ESTABLISHMENT OF A CAPTIVE COLONY OF BETTONGIA-TROPICA (MARSUPIALIA, POTOROIDAE) BY CROSS-FOSTERING AND OBSERVATIONS ON REPRODUCTION

It is demonstrated that cross-fostering is a practical way of improvin g the rate of increase of a rare species in captivity. Two adult Betto ngia tropica were captured in northern Queensland and housed in captiv ity in Adelaide, South Australia. Eleven pouch young born in captivity to the wild-caught B. tropica were transferred at 20 days old or olde r to B. penicillata foster mothers and nine were reared successfully. Of a further 10 young not fostered, six were reared by the wild-caught mother. Fostering allowed the wild-caught female to produce surviving young nearly twice as frequently as if she had reared them in her pou ch. Sexual maturity occurred at 246-523 days ((x) over bar = 407.2 +/- 59.9 days) in 4 males and at 185-429 days ((x) over bar = 300.5 +/- 2 6.0 days) in 11 females. Breeding continues throughout the year and fe males undergo embryonic diapause whilst supporting a pouch young. The female reproductive system is remarkable for its relatively long ureth ra and lateral vaginae and consequently short urogenital sinus. The ma le reproductive system is unremarkable, having a carrot-shaped prostat e gland and three pairs of Cowper's glands, as do many other macropodo id species. Two pairs of paracloacal glands are found in males and fem ales.