Beavers are so misunderstood. Common fiction draws them as happy tea drinking critters who build lodges among serine banks and woods and rolling meadows. In reality, they are cat sized water rats who leave no tree standing or a daisy blossoming above the water within 20-30 meters of their lodge. I know that because they are gnawing on my woods and they are flooding my meadows.
Beavers have been misunderstood for a while. In middle ages they were pictured dog-size or larger. Beaver testicles were believed to have had medicinal properties; as a result, they were heavily hunted. Manuscripts often feature a hunting scene from the fable, first recorded by Aesop in the 6th century, where
beaver, a four-footed animal that lives in pools, knows that he is hunted for his testicles, which are used to cure ailments. When pursued, the beaver runs for some distance, but when he sees he cannot escape, he will bite off his own testicles and throw them to the hunter, and thus escape death (...)
|Hunting beaver. Bibliothèque Nationale de France, BNF Fr 9136
|Hunting beaver. France; c. 1450. (The Hague, MMW, 10 B 25)
|Beaver biting off his testicles. Bestiary and Lapidary ('the Rochester Bestiary')
c 1230-14th century (British Library)
|Beaver biting off his testicles. Koninklijke Bibliotheek, KB, KA 16, Folio 49v
|One beaver biting off his testicles while the other one is showing the lack of them. British Library, Harley MS 4751, Folio 9r
|Beaver biting off his testicles. Bodleian Library, MS. Canon. Ital. 38, Folio 61r
|Beaver throwing testicles at the hunter. Kongelige Bibliotek, Gl. kgl. S. 3466 8º, Folio 32v
|Beaver throwing testicles at the hunter. Kongelige Bibliotek, Gl. kgl. S. 1633 4º, Folio 8v
A beaver, having previously bitten off its testicles to foil a hunter, shows another hunter that it has nothing he wants. British Library, Royal MS 2 B. vii, Folio 102r
I could not find much information on the use of dog-like and beaver-like images, but it seems that dog-image dominated the hunting scenes in relation to the fable, while beavers remained beavers elsewhere. Here is an image of beaver in marginalia.
Here are two later images of beavers from the 16th and 17th centuries.
|page 336 of Konrad Gesner's Historiae Animalium, Volume I, 1551
|The History of Four-Footed Beasts and Serpents, published in 1658 (Edward Topsell)
Beavers are also found surprisingly extensively in heraldic emblazons from the Middles Ages, with both dog-like and the beaver-like images used. A good compilation of various emblems can be found at Heraldic Beavers in period and in the S.C.A.
In January, 2004, the S.C.A. sovereigns of arms wrote:
The heraldic beaver is drawn with a stocky, smooth-furred. . .body, a wide (usually, but not always, paddle-like) tail, and small or nonexistent ears. It is sometimes contorted into an unspeakable posture based on the medieval view of this animal's habits. . .Some heraldic beavers did not resemble naturalistic beavers .
|BSB Cod.icon. 307, page 152
|BSB Cod.icon. 312 c, page 114
|BSB Cgm. 7249, image 298
Contemporary depictions of beaver are abundant in children's literature. Beaver stands in line with Mr. Ratty and Mr. Toad as a cute pet of the English ponds from the innocent times passe.
However - on July 18th 2013 the first wild beaver living in England for more than 500 (Telegraph) or 800 (Independent) years is believed to have been spotted by a woman walking her dogs in Devon. With good wildlife conservation, beavers should not take long to establish themselves (they are doing very well without any conservation efforts out here).
In ten years or so, the few English trees that have been spared by the industrial revolution will be reduced to sharpened stumps.
PS A well illustrated website on Medieval Bestiary: http://bestiary.ca/index.html
PPS Beaver castoreum (glands) dried can still be bought for $200 per kg.