Reproduction and Growth in Captive Punare (Thrichomys apereoides Rodentia: Echimyidae) of the Brazilian Caatinga with Reference to the Reproductive Strategies of the Echimyidae

Thrichomys apereoides has a body mass (ca. 350 g), mean litter size (3.2 ± 1.3), neonatal growth rate, mean neonatal mass (21.1 ± 4.7 g), and weaning age (ca. 6 weeks) similar to that of other echimyids studied to date. However, it differs strikingly from other echimyids in having a 40% longer conception-to-weaning period, a 50% slower prenatal growth rate, an approximately 50% longer gestation period, a 10% lower basal metabolic rate, an extended generation time, and lower lifetime reproductive rate. These differences appear to be adaptations for, and consequences of, minimizing maternal energy expenditures for reproduction while maximizing reproductive output and offspring survival in a harsh and unpredictable environment.