Image: ANNIE GELLATLY DEVELOPING HABITAT. Irwin is starting up a 2,000-acre koala sancutary near his home in Queensland to show how the cuddly Australian icons can coexist with grazing cattle.

SCIENTIFIC AMERICAN: You have said that you "sincerely and vehemently oppose 'sustainable use,' where people think they can farm crocodiles." Do you feel the same way about wild kangaroos?

STEVE: Absolutely. Yeah, I think it's an absolute disaster that Australia, the government, allowed kangaroo culling. Total disaster.

SA: Some people support moving out some of the cows and sheep and farming kangaroos instead.

STEVE: Oh yeah. I vehemently oppose that. I mean, that is wrong. Australia has already been hit by the bulldozers to grow those cows and sheep. We've got the dams in place, we've got the grazing areas already there. To turn around and say we could farm kangaroos and eat them is an absolute atrocity. Why would you want to eat the Australian icon? Here on the coat of arms is the emu and the kangaroo, the two animals that we want to farm and eat and kill. That's ridiculous. I'm a proud Australian, a very, very proud Australian. I believe that kangaroos and emus need to coexist with grazing areas. That's what has to happen. Anyone who thinks that they can grow kangaroos and get cows off the land is not thinking straight. It won't happen.

What we need to do¿and this is my tack right now, in fact I've gone so far that I've bought 2,000 acres to prove this¿is that we have to protect our graziers [ranchers]. I'm talking globally, not just Australia. We need to protect our graziers, because they are the biggest landowners of Australia and, quite possibly, the world. OK, so we need to help them fight off the old grazing techniques of, you know, clear-cutting, and we need to promote riverine areas and also have trees in and around grazing areas so that kangaroos have shade, cows have shade. The best grass is in and around those trees. You can have koalas, you can have all your bird species, all your insect species and you've got viable flora, and we still get to eat meat.

SA: Have you ever considered becoming a vegetarian?

I went through a big stage of my life where I thought, you know, maybe it would be better to be a vegetarian, so I researched it. In no uncertain terms did I research it. Let's say this represents one cow, which will keep me in food for, let's say, a month. Now that cow needs this much land and food. Well, you can imagine, that cow needs x by x amount of land, and you can grow trees in it. Around that cow, you can have goannas, kangaroos, wallabies. You can have every other single Australian animal in and around that cow. If I was a vegetarian, to feed me for that month, I need this much land, and nothing else can grow there. Herein lies our problem. If we level that much land to grow rice and whatever, then no other animal could live there except for some insect pest species. Which is very unfortunate.

SA: What about this idea of trying to save wildlife by keeping indigenous animals as pets, to increase their value and as a way to keep more of them alive?

STEVE: Yeah, I don't think it's realistic, and I oppose it. Because the animals that need our help the most¿let's take one icon, the koala. No one could look after a koala. They have specialized requirements. One koala needs 300 eucalyptus trees per year, and that's if [the trees are] in good tip. And you need eight different species, so for us to cut for our koalas, we've got a guy on a full-time job.

SA: That's why a sanctuary down in Brisbane has its own plantation¿

STEVE: Yeah, a multimillion-dollar plantation, so you know, the general person can't do that. And I don't believe that that is the answer.