Wallaby Birth Takes Taronga Zoo By Surprise

The joey’s father left the Zoo more than a year ago.

This must be the definition of a pleasant surprise!

Taronga Zoo keepers and visitors were surprised – and overjoyed – this week to discover the birth of an endangered Brush-tailed Rock-wallaby more than a year after its father left the Zoo.

The joey, who has recently begun peeking out of mum Mica’s pouch, is around six months old but keepers are yet to determine whether she’s a boy or girl.

“We weren’t planning for another joey, so it was quite a shock when we started seeing something moving inside the pouch,” said Keeper, Tony Britt-Lewis.

“Mica is a confident and attentive mum and her joey looks to be very strong. It shouldn’t be long before we start to see it venturing out of the pouch to take its first wobbly steps,” he said.

The birth is the result of embryonic diapause. Not virgin birth in the strict sense of the phrase, embryonic diapause happens when a mother puts a fertilised egg on hold in her uterus.

If environmental conditions aren’t right, the mother can prevent the fertilised egg from implanting and developing for a long period of time.

“It’s an interesting survival mechanism that allows the mother to delay the development of the embryo in drought conditions or if she already has a joey in the pouch,” said Tony.

Brush-tailed rock-wallabies (Petrogale penicillata) are listed as an endangered species in New South Wales.

Taronga’s breeding program will provide wallabies that can be reintroduced into the wild. Just last year, the zoo welcomed two other brush-tailed rock-wallaby joeys.

Visitors can look out for the joeys in Taronga Zoo’s Platypus Pools exhibit.

[Images: Paul Fahy, Taronga Zoo]

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