American muskrat. Amphibious animal of North America, in the class of animals that gnaw. The muskrat and the beaver resemble our rat in shape, but it is much fatter, weighing three or four pounds, and smelling strongly of musk; it is brown in color; it is covered with two types of fur, one of which is longer, and the other shorter and very fine, similar to down; its teeth number twenty; its tail is covered with scales surrounded by numerous short bristles on the sides; its toes number four.

The muskrat is so similar to the beaver that the savages say that they are brothers, but that the beaver is the elder, and that he is smarter than his younger brother. It is true that at first glance one would take an old muskrat and a one-month old beaver for two animals of the same species. These rats are common in Martinique and in all the regions of Canada. The public is indebted to M. Sarrazin,  [1] who was King’s Physician in Quebec in 1725, for the detailed knowledge of their life, their structures, and what was most difficult to describe, their complete anatomy.

M. de Réaumur has presented a summary from various papers that M. Sarrazin sent him about these animals in the collection of the Academy of Sciences for the year 1725; [2] and for this article, I, in turn, am going to draw on M. de Réaumur’s summary, which will keep me from getting lost in the details, and which seems to me sufficient to satisfy the curiosity of readers.

Muskrats feed during the summer on all sorts of plants, and during the winter on different types of roots, such as those of the large white and yellow water lilies, and especially of the fragrant calamus. [3]

They live in groups [ en société ], at least during the winter; they build cabins for themselves, smaller ones, inhabited only by a single family; and larger ones, which contain several. Their genius shows even in the choice of the location where they establish themselves; it does not suffice that they be sheltered by their buildings during the winter, they must be within range of the water, and convenient to the roots on which they feed; I know many castles built contrary to these two rules of location, which the muskrats always follow.

To consolidate these advantages of which I have just spoken, they construct their lodges in wetlands, or on the edges of lakes and rivers, where the bed is flat, the water still, and where the land produces abundantly the roots on which they feed; it is on the highest points of such terrain that they build their lodges, so that the water can rise without disturbing them.

The choice of a site made, they prepare the place that the interior of the edifice they are planning should occupy and which will serve as a bed during the winter. If the place is too low-lying, they raise and lower it; if it is too high, they lay it out in tiers in order to be able to withdraw from level to level as the water rises. Their house is more or less large depending on the number of rats that will occupy it; when it is only designed for seven or eight, it is around two feet in diameter in all directions; and it is proportionally larger when it must contain more.

The lodge they inhabit forms a dome and is composed of woven rushes, and coated with clay that has been well soaked. With regard to the order in which their work is conducted, the manner in which they apply the earth and smooth it out, all we know about it is from what hunters say; and what these sorts of people say does not at all qualify as the observations of physicists, in whom we would have some faith. All that we know for certain, because we see it, is that the muskrats prepare an opening in their domiciles through which they can come and go; but they seal it up completely when winter announces itself.

As their constitution is not similar to that of those animals who do not eat at all, and who have no needs at all during the winter, these, by contrast, beyond the main body of the building, make room for the conveniences that are essential to them. They make wells that communicate with the interior of their lodges, where they can go drink and bathe. They dig galleries under the earth, or to speak less nobly, holes like those of moles, in order to go search for roots to live on in the snowy season. In a word, they don’t forget anything relevant to their needs and their cleanliness, even going so far as to furnish themselves with toilets [ lieux à l'angloise ] of a sort.

Springtime, their mating season, is often fatal for them. Hunters, those unjust murderers of the majority of animals, whistle for the males, and imitate the females, who have a sort of whine; by this ruse they get them to come to them, and they shoot them. Those animals that escape them return to their lodges, especially the females, who are a timid sex. However, most of them have their babies wherever they find themselves, but in hidden places. The males continue to run about the countryside; this is the way they live throughout the summer. When it is over, the time to make new cabins returns, since the same ones are not serviceable for several years; finally, they take up winter life again. The muskrats that live in the warmer parts of America don’t have the same need for cabins; thus they are burrowers like rabbits.

Dissecting them is not easy; there are few brains capable of withstanding the constant effect of such a strong odor of musk as that which this animal spreads. M. Sarrazin was twice driven to extremity by the effect that this penetrating odor had on him. We would have few anatomists, and we would not be able to complain about it, if it were at such a price. The savages who are affected just as disagreeably by the smell of musk as our hysterical women, for this reason call our rat the stinky animal.

It has, like the beaver, two sorts of fur; the longer is ten to twelve lines long, [4] brown, and gives its color to the animal. The shorter is a type of very fine down, which used to be used in its capacity as short fur, in the fabrication of hats. It protects the rat from the cold, and the long fur, which is coarser, protects the down from the muck, in which it often wallows, especially in building its lodge.

Its back is formed of nine vertebrae up to the root of the tail; its ears are short, rounded at the end, and velvety; its eyes are almost as large as those of the beaver, although the latter is at least fifteen times fatter; each of its two jaws is furnished with ten teeth, eight molars and two incisors, which makes twenty teeth in all.

