The golden-backed tree-rat (Mesembriomys macrurus) (Peters 1876): reproduction, growth, development and behaviour in captivity

Abstract

The golden-backed tree-rat (Mesembriomys macrurus) is a large semi-arboreal rodent that has suffered a significant reduction in range since European settlement. Seven (three male, four female) founding adults for a captive colony were captured on the Mitchell Plateau, Western Australia, and transferred to Alice Springs, Northern Territory. The reproduction, growth, development and behaviour of M. macrurus in captivity were recorded. Twenty-three litters were born with litter size of 1–3 (median litter size: 2; overall sex ratio parity). There was no apparent seasonality in breeding. Oestrous cycle (9.9 ± 0.4 days) and gestation (46.8 ± 2.8 days) were estimated from known births and birth dates determined from calculated growth curves. Mean weight at birth was 17.2 g (±1.3, n = 12) and growth of the young was rapid, with head length reaching the asymptote from 54 days and head-body length from 83 days. Young were weaned at about 40 days and adult pelage complete by 98 days. Reproductive maturity occurred from 5 to 6 months for females and in males testes became scrotal from 76 days. Developmental stages and captive behaviour were also recorded. These results are compared with reproduction and growth of the closely related black-footed tree-rat (M. gouldii) and brush-tailed rabbit-rat (Conilurus penicillatus).