Cat × Red Squirrel

Felis catus × Sciurus vulgaris

Hybrids out of History


I am obliged to report that which is reported, but not to believe it.
The History, VII, 152
reality thermometer
Reality Thermometer (estimated reliability of this cross).

A seventeenth-century German physician, Gabriel Clauder (1633-1691), published a brief article (Clauderi 1686) in the medical journal Ephemeridum Medico-Physicarum Germanicarum Academiæ Naturæ Curiosorum, an account cited by a variety of later authors (e.g., Blumenbach 1781, p. 10; Broca 1859). Clauder’s report gives a description not of a cat-squirrel hybrid as such, but rather of what seemed to be a pure squirrel birthed by a cat after copulation with a male squirrel.

However implausible this report may be, it reads as follows: “On a Cat giving Birth to a Squirrel—It is certain that both the highest miracles and daily novelties, as well as numerous sports and alterations, arise

Note: It has been my policy in listing reports of hybrids to include all serious allegations, especially those of 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 remove at least one source of systematic bias from my work. It also helps to fulfill the ethical obligation of telling not just the truth, but the whole truth.
Sciurus vulgaris
Eurasian Red Squirrel (Sciurus vulgaris)
Credit: Peter Trimming (Wikipedia)
from Nature’s depths, which no human can copy. And out of a diversity of cases, a single instance will suffice to demonstrate this fact: A domestic cat after coitus with a squirrel gave birth to three kittens like herself and to one squirrel. This squirrel, which on account of its rarity was kept as a pet by a most illustrious personage, did not in any way resemble its mother, nor were the feline offspring in the least like their father." [Translated by E. M. McCarthy. Original Latin: “Felis Sciurum pariens—Summe miraculosos ac quotidie quasi novos e Natura abysso lusus ас metamorphoses modis in numeris parefieri, certissmum est, quas describere, non eft humana crenae opus. Ob diversas causas unica hic sufficiat talis historia: Felis domestica à coitu cum Sciuro parit tres catos sui generis & unum Sciurum; dictus Sciurus ob raritatem a Viro illustrisummis in deliciis haditus, ne minima Naturae matrissantis indicia prae se ferebat; veluti quidem catuli felini ne minimum patrisabant.]

Presumably the squirrel in question would have been a Eurasian red squirrel (Sciurus vulgaris), the only common squirrel in Europe at that time.

Video: A cat and a squirrel make friends

That a squirrel and cat might mate is not so improbable as one might suppose. As can be seen in various YouTube videos—for example, the upper video at right—it can be seen that at least some squirrels and cats get along quite well, especially when they are raised together. The video just mentioned is somewhat surprising because it apparently shows a wild squirrel cavorting with a tame cat.

Video: Cat adopts and nurses a baby squirrel

Indeed, as peculiar as it may seem, it’s a fact that cats, at least some cats, have been known to adopt and nurse young squirrels (as shown in the video at right), which is significant in the present context, given that most mammals imprint on the type of animal that raises them. In other words, 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).

Considering the various videos available on YouTube showing cats nursing squirrels, it’s clear that the behavior documented in the particular video on this page is by no means unique. And seemingly, those who study animals have long been aware that such things do on occasion occur. Thus, an early nineteenth-century naturalist, William Bingley (1820, pp. 247-248) states the following: “A boy, says [the Rev. Mr. White of Selborne], brought to him three young Squirrels, which had been

taken from their nest. These little creatures he put under a Cat that had recently lost her kittens; and he found that she nursed and suckled them with the same assiduity and affection as if they had been her own progeny. So many persons, however, went to see the little Squirrels suckled by a Cat, that the foster-mother became jealous of her charge and in pain for their safety and therefore hid them over the ceiling, where one of them died.
Gabriel Clauder
Gabriel Clauder

Clauder’s account is unsubstantiated hearsay, but he did publish it in a medical journal. So perhaps it was a real event. If so, it’s interesting to speculate what might have happened. One explanation is that it might have been a rare instance of a phenomenon in which a cat ovum, penetrated by a squirrel spermatozoon, rescued itself by doubling the squirrel genome and eliminating the haploid cat genome so that the fertilized zygote became diploid squirrel and developed as such. (Presumably the remaining individuals in the litter, which were all ordinary cats, would then be the separate products of an ordinary insemination with cat semen.)

But, of course, at this distance in time there really is no way of knowing whether Clauder’s squirrel actually was birthed by a cat. So I just record this report as an interesting phenomenon that someone else might be able to account for in time.

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.

sheep-pig hybrid
Sheep-pig hybrids?
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).

Most shared on

Human Origins: Are we hybrids?

On the Origins of New Forms of Life

Mammalian Hybrids

Cat-rabbit Hybrids: Fact or fiction?

Famous Biologists

Dog-cow Hybrids

Georges Cuvier: A Biography

Prothero: A Rebuttal

Branches of Biology

Dog-fox Hybrids

Cat × Red Squirrel - ©