How much do you really know about eastern grey kangaroos?
Eastern Grey Kangaroos (Marcrocarpus giganteus) are iconic Australian animals, commonly seen in our area, including at Gresswell Forest and in Banyule Flats.
A recent video popped up in my social media feed highlighting the winning ‘Dance Your PhD’ video competition from Weliton Menário Costa, a PhD researcher with the ANU Research School of Biology. Called ‘Kangaroo Time’ it’s a music video explaining the findings of his PhD, which found that kangaroos benefit from diversity in the individuals that comprise the mob and that their personalities are impacted by the social environment they are in.
It got me thinking, how much do I really know about them?
So here are a few interesting things that you might not know about Eastern Grey Kangaroos (well that I didn’t until recently anyway…!).
1. They can pause their pregnancies
A female kangaroo (a doe) has one live young (a joey) per year. Being a marsupial, it suckles in her pouch. However, she has the ability to put a fertilised embryo on hold, so as soon as the young is out of the pouch, she can birth another if conditions are good. This means she can have a joey in her pouch, another out of the pouch, plus an embryo on hold ready to birth as soon as the pouch becomes vacant.
2. They exist in complex social structures and appear to form long-term friendships
Research undertaken by UNSW published in Animal Behaviour last year, indicates that kangaroo relationships could be far more complex than previously thought. Using a huge dataset of more than 3000 photographs of a single group of Eastern grey kangaroos, taken over a period of six years researchers first needed to identify individuals. They used a computer program to identify 130 individual kangaroos using their unique ear shape. Using this tool (also used to track whales by the tail flukes) they discovered that individuals in the mob appear to form long-term friendships. This is particularly true of females with joeys who seek out other mothers with joeys. Researchers say this was unexpected as they appear to have a relaxed and loose social structure.
3. They can’t move backwards
Kangaroos are physically incapable of moving backwards, which is one of the reasons why they are on the Australian Coat of Arms – as a sign of moving forwards.
4. They are left-handed
Until recent years it was thought the only mammals that favoured one hand consistently were humans and some primates. However, research published in 2015 shows that 95 per cent of kangaroos show a preference for using their left paw for things such as grooming, bringing food to their mouth and stepping first with one paw. This ‘handedness’ seems to be a trait shared by all species of standing (bipedal) marsupials (including wallabies, bettongs and kangaroos), but is not the case with tree dwelling marsupials such as tree kangaroos nor marsupials that walk on all four legs.
Written by Jen Willis