Down on the farm

There was a Texan farmer here in Australia for a vacation. Randy, up and goes to see an Aussie farm.  There he meets Glen, an Aussie farmer and the two farmers get to talking.  With pride the Aussie shows off his big wheat field and the Texan says, 'Oh yeah.  We have wheat fields that are at least twice as large as that.'
Then they walk around the station a little, and Glen shows off his herd of cattle. Randy immediately says, 'We have longhorns that are at least twice as large as your little cows.'
Feeling a little insulted the Aussie farmer takes the Texan to see his best and tallest trees. Walking through the thick forest the Texan looks around a little and states ‘In Texas the trees grow twice as big as these twigs’.
The two wonder on, the conversation has, meanwhile, almost died when the Texan sees a big mob of kangaroos hopping through the field. Taken aback he asks, '...And what are those?'
The Aussie replies with an incredulous look, 'Don't you have any grasshoppers in Texas.'