Lami tuco-tuco  (Ctenomys lami)

The Lami tuco-tuco is classified as Vulnerable (VU) on the IUCN Red List (1).

A burrowing rodent from South America, the most distinguishing feature of the Lami tuco-tuco (Ctenomys lami) is its incredibly large, prominent upper incisors (4). The Lami tuco-tuco is a stocky animal, with a large head and blunt snout. It has small eyes and its ears are little more than folds of skin around small openings on the sides of the head (4). The tail is short and cylindrical (5), and the limbs are stout and muscular (4).

The forelimbs of the Lami tuco-tuco are slightly shorter than the hindlimbs, and bear strong claws which are used to burrow, while the hindfeet are fringed with long hairs (4). This bristly, comb-like hair, which is used to groom soil from the fur following foraging, gives the species its scientific name, as Ctenomys means “comb-mouse” (6).

The name ‘tuco-tuco’ comes from the sound of this rodent’s bell-like call, which can be heard echoing up from its underground burrow (4) (7).

The lami tuco-tuco occurs only in southern Brazil, in the state of Rio Grande do Sul. Its small range extends from the north of Guaiba Lake to the north-western banks of Barros Lake (1).

The Lami tuco-tuco has very specific habitat requirements, occurring only in a sandy-soiled region named ‘Coxilha das Lombas’, which runs alongside a narrow line of old sand dunes (1). Within this habitat, the Lami tuco-tuco lives in burrows excavated in the sandy soil (7).

Although the Lami tuco-tuco is a relatively little-known species, its biology and life history is likely to be similar to that of other tuco-tucos (Ctenomys species).

Proficient burrowers, tuco-tucos excavate extensive underground networks of tunnels and chambers, which are typically never more than 30 centimetres below the surface (4). Heaps of soil at the surface, like molehills, mark the courses of the burrows (4). Although most species of tuco-tuco are solitary, with each adult occupying its own burrow, some species are known to live in groups in the same burrow system (8). Whether the Lami tuco-tuco is a solitary or gregarious species is not yet clear.

Tuco-tucos are herbivorous rodents, feeding solely on plant material. This includes roots and tubers (5) (8), which are probably pulled into the burrow from below ground (8), as well as stems and grasses, which the tuco-tuco has to venture above ground to collect (5). Tuco-tucos hoard food, storing it in chambers within the burrow system, and this food seems to provide all the water the tuco-tuco requires (4). Tuco-tucos are most active early in the morning and late in the afternoon, and spend the rest of the day in the burrow (4). Before venturing from the burrow, the tuco-tuco is able to check its surroundings for predators without exposing itself, as its eyes are almost level with the top of the head (8).

Female Lami tuco-tucos typically fall pregnant in the winter and give birth in the spring (3). The gestation period of tuco-tucos typically lasts 105 to 120 days, after which the female gives birth in a grass-lined chamber to up to seven young. The well-developed young are able to leave the nest and feed themselves shortly after birth. Tuco-tucos typically breed before they are a year old, but generally live no longer than three years (4).

The Lami tuco-tuco is threatened by the loss of its habitat due to the development of residential and commercial areas, as well as the conversion of land for agriculture, particularly rice and soybean cultivation (1) (9).

Hybridisation with the tiny tuco-tuco (Ctenomys minutus) also poses a serious threat to the future of the Lami tuco-tuco. The two species were once separated by a wide area of unsuitable humid habitat but rice farming has reduced this swamp area to a dry region that the two species can now both inhabit (1) (9).

In addition, due to their burrowing habits, tuco-tucos are often considered to be an agricultural pest and may be killed as a result ((9).

There are currently no known conservation measures in place for this endangered species (1). In Brazil, a lack of knowledge about tuco-tucos has contributed to difficulties in developing conservation initiatives (9), and so further research into this poorly known rodent has been recommended as a first step (1). 

Find out about wildlife conservation in Brazil:

• WWF – Brazil:
  http://wwf.panda.org/who_we_are/wwf_offices/brazil
• Conservation International – Brazil:
  http://www.conservation.org/explore/south_america/brazil