The muskrat is a great gnawer. M. Sarrazin put one in a cage who, in a single night, pierced a hole in the hard wood three inches in diameter and a foot in length, by which he escaped. Its tail is covered in scales that overlap somewhat and that are surrounded by short hairs.

Its chest is very narrow from above; its ribs are twelve in number, six true and six false; its liver is composed of seven lobes, in one of which is situated the gallbladder, which opens into the duodenum; its intestines are very narrow, and are around six feet long; its stomach is fairly similar to that of the beaver from the outside, and somewhat to that of the domestic rat ; its esophagus is lined with a white membrane, which sometimes covers its stomach; there is nothing special about its bladder; but the end of the urethra in the female rat and in the familiar species of rats , that is, the water rat , the domestic rat , is very different from that of other animals.

The variety that we find in animals can be organized into three classes according to how urine flows. The beaver, and all the birds that have only one opening under the tail, present examples of the first type. All the land animals, except the beaver, of which we have just spoken, present examples of the second type; in them the urethra conducts the urine through the slit of the private parts, where it ends. Our female muskrats present examples of the third variety; they have three outlets; specifically, the anus, the slit of the private parts, and the hairy protuberance, or follicles situated on the pubic bone, through which the urethra conveys the urine.

The generative parts of the female muskrat are similar to that of the female domestic rat ; they have six teats, that is, three on each side, and they have up to five or six young.

The follicles of which we have just spoken are located above the pubic bone. They are found in both the male and the female. Canadian men call them muskrat kidneys ; and Canadian women, out of modesty, call them buttons . They all believe that these are its testicles. The hunters remove the follicles of the muskrats , male and female, during the rutting season; at the same time, they cut off a bit of skin, in which they wrap them to sell them; these follicles are shaped like a small upside down pear. They are composed of a cluster of glands wrapped in membranes furnished with veins and excretory ducts which apparently supply the humor that they contain.

This humor resembles milk, both in its consistency and in its color. It cannot be doubted for a moment that the scent of musk, which the muskrat exudes, comes from it. M. Sarrazin believed that it was passed to it from the fragrant calamus, on which it ordinarily feeds. Clusius also attributed the musky odor of the rat that he described to this plant. [5] Which seems to prove that it contributes a lot to that of ours, that its smell is stronger at the end of winter, when it has lived on practically nothing but this plant, than during the summer and autumn, when it feeds indiscriminately on various other roots. But whatever its food might be, in all likelihood a fermentation takes place in this animal when mating season arrives that exudes this scent.

The penis is attached by its root to the lower lip of the pubic bone. The glans has three or four bones, which can move in all directions. The testicles are the size of a nutmeg and located next to the anus. The seminal vesicles appear fully when in rut; they are so firmly attached under the pubic bone that it must destroyed in order to see them well; they are about an inch long; these vesicles probably function as prostates. But one thing that is quite singular, and perhaps unique to the muskrat , is that to the degree that its passion weakens, most of its generative organs fade, the testicles, the epididymis, and the vesicles begin to wilt.

Its forefeet resemble those of all gnawing animals; the rear ones do not resemble at all the feet of the domestic rat , or those of the beaver, or the muskrat described by Clusius. He says that the hind feet of this latter animal are covered by membranes; on ours, the toes are separated from one another, and a membrane runs the length of the sides of each toe, and is covered with rough hairs; such that the toes, the membrane, and the hairs arranged just so, form an instrument appropriate for swimming, but which however, is not as effective as the beaver’s foot; thus it does not swim as fast. It walks on rushes, but much less than the beaver and the river birds do; this movement is aided by a muscle that pulls the leg and the thigh behind. Its strength in swimming is increased because it describes with its paw a curved line, which consequently is longer than if it were straight. This strength also depends a lot on the way in which its paw is turned; what I mean is that it is behind, and pushes evenly against the water.

The rat of the Alps of M. Rey, [6] is that of Europe which in its exterior conformation resembles most the American muskrat . Sometimes we are sent the dried kidneys of this animal from Canada, which are called musk kidneys ; but our perfumers hardly use them at all anymore.

1. Michel Sarrazin (1659-1734), who arrived in New France with the French Navy in 1685 and remained there until his death of smallpox in 1734.

2. René Antoine Ferchault de Réaumur (1683-1757), a distinguished member of the French Academy of Sciences with a wide range of scientific interests. For a recent fascinating study of him see Mary Terrall, Catching Nature in the Act: Réaumur and the Practice of Natural History in the Eighteenth Century (Chicago, 2014).

3. Acorus calamus, also called sweet flag. It is a type of cane. However, it is apparently only an Old World plant, mentioned in the Bible.

4. The line was 1/12 of an inch.

5. The reference is to the early modern botanist Carolus Clusius (Charles de l’Ecluse; 1526-1609).

6. The rat of the Alps is the marmot. I have not been able to identify Monsieur Rey.