail from India and northern Africa, its mouth stretched from ear to ear, with a single ridge of bone instead of individual teeth. It was said the Leucrocotta could imitate human speech, luring its victims by name into the depths of the forest.

Caladrius – Healer of the sick

Caladrius – Healer of the sick
Caladrius – Healer of the sick (Photo by Alamy)

Described by ancient Greek biographer Plutarch as being “endowed with such a nature and character, that it violently attracts to itself the disease”, in medieval society the Caladrius represented Christ, healing the sick by looking into a patient’s face. But if the bird turned its face away, the patient was doomed.

Parandrus –Master of disguise

Parandrus – Master of disguise
Parandrus – Master of disguise (Photo by Alamy)

Allegedly found in Ethiopia, the Parandrus’s most notable characteristic was that it could change its appearance and conceal itself within its surroundings. Ox-sized and cloven-hoofed, it had a stag’s head with large antlers and long hair.

Hydrus –Sworn enemy of the crocodile

Hydrus – Sworn enemy of the crocodile
Hydrus – Sworn enemy of the crocodile (Photo by Alamy)

A type of serpent, the Hydrus (signifying Christ) was said to roll in mud then creep into the mouth of a sleeping crocodile (a representation of Hell). Once inside, it was believed the Hydrus ate its way out of the crocodile’s stomach, killing it. According to Isidore of Seville, writing in the seventh century AD, the Hydrus lurked in the River Nile.

Siren –Angel-voiced temptresses

Siren – Angel-voiced temptress
Siren – Angel-voiced temptress

Half beautiful woman, half fish or bird, Sirens were believed to lure sailors to their deaths with their sweet singing. Norman cleric Guillaume de Clerc described how: “Entranced by the music, they [sailors] fall asleep in their boat, and are killed by the siren before they can utter a cry.” To the medieval mind, Sirens symbolised the risks of succumbing to worldly temptations.

Basilisk – Serpent-tailed killer

The Basilisk – The serpent-tailed killer
The Basilisk – The serpent-tailed killer (Photo by Bridgeman)

Included in the reptile section of medieval bestiaries – and JK Rowling’s Harry Potter And The Chamber Of Secrets – the Basilisk is often described as the ‘king of creeping things’. Despite being able to kill with its scent, hiss and even its gaze, the fearsome Basilisk could itself be slain by the bite of a humble weasel.

Manticore – Feaster of human flesh

Manticore – Feaster of human flesh
Manticore – Feaster of human flesh (Photo by Bridgeman)

The Manticore, said to be found in India, comprised the body of a lion and the face of a man, rounded off with the stinging tail of a scorpion. The 13th-century scholar Bartholomaeus Anglicus described the Manticore as having a “horrible voice, as the voice of a trumpet, and he runneth full swiftly, and eateth men”.

Bonnacon – Kills with its dung

Bonnacon – Kills with its dung
Bonnacon – Kills with its dung (Photo by Alamy)

Despite its large horns, the Bonnacon was known for another, far more deadly weapon: its fiery dung. Medieval bestiaries describe how, when being pursued, the Bonnacon could expel its dung across an area of up to two acres, burning anything in its path.

Not-so-fantastic beasts

Medieval society also had some curious ideas about some of nature’s more familiar creatures

Barnacle goose

According to medieval bestiaries, barnacle geese grew on trees that overhung water. Once fully grown, the birds were said to fall from the tree. Those that fell on land would die. Those that landed on water floated and survived.


Owls were generally seen in a negative light, living in darkness in the same way, it was thought, as those who had given themselves up to sin. It was believed owls cried out when they sensed someone was about to die.


Beaver testicles were often used in medieval medicine. Hunted beavers were said to bite off their own testicles and fling them at the hunter in order to end the pursuit.


The industriousness of the humble spider was not lost on medieval society, which saw the arachnid as an aerial worm that took its food from the air. It was also believed that if a spider tasted the saliva of a fasting man, it would die.


At harvest time, it was believed hedgehogs climbed grape vines, shook the fruit to the ground, then rolled in them. They would then, it was said, use their spikes to carry the fruit home to their young.

Charlotte Hodgman is editor of BBC History Revealed


This content first appeared in the January 2020 issue of BBC History Revealed