Evan Switzer, a man from Hervey Bay in North Queensland, was taking his dog for a walk on Wednesday when he came upon a touching scene - a male kangaroo cradling the head of his dying mate.
He immediately dashed home to get his camera and when he posted the pictures, they went around the world. He thought he was witnessing an animal who was experiencing grief.
"The kangaroo tried to lift her up but she couldn't stand, she'd just fall to the ground....he'd nudge her, stand beside her....it was a pretty special thing......he was mourning the loss of his mate.
But the Australian Museum's principal research scientist Dr Mark Eldridge said he was trying to get her to stand so he could mate with her, and couldn't care less that she was dying.
"The male is highly stressed and agitated, his forearms are very wet from licking himself to cool down. He is also sexually aroused: the evidence is here sticking out from behind the scrotum, yes in marsupials, the penis is located behind the scrotum" Dr Eldridge said.
"So the male wasn't trying to prop her head up so she could see her joey before she died, this male was trying to get the female to stand up so he could mate with her."
Mr Switzer said the male had been trying his hardest for over an hour and chased off other kangaroos who came near, and now we know why.
"It will certainly give us something to talk about tonight at our camera club meeting tonight" he said.