“This animal is known by the name of Tucutuco. I have given an account
of its habits in my journal, but I shall here repeat it for the sake of
keeping together my observations on the less known animals. The Tucutuco
is exceedingly abundant in the neighbourhood of Maldonado, but it is
difficult to be procured, and still more difficult to be seen, when at
liberty. Azara,[33] who has given an account of its habits, with which
every thing I saw perfectly agrees, states that he never was able to
catch more than one, although they are so extremely common. The Tucutuco
lives almost entirely under ground, and prefers a sandy soil with a
gentle inclination; but it sometimes frequents damp places, even on the
borders of lakes. The burrows are said not to be deep, but of great
length. They are seldom open; the earth being thrown up at the mouth
into hillocks not quite so large as those made by the mole. Considerable
tracts of country are completely undermined by these animals. They
appear, to a certain degree, to be gregarious; for the man who procured
my specimens had caught six together, and he said this was a common
occurrence. They are nocturnal in their habits; and their principal food
is afforded by the roots of plants, which is the object of their
extensive and superficial burrows. In the stomach of one which I opened
I could only distinguish, amidst a yellowish green soft mass, a few
vegetable fibres. Azara states that they lay up magazines of food within
their burrows.
“The Tucutuco is universally known by a very peculiar noise, which it
makes when beneath the ground. A person, the first time he hears it, is
much surprised, for it is not easy to tell whence it comes, nor is it
possible to guess what kind of creature utters it. The noise consists in
a short, but not rough, nasal grunt, which is repeated about four times
in quick succession; the first grunt is not so loud, but a little
longer, and more distinct than the three following: the musical time of
the whole is constant, as often as it is uttered. The name Tucutuco is
given in imitation of the sound. In all times of the day, where this
animal is abundant, the noise may be heard, and sometimes directly
beneath one’s feet. When kept in a room, the Tucutucos move both slowly
and clumsily, which appears owing to the outward action of their hind
legs; and they are likewise quite incapable of jumping even the smallest
vertical height. Mr. Reid, who dissected a specimen which I brought home
in spirits, informs me that the socket of the thigh-bone is not attached
by a ligamentum teres; and this explains, in a satisfactory manner, the
awkward movements of their hinder extremities. Their teeth are of a
bright wax yellow, and are never covered by the lips: they are not
adapted to gnaw holes or cut wood. When eating any thing, for instance
biscuit, they rested on their hind legs and held the piece in their fore
paws; they appeared also to wish to drag it into some corner. They were
very stupid in making any attempt to escape; when angry or frightened,
they uttered the Tucutuco. Of those I kept alive, several, even the
first day, were quite tame, not attempting to bite or to run away;
others were a little wilder. The man who caught them asserted that very
many are invariably found blind. A specimen which I preserved in spirits
was in this state; Mr. Reid considers it to be the effect of
inflammation in the nictitating membrane. When the animal was alive, I
placed my finger within half an inch of its head, but not the slightest
notice was taken of it: it made its way, however, about the room nearly
as well as the others. Considering the subterranean habits of the
Tucutuco, the blindness, though so frequent, cannot be a very serious
evil; yet it appears strange that any animal should possess an organ
constantly subject to injury. The mole, whose habits in nearly every
respect, excepting in the kind of food, are so similar, has an extremely
small and protected eye, which, although possessing a limited vision, at
once seems adapted to its manner of life.
“Several species probably will be found to exist south of the Plata. At
Bahia Blanca (Lat. 39°) an animal burrows under ground in the same
manner as the _C. Braziliensis_, and its noise is of the same general
character, but instead of being double and repeated twice at short
intervals, it is single and is uttered either at equal intervals, or in
an accelerating order. I was assured by the inhabitants that these
animals are of various colours, and, therefore, I presume that the two
kinds of noises proceeded from two species. However this may be, they
are extraordinarily numerous: many square leagues of country between the
Sierras Ventana and Guetru-heigue are so completely undermined by their
burrows, that horses in passing over the plain, sink, almost every step,
fetlock deep. At the Rio Negro (Lat. 41°) some closely allied (or same?)
species utters a noise, which is repeated only twice, instead of three
or four times as with the La Plata kind. The sound is, moreover, louder
and more sonorous; and so closely resembles that made in cutting down a
small tree with an axe, that I have occasionally remained in doubt for
some time to which cause to attribute it. Where the plains of Patagonia
are very gravelly (as at Port Desire and St. Julian) the Ctenomys, I
believe, does not occur; but at Cape Negro, in the Strait of Magellan,
where the soil is damper and more sandy, the whole plain is studded with
the little hillocks, thrown up by this destructive animal. It occurs
likewise south of the Strait, on the eastern side of Tierra del Fuego,
where the land is level. Captain King brought home a specimen from the
northern side of the Strait, which Mr. Bennett[34] has called _C.
Magellanicus_: it is of a different colour from the _C. Braziliensis_. I
unfortunately did not make any note regarding the noise of this southern
species: but the circumstance of its existence rather corroborates my
belief in there being several other kinds in the neighbourhood of the
Rio Negro and Bahia Blanca. Otherwise we must believe that the same
animal utters different kinds of noises, in different districts; a fact
which I should feel much inclined to doubt.
“Azara[35] says that the Tucutuco may he ‘found every where; provided
that the soil be pure sand, and the situation not subject to be
overflowed. As these conditions are fulfilled only in certain spots,
their warrens are far separated from each other, even sometimes more
than twenty-five leagues, without it being possible to conceive how
these animals have been able to pass from one place to another.’ The
difficulty, I think, is much overstated; for, as I have said, the
burrows of the Tucutuco are sometimes made in very damp places, near
lakes; so that they certainly might pass over almost any kind of
country. But if the _C. Braziliensis_ and _C. Magellanicus_ be
considered as one species, as some French authors are inclined to do,
then the difficulty will be increased in a very remarkable manner, as we
shall be obliged to transport the Tucutuco over wide plains of shingle,
and across many great rivers, and an arm of the sea.”—D.