It’s hard to know what a cassowary egg looks like when the male guarding it round-the-clock is considered one of the world’s most dangerous birds.
However thousands of people following USC Australia’s Twitter account have this week learned that cassowary eggs are a shade of green that would even impress Dr Seuss fans.
Five eggs will be used by USC researcher Clancy Hall to determine the genetic sex of chicks before they hatch, in the hope of supporting more sustainable breeding programs aimed at restoring endangered Southern Cassowary and threatened Coastal Emu numbers in the wild.
First, she tested her “candling” technique on the notoriously thick and opaque shells of emus, by shining a light through a carefully sanded section of egg to take DNA samples. Now she’s trying it on the almost equally large cassowary egg in the 50-day window before they hatch.
“There’s only a handful of pigments present in bird eggs and I think the cassowary has the most brilliant in colour,” said Ms Hall, a PhD Ecology student supervised by Lecturer in Animal Ecology Dr Dominique Potvin.
“I don’t think it is common knowledge that their eggs are a such a chartreuse green. When they are incubating, the males sit tightly and rarely leave them unattended. When approached, they are fiercely protective and formidable, using a 12cm-long middle claw to inflict damage on predators,” Ms Hall said.
A photo, taken by a scientific colleague, of the current clutch of eggs has attracted more than 800 retweets on Twitter, with many comparing them to the iconic eggs from the Game of Thrones TV series.
The cassowary is the world’s third tallest bird (up to 1.8m) and second heaviest at up to 85kg. Believed to be one of the closest living relatives of dinosaurs, it can jump up to two metres high. It is considered a keystone species because it scatters the seeds of fruits across the rainforest floor.
“By learning the gender of emus or cassowary ahead of time, we are able to ethically hatch a desired sex,” Ms Hall said. “This will help maintain sustainable captive breeding populations to act as insurance for their wild counterparts.
“For instance, there are only 40 to 100 Coastal Emus in Central and Northern New South Wales, so this technique could help build a robust captive insurance population to later return to improved areas of wild habitat.”
“For instance, we know the breeding success of captive cassowary improves significantly when females can choose between two males. This technique would allow managers to strategically build a population that gave more males this opportunity,” Ms Hall said.