Ever tried to catch a beaver? You may have been surprised when the little critter stopped, cast you a withering look before gnawing its testicles off, offering them up like a bizarre trophy. If you were alive in the times of Ancient Rome, you may well have gobbled up this loopy tale, hook, line and beaver-bollock.  

We know of it thanks to Roman writers such as Pliny the Elder, a wealthy statesman and senator from the 1^st century AD. Pliny scrawled in his Natural History: “The beavers of Pontus cut off these same parts (their testicles) when danger presses, knowing that this is why they are hunted.” 

A century later, the writer Aelian praised the beaver’s actions as those of “a wise man falling among pirates who abandons all that he carries with him for the sake of his own safety.” Ridiculous as this sounds, the Romans had a thing with sacrificial animals; legend had it that elephants would do the same, knocking off their prized tusks instead of succumbing to the hunter’s bow or spear. 

“The beavers of Pontus cut off these same parts [their testicles] when danger presses, knowing that this is why they are hunted.” 

PLINY THE ElDER, natural histories

It is perhaps easy for us to mock the Ancients. But by the time Pliny took to writing his epic compendium on all thing’s natural, beavers had become sparse throughout Italy. Probably due to their popularity in medicine and as a perfume. It is more than likely he never actually saw one in the wild. So too Aelian was repeating stories he had read or heard. The Romans were not the only peddlers of this particular myth. In Ancient Egypt, beavers’ too were said to trim their own testicles. There, however, it was used it as a warning to would-be adulterous husbands.   

So, why were the Romans interested in the beaver’s testicles in the first place? The answer starts with an ancient misconception. 

Castoreum: A source of wealth and health 

The testicles of the Eurasian beaver (Castor fiber) played an important part in Roman, and ancient, culture. Or at least that’s what they thought. This creature’s loins were believed to be the source of castoreum. (Castor is the Latin word for beaver). This musky, vanilla-scented substance formed an integral element in ancient medicine and was also used as a perfume.  

There were few things more effective as a medical cure than beaver testicles in Pliny’s day. In fact, the Romans borrowed this fad from the Greeks. The Hippocratic Corpus, dating from around the 4^th century BC, and based on the teachings of the renowned Greek physician Hippocrates, cites beaver testicles for a number of ailments.  

Beaver testicles were against nervous disorders, scorpion stings and toothaches. They also appeared in ancient painkillers and mouthwash. These ‘pills’ included tears of the poppy, galbandum (a resin from a plant found in Iran), myrrh, castoreum and a touch of pepper. Roman women, meanwhile, burned the stuff and inhaled the resulting fumes. They believed it would induce an abortion.  

As we might rank a fine coffee from Colombia, or a wine from France, the Romans judged the source of their castoreum. Pontus and Galatia, both in modern day Turkey, laid claim to the best. African beavers gave up the second best. For some medical practices, if beaver testicles were not to be found, dried otters’ kidneys were considered an acceptable replacement. 

The ancient physicians weren’t too far off the mark either; castoreum contains salicylic acid, aspirin’s active ingredient, and helps us fight a range of bodily issues like warts and dandruff. The difference is that we know exactly where it comes from: It’s a secretion from the beaver’s anal gland and is used by the little critters to mark their territory in the wild; part of a compensation package granted by nature to make up for their poor sight and hearing. So, those self-castrating beavers in Pliny and Aelian’s stories were clearly pulling a fast one on their pursuers.   

As all good, however unbelievable, stories do, the self-castrating beaver tale took an age to die out. It was still floating around in medieval times and was adopted by the Church. Artistic monks moulded the beaver’s plight into a lesson on morality and chastity, illuminated forever in medieval bestiaries. It was not until the 17^th century that the myth was well and truly busted. Sir Thomas Browne, an English naturalist and polymath, pointed out the beaver’s attempts to “Eunuchate or castrate” himself was in fact impossible on account of its testicles being found inside its body.  

Sir Thomas Browne laid the origins of the myth at the feet of the Egyptians. Hieroglyphics have been found relating a tale of beavers that were said to trim their own testicles. It was used it as a warning to would-be adulterous husbands. From there, “by process of tradition, stole into a total verity,” among the Greeks and the Romans.   

That a Bever to escape the Hunter, bites off his testicles or stones, is a Tenet very ancient; and hath had thereby advantage of propagation.

sir thomas brown, of the bever

But castoreum continued to be praised for its medicinal powers. Nicholas Culpeper, an English physician in the 17^th century, wrote, in what could be considered an ode to the healing powers of castoreum: “[It] resists poyson, the bitings of venemous beasts, it provokes the terms and brings forth birth and after birth, it expels wind, easeth pains and aches, convulsions, sighings, lethargies, the smell of it allaies the fits of the mother; inwardly given, it helps tremblings, falling sickness, and other ill effects of the brain and nerves.” 

So, lopping off their testicles for hunters to find was nothing but a ruse, albeit a painful one for the species in questions. Across its range the Eurasian beaver has only recently made a comeback. Hunted to the brink for its testicles, fur and meat, the critter was near wiped out across most of its range by the 20^th century. The words of the Roman writer Juvenal seem rather fitting: “Thus, when the cause of your danger has been by yourself removed, oh Pontic beaver, you have a safe hold on whatever’s left.”