Worldwide, the appetite for meat is steadily growing. But it's increasingly clear that global meat consumption is causing huge environmental problems, and today's livestock industry may be unsustainable. In the future, we may need to direct our appetites at animals that can be farmed and harvested without profound environmental damage.
In fact, if we pick our proteins carefully--by eating, say, invasive animal species--our carnivory might even be good for the planet. Here is a guide to some of the vermin, unwanted immigrants, and other creatures you can find on the other end of a more environmentally enlightened fork.
A high-ranking Indian official has recommended that citizens start eating rats to avoid rising food prices and safeguard the nation's stocks of grain, commonly eaten by the rodents. Urban rats could carry disease but, says Joe Roman, a conservation biologist at the University of Vermont, "If you get over the squeamish factor, and you know where these rats have been, sure, it could work. It's a great source of protein."
In fact, as global meat prices have soared, rat has become more popular in parts of Southeast Asia. This increase in popularity has, in turn, driven up the price of rat meat four-fold.
Overfishing has reduced populations of large, predatory fish, allowing jellyfish populations to bloom. In some formerly biologically diverse areas of ocean, jellyfish biomass now exceeds that of fish. This shift is likely to continue: Climate change and pollution are changing the ocean chemistry, creating conditions favorable to jellyfish.
What's more, jellyfish eat fish eggs, so once they become dominant in a marine ecosystem, they tend to be there for good. "Jellyfish will be the seafood of the future not because that's what we want to eat, but because that's the only option," says Jennifer Jacquet, a doctoral student at the University of British Columbia's Fisheries Centre.
The Japanese have learned to make the flavorless, nutritionally sparse creatures more palatable; consumers can find jellyfish ice cream, jellyfish biscuits, rum-soaked jellyfish, and even wasabi-flavored jellyfish sold in vending machines.
The nutria, a water-loving rodent native to Argentina, was first brought to the U.S. to be farmed for its fur. When demand for their pelts died off, the herbivorous rodents flourished, chomping their way through the marshes and wetlands of the southeast U.S.
The U.S. Geological Survey estimates that nutria have damaged more than 100,000 acres of wetlands, and the Louisiana Department of Wildlife and Fisheries has offered a $4-per-tail bounty for the creatures. The department has actively promoted the consumption of nutria meat, and runs a website featuring recipes for nutria chili, sausage, gumbo, and more.
Pigeons aren't native to North America; colonists brought them here for food. "There's no substantive difference between the squab you order in a French restaurant and the pigeons you see on the street," says Courtney Humphries, author of Superdove: How the Pigeon Took Manhattan ... And the World.
But it's not necessarily safe to nab a bird off your urban balcony; city pigeons are high in toxins, including lead. Rural dwellers can probably eat wild pigeons, and pigeon-hungry urbanites can raise their own birds. "You could have a steady source of meat just by keeping a few pigeons in the coop," Humphries says. "It's a pretty nice-tasting bird."
Grey squirrels are an invasive species in the U.K., where they threaten the survival of the beloved native red squirrels. Some British restaurants have put grey squirrel dishes on their menus, and one company even sells grey squirrel pate--accented with hazelnuts and Frangelico--and donates the proceeds to a red squirrel conservation group.
The meat is low-fat and sustainable, but it's not exactly popular. More than half the grey squirrel population is infected with the squirrelpox virus, says Richard Wales, the project officer at the conservation group Red Squirrels in South Scotland. The virus is harmless to humans, he says, but "it hardly makes the eating of them an attractive proposition for the average U.K. family."
Insects are nothing if not abundant; according to some estimates, there are as many as 10 quintillion insects alive at any one moment. Bugs are not only high in protein, vitamins, and minerals, but are also more efficient than livestock at converting their food into edible tissue--a veritable food super-factory. Humans already eat more than 1,400 species of insects, and bug-farming is a growing industry in Southeast Asia.
In the U.S., of course, "it's not easy for many people to pop bugs into their mouths when they've been conditioned over a lifetime to despise them," says Patrick Durst, a senior forestry officer at the U.N. Food and Agriculture Organization.
But, he says, "there's really no reason that insect protein has to look like a bug. Insects could readily be used as ingredients in a multitude of foods, or reconstituted in much the same way that fish sticks and chicken patties are currently."
The digestive processes of cows and sheep produce huge quantities of methane, a potent greenhouse gas. Kangaroos, on the other hand, emit little methane. Researchers at the Australian Wildlife Service published a 2008 paper discussing what would happen if Australians ate less livestock and more marsupial meat.
The scientists suggest removing 7 million cattle and 36 million sheep from the country's livestock industry and, over the course of 13 years, bringing the nation's kangaroo population from 34 million to 175 million. This swap would produce the same amount of meat while decreasing Australia's total annual greenhouse gas emissions by 3 percent.