I can’t imagine that wild cats would make an appreciable dent in a wild kangaroo population.
I think more mudane problems like disease (mentioned extensively upthread), habitat adoption, food sources and water access would be much greater factors. Is Australian and African scrub/grassland essentially identical? Is the terrain similar enough that they would be comfortable?
A gut feeling is that they’d have a pretty good chance if you had a sufficiently large initial herd and the first year didn’t have extreme weather while they found out ways to survive.
Lions have been known to take down elephants, so I think a kangaroo would be no problem. And assuming you are talking about red kangaroos (the largest species), why do you think a lion couldn’t reach its windpipe, especially with two other lions clamped onto its backside?
A lion wouldn’t even need to reach its windpipe… it could probably kill a kangaroo accidentally just from the impact of the initial attack, without piercing anything. I think some posters are mistaken on the scales involved, here. Kangaroos are tiny compared to normal lion prey.
It must have been a semi tame on for the rednecks to get close enough to it.
I’ve hunted Roos on foot up in the bush when I was young. If a mob of Roo’s twigged you sneaking up on them they’d bolt and are bloody quick. Once they took off you had zero chance of catching them on foot.
On the other hand, in areas where they aren’t hunted and are used to human presence as being non-threatening (like a national park) they can be almost tame, allowing humans to get very close to them. I have a small section of enclosed “forest” near my house maintained by a local uni that has walking tracks through it. The Roos will lay there and watch you walk past at a distance of a couple of metres.
