From Wiki

"The Red Kangaroo (Macropus rufus) is the largest surviving marsupial anywhere in the world. Fewer in numbers, the Red Kangaroo occupies the arid and semi-arid centre of the continent. A large male can be 2 metres (6 ft 7 in) tall and weigh 90 kg (200 lb)."

Sorta like a low flying truck... right thru the windscreen... hence the perceived need for 'roo bars'...

I remember a series of cartoon jokes (may have even been T-shirts) years ago... one of them had a big red staring down a triple ganger road train with the caption "Roo-Ted"...