Popular Science Monthly/Volume 5/August 1874/A Baby-Fox
By Dr. BURT G. WILDER.
MY readers may have heard of the artist who, finding that his portrait of the "king of beasts" was not often recognized, indignantly wrote beneath it, "This is the picture of a lion." Something of like necessity exists with reference to the figure in the present article; for it is doubtful whether any one, not already familiar with fox-babies, would recognize it as the picture of one; to use the words of another, this is an "odd, snub-nosed little creature, resembling almost any animal rather than a fox."
Yet the non-recognition cannot, in this case, be ascribed to any defect in the representation; for the original drawing was made by an anatomist and engraved by one whose previous work upon natural history objects has convinced him of the need for accuracy and restraint of the artistic imagination.
Certainly the non-resemblance of the little one to its mother would have been enough to shake my belief in the statement of relationship, had not both the specimens and the statement come together from a naturalist who received them direct from the hunters; and my first impulse was to publish the figure incognito as a zoological conundrum.
The most obvious difference is in color: the throat and chest of the old fox are whitish, also the tip of the tail; the back of the ears, the front and outer surface of the paws to near the elbows and knees, are black, and there are scattered black hairs on the tail; the rest of the body is reddish brown; and as a whole the animal would be called a "red fox," although a stripe across the shoulders of a darker red might entitle it to the name of "cross" fox. Now, at first sight, all the young would be called "black," although the head and shoulders are brownish, and the tail is tipped with white.
In this connection it is to be noted that Audubon and Bachman had once a mother and a litter of seven young foxes; the former was nearly jet black, with the tip of the tail white; three of the young were said to be black, the other four red; one of the blackest was kept alive for six months, and as it grew older the less it became like the "black," and the more like the "cross" fox; whence they conclude that both the "cross" and "black" foxes are mere varieties of the "red;" in this opinion Mr. J. A. Allen concurs.
But there is something more to be said of our little fox and its mother: a closer examination of the former shows that there are two kinds of hair corresponding to the two colors; the body and tail, and upper parts of the legs, are thickly covered with a kind of soft wool, of a smoke-color, but the head presents longer and reddish-colored hairs; and these same hairs are scattered over the body, more thickly in front than behind; the two kinds are as thick brush-wood and saplings; under the microscope they are even more unlike; for the "wool" is crinkled, and its texture very transparent; the pith seeming to be divided by transverse partitions into a single row of nearly square spaces; the hairs, on the other hand, are straight, and two or three times as thick, and their texture much more dense, apparently from a crowding of the partitions and interspaces; and one thing more, the hairs are reddish only as far as they project above the wool, the deeper portions, like the wool, being smoke-colored. Now, the same is the case in the old fox, with this difference, that the hairs are so long and so numerous as to completely hide the woolly coat, and so give their own color to the animal; the wool presents the same appearance under the microscope as in the young one, and seems to be little if any larger, but the hairs are at least ten times as thick at their base, and taper thence gradually to the tip. We may easily imagine, then, not only that in some cases the long hairs themselves might be black throughout, but also that, as in the case mentioned by Audubon, an increase of the number of reddish-tipped hairs during growth might convert an apparently black fox into a red one.
Finally, it is certain that, were the old fox to lose her hairs and retain only the wool, she would be as black as her young, excepting, perhaps, upon the head.
After the color, the next most striking difference between the old and young foxes is the form of the head: that of the former is remarkable for its length, and for the total lack of forehead, the upper surface being all on a level from the tip of the nose to the top of the head; while the frontal region of the young is quite prominent. The change in the form of the head is better shown by a comparison of measurements:
|Distance from tip of muzzle to a point between the ears||.050,||||.150,|
|Distance from tip of muzzle to a point between the eyes||.022,||.075,|
|Width of the head opposite the eyes||.042,||.075,|
From the above we see that in the adult fox the muzzle proper is half the length of the head from the ears forward, and that the width of the muzzle from its base (opposite the eyes) is equal to its length; while in the young the length of the muzzle is less than half the length of the head from the ears, and little more than half the width of its base; so that even without the figure we should see the justice of Wood's description of the little fox as "snub-nosed."
But the figure or the specimen itself would be required to corroborate his other remark, that it "resembles almost any other animal rather than a fox."
Now, it certainly does not resemble a fox; and among dogs it could be compared only to the young, or to some of the smaller breeds. But it does remind one irresistibly of certain dog-faced monkeys or baboons; and to some degree, as Dr. Barnard suggests, of the lemurs. In either case it is worth while to bear in mind that the gap, hitherto supposed to exist between the Carnivora and the Quadrumana, has been partly bridged over by the researches of Milne-Edwards upon the "Embryology of the Lemuridæ;" these curious little creatures, inhabiting the islands of Mauritius and Madagascar, and the adjacent coast of Africa, have been ranked as a subdivision of the Quadrumana on account of their arboreal habits, their prehensile limbs, and some anatomical resemblances to the monkeys; but an examination of their placenta has convinced Milne-Edwards that they are quite as nearly allied to the Carnivora as to the Quadrumana and that they should form a distinct order between and connecting the other two; and this conclusion, he says, is supported by a comparison of the brain, the limbs, the skull, and the teeth.
Now, if this be correct, and if we admit that in some way our existing species have been derived from other and preëxisting forms, then it is not at all difficult to account for the resemblance of our little, fox to a monkey, or of certain monkeys to dogs, upon the supposition that both groups of animals, the Quadrumana and the Carnivora, are divergent branches from a common stock, resembling the lemurs more than either of them.
But, aside from such speculations as to the reason for the differences above alluded to, their existence is undeniable; and it is surprising to find how very few are the figures and descriptions of young mammals; the last scientific letter written me by Prof. Agassiz (September 10, 1873) strongly urged the importance of including, within the embryology of domesticated animals, the changes which they undergo after birth; and he particularly requested that the dogs, and the wild canidæ as well, should serve as the starting-point. Enough has been said to show that these changes are very great in the fox, and that they may furnish suggestions at least, as to origin and natural relationships.
- Wood's "Illustrated Natural History of Mammalia," p. 334; it is not often that so compact an expression occurs in these usually verbose volumes.
- My friend and former pupil, Dr. W. S. Barnard.
- Mr. Philip Barnard, of Chicago, now a student in Cornell University.
- Dr. J. T. Rothrock, of Wilkesbarre, Pennsylvania, now attached to one of the United States surveying expeditions.
- "Quadrupeds of North America," vol. i., pp. 52, 53.
- "Catalogue of the Mammals of Massachusetts;" "Bulletin of the Museum of Comparative Zoology," No. 8.
- In the "Natural History of the State of New York," De Kay says (p. 45) that the young are at first covered by smoke-brown fur.
- This is fifty millimetres (a trifle over two inches); the full stop is placed after the place for the number of metres, the unit of the measure of length; a comma is placed after the millimetres, thousandths of a metre. The old fox weighed 2,918. (two thousand nine hundred and eighteen grams, the full stop coming after the number of grams, the unit of weight), or about 61 pounds; she was rather thin; foxes are sometimes taken weighing 10 and 11 pounds, but usually about 9; the young weighed about 15 ounces each (avoirdupois); ,375. ,377. and ,417. grams respectively; their eyes were not fully opened; all their ears were injured either by frost or the bites of dogs, and their form is uncertain.
- "Annales des Sciences Naturelles," Fifth Series, vol. xv.