Canis familiaris × Ursus arctos
This cross is often listed in older works. Writing during the Elizabethan era, the French humanist writer Pierre Boaistuau, in his Histoires prodigieuses, says dogs and bears were intentionally mated in captivity in London and that sometimes a hybrid resulted. He includes an artist’s illustration of the alleged hybrid (shown at right). These bears and dogs, usually mastiffs, were kept to fight in the bear baitings so popular at the time and a favorite pastime of the Queen. An English translation of the passage in question (Boaistuau 1591, pp. 206-209) reads as follows:
This monstrous animal, which you see illustrated at the beginning of this chapter, was engendered by an English bitch covered by a male bear. As a result, it partakes of the nature of both, which doesn’t seem strange to those who have observed how in London dogs and bears are kept in small cages near each other. Their keepers cage a female bear and a male dog together when they are in heat, so that pressed by their natural urges, they convert their cruelty into love. From such conjunctions are sometimes born animals like this one, although it may be quite rarely. Among these I have seen two, which were given to his grace the Marquis de Trans. One of these he gave to my lord the Conte d’Alphestan, the Emperor’s ambassador. The other, he had taken to France, which I have had reproduced here. The illustrator has omitted nothing. Translated by E. M. McCarthy. Original French: "Cest animal monstrueux, que tu vois figuré au commencement de ce chapitre, est engendré d’un Dogue d’Angleterre et d’un Ours: de sorte qu’il participe de l’une et de l’autre nature: Ce qui ne semblera estange à ceux qui ont observé à Londres comme les Dogues et les Ours sont logez en de petits cachots, les uns aupres des autres: et quand ils sont en leurs chaleurs, ceux qui sont deputez pour les gouverner, enferment une Ourse et un Dogue ensemble, de sorte que pressez de leurs fureurs naturelles, ils convertissent leur cruauté en amour, et de telles conjonctions nayssent quelquefois des animaux semblables à cestuy, encore que soit bien rarement: entre lesquels i’en ay observé deux, qu’on avoit donné à monseigneur le marquis de Trans: l’un desquels il fist present à monsieur le Conte d’Alphestan, ambassadeur de l’Empereur: l’autre qu’il a faict amener en France, sur lequel i’ay fait retirer cestuy au naturel, sans que le peintre y ait rien obmis."
Boaistuau then turns to a discussion of other types of hybrids, but eventually returns to his description of the bear-dog:
But to return to the description of our animal, of which you can see the appearance is so monstrous, which resembles a small bear, and which is also in its movements, its voice, and manner of doing all things more like a bear than a dog. However, I can assure you that he is one of the most ferocious beasts that you will ever see, for there is no species of animal that he will not attack, be it a bear, a lion, or a bull, or others of a similar kind. And he is so ardent in these combats that once he has sunk his teeth into some beast, he would rather be dismembered than relinquish his grip, as I can attest after witnessing him in combat in London against the bear. Translated by E. M. McCarthy. Original French: "Mais afin de retourner à la description de nostre animal, duquel tu vois la figure si monstrueuse, qui ressemble a un ours racoursy, aussi avoit les gestes, le muglement, & toutes ses autres facons de faire plus aprochantes de l'ours que du chien, mais je te puis asseurer que c'est l'une des plus furieuses bestes que l'on puisse regarder car il n'y a espece d'animal auquel il ne s'attache, soit Ours, Lyon, Taureau, & autres semblables : & si est si ardent en ses combatz, que depuis qu'il a mis la dent sur quelque beste, il se feroit plustost demembrer que laisser prise, come j'ay veu par experience à Londres quand on le fist combatre contre l'ours." http://tinyurl.com/nmf6s7l
The exact identity of the bears involved in Elizabethan bear baitings is somewhat in doubt. But it does seem that the brown bear (Ursus arctos) is the animal in question. As Henry Reeks (1878) states in a scholarly article on mammals mentioned by Shakespeare, the brown bear (he refers to Ursus arctos and to its synonym Ursus isabellinus) "would probably be the bear with which Shakspeare [sic] would be most familiar. Bear baiting seems to have been a very popular amusement about that period and for many years subsequently."
Though one might suppose that a brown bear would be far too large to mate with a dog, there is a very wide range of geographic variation in the adult size of these animals. Nowak (1999, pp. 685-686) states that while brown bears may weigh as much as 780 kg (1720 lbs) on the southern coast of Alaska, elsewhere they can be far smaller. For example, the average figure he gives for southern Europe is just 70 kg (154 lbs). It does seem, then, that some bears would be within the size range that would allow mating with a large dog.
The gestation periods of a dog and a brown bear differ widely (63 days in the former versus 215 days in the latter). Their chromosome counts, however, are fairly similar (in dogs, 2n=78, in brown bears, 2n=74). This would be an interfamilial cross (Canidae × Ursidae).
Jakob Benjamin Fischer, too, in his Naturgeschichte von Livland (1791, p. 146), mentions a bear-dog hybrid that was supposedly fertile. And he gives the cross in the same direction (female dog/male bear) as does Boaistuau:
One has the example of a bear mixing sexually with a dog. At Riga, a male bear mated with a bitch, which went on to produce offspring. Among these was a remarkable dog. He had a bear’s head and no tail. His voice was a dog’s bark mixed with the growling of a bear. They let this dog mate with a bitch, but no great caution was taken—she probably mated with other dogs—and at her expected time she gave birth to sixteen puppies (an unusual example of canine fertility) of which only six resembled the bear hybrid, with bear’s heads, shaggy coats, and no tails. One sees from this, that it is in fact possible for hybrid beasts to produce offspring. Translated by E. M. McCarthy.
Of course, nowadays dogs and bears are very rarely kept caged together, and there seem to have been no attempts to cross them by artificial means. So it must remain an open question whether the various early reports of this type of hybrid have any basis in fact.
See also: Scherren (1907, pp. 432-433).
By the same author: Handbook of Avian Hybrids of the World, Oxford University Press (2006).
Domestic Dog × Brown Bear - © Macroevolution.net
An account of Elizabethan bull and bear baiting
"There is still another place, built in the form of a theatre, which serves for the baiting of bulls and bears they are fastened behind and then worried by great English bull-dogs but not without great risk to the dogs from the horns of the one and the teeth of the other; and it sometimes happens that they are killed upon the spot, fresh ones are immediately supplied in the places of those that are wounded or tired." (from Travels in England During the Reign of Queen Elizabeth by Paul Hentzner and Sir Robert Naunton)
Domestic Dog × Brown Bear - © Macroevolution.net