Comparisons between nine-banded armadillo (&lt;i&gt;Dasypus novemcinctus&lt;/i&gt;) populations in Brazil and the United States

Colleen M Mcdonough,W J Loughry

doi:10.15517/rbt.v46i4.20740

Abstract

We compared characteristics of a population of nine-banded armadillos (Dasypus novemcinctus) studied in the soulhem Uniled States with a population found in the Atlanlic coastal rainforest of Brazil. Adult armadillos in Brazil weighed less than Ihose in Ihe U.S., but when weight was accounted for, did not differ in: other measures of body size. However, juveniles in Ihe U.S. were proportionately bigger!han Ihose in Brazil. Armadillos in Brazil were less abundant (numbers sighted per h of observation) and were active laler al night .!han Ihose in the U.S. Adult sex-ratios were male-biased in bolh populations: Finally, there was no significant difference in Ihe incidence of litterrnate associations observed in Ihe two populations, but groups of juveniles (which included non-Iitterrnates) were observed more frequently in tbe U.S. Many of Ihese differences may be due 10 the fact that armadillos are hunted extensively in Brazil but not in the United States.

Highlights

Many charactersitics of animal populations vary. intraspecifically, presumably as the result of adaptation to conditions that vary geographically (Lott 1991, Foster and Endlerin press)
Comparisons with non North American populations of D. novemcinctus are required to determine if this is a legitimate concern. We addressed this issue by collecting data on a population of nine-banded armadillos located in northern Florida (Loughry and McDonough 1996, McDonough and Loughry 1997a) and, using the same methods, a population located in the Atlantic coastal ra¡nforest of BraziL These two data sets provide an opportunity to examine the question of how similar armadillos are in these two widely separated locales
While our data are not an exhaustive account of the population attributes of armadillos in either location, they allow at least a preliminary assessment of the extent of intraspecific variation that can occur in D. novemcinctus

Summary

Introduction

Many charactersitics of animal populations vary. intraspecifically, presumably as the result of adaptation to conditions that vary geographically (Lott 1991, Foster and Endlerin press). The extent of intraspecific variation provides information on how generalizable data from one population are to populations in other parts of a species' range. Nine-banded armadillos (Das)'pus novemcinctus) are found from northern Argentina to the southern United States (Humphrey 1974, Wetze1 1982, 1985, Taulman and Robbins 1996). Nine-banded armadillos have only recently colonized the U.S (Humphrey 1974, Taulman and Robbins 1996), so data from these studies may not be representative of populations in more ancient parts of the species' range, living in the kinds of conditions under which the species presumably evolved. While our data are not an exhaustive account of the population attributes of armadillos in either location, they allow at least a preliminary assessment of the extent of intraspecific variation that can occur in D. novemcinctus

Methods

Results

Conclusion