SCIENTIFIC NAME Dasypus novemcinctus

Taxonomy PHYLUM: Chordata CLASS: Mammalia ORDER: Cingulata FAMILY: Dasypodidae

Physical description


The armadillo, an ancient mammal that first appeared 65 million years ago, is currently represented by approximately 20 different species, the most common of which in the US is the nine-banded armadillo. It averages 0.75 m in length (including the tail) and 6 kg in weight. The armadillo boasts a unique carapace, or hard, protective outer shield encasing the body, covered with a dark brown keratin layer. Beneath this layer is a well organized arrangement of bony tiles that are closely compacted and connected by collagen fibers. The carapace is divided into five regions: head, pectoral, banded, pelvic shields and tail. The tiles are hexagonally shaped in the pectoral and pelvic regions and triangular along the mid-section.


The nine-banded armadillo is distributed from northern Argentina to the southern US, living in a wide range of environmental conditions. The armadillo is most active at dusk and during the night in order to avoid predators and extremes of temperature, though this varies with climate and seasonality. The nine-banded armadillo, compared with most eutherian mammals, has an atypical endothermy characterized by low and variable metabolic rates and body temperatures. Some armadillos are insectivores, but many species, like those of the genus Dasypus, also feed on fruits, roots and small vegetables. Armadillos swallow their prey together with soil particles, which provide iron1.

Research résumé

Certain characteristics of armadillos make them suitable models for studying host-pathogen interactions2: the animal produces litters of identical quadruplets (useful for control and experimental studies), has a relatively long life span of 10–15 years, tends not to bite, tolerates laboratory procedures and, in the US, is found in large populations. The armadillo has also been bred in captivity for research purposes.

Bacteria prefer the relatively low body temperature of the armadillo (32–35 °C), and armadillos are known to harbor several pathogens including Mycobacterium leprae, which causes the chronic infectious disease leprosy (Hansen's disease). Though often considered a disease of antiquity, leprosy remains an important public health problem throughout the word. If left untreated, leprosy can result in irreversible nerve damage with profound sensory and motor nerve loss, deformity and blindness3. Though significant progress has been made in reducing new incidences of the disease, improved diagnostic tests and treatments are still needed4.

A major obstacle in leprosy research has been the inability to cultivate M. leprae in vitro, making it difficult to produce sufficient quantities of the bacteria for testing. The only animal in which leprosy is reliably recapitulated is the nine-banded armadillo, which exhibits many of the clinical conditions that are associated with the disease in humans3.

In laboratories, armadillos are experimentally infected to help find effective vaccines and treatments for leprosy. Armadillos have been used to study both susceptibility and resistance to leprosy. One study with armadillos helped to identify antigens for early leprosy diagnosis, which can be used for screening programs in regions where leprosy is endemic3. Now that the Human Genome Consortium has completed the sequencing of the armadillo genome as part of a comparative genomics initiative, the availability of sequence information on the armadillo is likely to rapidly expand the availability of new immunological probes and reagents for use with armadillos and will advance their use as models for leprosy resistance and vaccination and nerve injury5.