Cat × Rat

Felis catus × Rattus rattus

Hybrids out of History

Video of a cat nursing a baby rat

EUGENE M. MCCARTHY, PHD

     
We find means to make commixtures and copulations of divers kinds, which have produced many new kinds, and them not barren, as the general opinion is.
—Francis Bacon, New Atlantis (1627)
John Locke
John Locke
(1632-1704)

Rattus rattus
Black Rat (Rattus rattus)
Credit: Liftarn (Wikipedia)


Note: It has been my policy in listing reports of mammalian hybrids to include all serious allegations by serious individuals, especially scholars, whether or not the hybrid alleged seems possible or likely to me. This policy, I think, helps to eliminate subjective judgment on my part, and therefore should eliminate at least one source of systematic bias from my work.

John Locke (1632-1704), the English philosopher, is regarded as one of the most influential thinkers of the Enlightenment. Thomas Jefferson, for example, placed him on the highest rung of genius: “Bacon, Locke and Newton... I consider them as the three greatest men that have ever lived, without any exception” (letter to Richard Price Paris, Jan. 8, 1789). Through Jefferson, Locke's ideas shaped the Declaration of Independence.

What are we to think then when an individual with such a forbidding intellect claims to have seen a cat-rat hybrid? In An Essay Concerning Human Understanding (III, Ch. 6, 23), Locke gives the following brief, but eyewitness, report:

I once saw a creature that was the issue of a cat and a rat, and had the plain marks of both about it; wherein nature appeared to have followed the pattern of neither sort alone, but to have jumbled them both together.

If in making this claim Locke was correct, the sire in the cross would almost certainly have been a black rat (Rattus rattus), since at that time the brown rat (Rattus norvegicus) had not as yet reached Britain.

In the next century, the French naturalist Jacques-François Dicquemare (1733-1789) refers to what is probably the same case (Dicquemare 1778, p. 213):

Jacques-François Dicquemare
Jacques-François Dicquemare
(1733-1789)
The female cat covered, in London, by a big rat, gave birth to young, which resembled both cat and rat, and were raised in the menagerie of the English king. Translated by E.M. McCarthy. Original French: “La chatte couvert, à Londres, par un gros rat, donna des petits qui tenoient du chat & du rat, & qu’on élève dans la Ménagerie du Roi d’Angleterre.”

Is such a thing possible? The easy answer is “No.” But an honest one is that we simply know very little about the factors governing the ability of such disparate animals to hybridize. There is enough evidence that cats hybridize with rabbits that many people are convinced, which is a rather similar cross to the one under consideration here.

reality thermometer
Reality Thermometer (estimated reliability of this cross).

So who knows? Perhaps a rat gamete and a cat gamete can on rare occasions combine and sort things out sufficiently to produce a viable organism. But any definite conclusions on this point will have to await firmer evidence. In the meantime, it can only be said that the evidence supporting this cross is meager indeed (as indicated by the reality thermometer at right).

And then there's the question of whether a rat is physically capable of covering a cat. Certainly, it's true that rats and cats raised together get along well, and can even be snuggly friends, as can be seen in various YouTube videos.

Indeed, as surprising as it may seem, it's known that tame cats will on occasion nurse baby rats (as shown in the video at the top of this page), a significant fact in the present context; most mammals (and birds) imprint on the type of animal that raises them, that is, when they reach sexual maturity, they will choose to mate with that kind of animal even if that kind is not their own (read a discussion of imprinting elsewhere on this website).

Accounts of such behavior seem to be nothing unusual in the older literature. In closing, I'll quote one such case here (from Bingley 1820, pp. 247-248):

Some years ago a sympathy of this nature took place in the house of Mr. James Greenfield of Maryland, betwixt a Cat and a Rat. The Cat had kittens, to which she frequently carried Mice and other small animals for food; and among the rest she is supposed to have carried to them a young Rat. The kittens probably not being hungry played with it, and when the Cat gave suck to them, the Rat likewise sucked her. This having been observed by some of the servants, Mr. Greenfield was informed of it. He had the kittens and Rat brought downstairs and put on the floor; and in carrying them off the Cat was remarked to convey away the young Rat as tenderly as she did any of the kittens. This experiment was repeated as often as any company came to the house, till a great number of persons had become eye-witnesses of the extraordinary affection.

A related cross >>

A list of cat crosses

The following is a list of reported cat crosses. Some of these crosses are much better documented than others (as indicated by the reliability arrow). Indeed, some might seem completely impossible. But all have been reported at least once. The links below are to separate articles. Additional crosses, not listed here, are covered on the cat hybrids page.

reliability arrow

Table of contents >>

Bibliography >>

Internet citations >>

Biology Dictionary >>

By the same author: Handbook of Avian Hybrids of the World, Oxford University Press (2006).


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