Most people have a friendly magpie, or maybe a kookaburra that frequently arrives on the verandah for bacon scraps. Not the McArthurs.

A fortnight ago, an emu followed them home as they were mustering cattle on horseback at their central Queensland property.

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"Everyone was a bit cautious of him at first, he's a rather large bird, we felt a little anxious about it," Rob McArthur said.

"He parked himself at the milker yards, Ainsley walked over, opened the gate and let him in, and in he came."

But despite the unusual start to life with the McArthurs, the emu, dubbed 'Fred' by the McArthur kids, seemed quite content with the new arrangement.

Fred the emu has been keeping a close eye on the children's schooling. ( Supplied: Ainsley McArthur )

"He'll walk around [the house yard], pick a few mulberries off the mulberry tree. We've still got some fairy lights up, he's quite fascinated with them, he's so tall he can reach up, picks at the lights hanging down from the verandah," Mr McArthur said.

"He's been rather like a pet, he'll go and have a camp and when he sees you he'll meander over."

An emu adopts a farming family in Queensland, in a situation which one expert says "is not even slightly normal". ( Supplied: Ainsley McArthur )

Fred's antics have been to the amusement of the McArthur clan, particularly when he chased some calves Mr McArthur was mustering out of the paddock.

"He turned and he looked and then he did a pirouette and then he took off … did a couple of goose steps, or emu steps," Mr McArthur said.

But Mr McArthur said it is still a mystery as to why he is so at home in their yard.

"When we walk out, when he comes over he makes his emu sound, it comes from deep in his throat, it's like he's greeting us," he said.

"But I have no idea why he's so friendly or quiet."

Emusing behaviour

Professor of ecology at Griffith University, Darryl Jones, was stumped by Fred's social behaviour.

"It is normal and sensible for most wild animals to be fearful of humans," he said.

"There are plenty of good reasons why an emu should be apprehensive about hanging out with people, but that doesn't seem to be the case here."

The peculiarity of the situation is not lost on Mr Jones, who said it is downright bizarre.

"This [behaviour] is not even slightly normal; this is very, very, very unusual and totally intriguing," he said.

Fred the emu is enjoying being part of the McArthur family. ( Supplied: Ainsley McArthur )

"Why isn't it scared of people? Has it had some sort of interaction before which was positive, where people fed it or looked after it or something? That's something we'll probably never know."

Emus are social animals and often live in family groups, however older males do tend to live alone.

Unusually for the animal kingdom, it is the fathers that incubate and then raise their chicks.

As to whether Fred may have lost his family group and was lonely, Mr Jones said this is the most plausible suggestion.

"It sounds like a really strange thing to say, but that's a perfectly possible theory that it somehow lost its group, and people are big and tall like they are," he said.

Mr Jones also speculated that Fred's level of intelligence might explain his behaviour.

"There are two theories, [either] it's a very smart bird, that figured out this is a great way to make a living — 'I could just hang out with the people and they'll protect me' — or the opposite, it's not a very smart bird in any way at all, it might be mentally deficient in a serious way, and so it's just there because it's not very smart," he said.

"But I'd be inclined to think it's the other direction, that it's seen an opportunity here and said 'I can probably benefit from this if I hang around with these people'."