Even if you read educational materials at zoos and donate money to conservation organizations, your eating habits may be unintentionally undermining the threatened species you care about.
A recent study of shark fin soup from restaurants in 14 states revealed a variety of endangered, vulnerable and near-threatened shark species swimming in the broth. The finding raised questions about how many other at-risk creatures are readily available on restaurant menus.
It may be easier to order a troubled entrée than you think, experts say, especially if you eat fish and seafood.
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"Seafood, fish and invertebrates are the last wild food that we eat as animal protein" and can buy in stores or restaurants, said biologist Susan Lieberman, director of international policy for the Pew Environment Group in Washington, D.C. "It doesn't mean it's safe for a species just because it's on a menu."
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There are a variety of laws that regulate the trade of animals across state and national lines, Lieberman said. If a species is listed under the United States Endangered Species Act or the Marine Mammal Protection Act, for example, it cannot be imported into the country for any reason, including for use as food. Even if a species is not listed federally, some states may regulate its sale.
Likewise, if a species is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), which categorizes it as threatened with extinction, it is illegal to import that species for commercial use.
If the species is on Appendix II of CITES and is considered at risk of becoming threatened with extinction, on the other hand, import is allowed, though the process requires permits and other regulatory hoops.
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The International Union for Conservation of Nature also maintains a Red List that ranks species based on how much trouble they're in, but it's still legal to import and sell species given an IUCN listing of threatened or endangered if they are not listed by CITES or the U.S. government.
Meanwhile, only an estimated 10 percent of 30,000 known fish species have even been evaluated by the IUCN, said Sheila Bowman, senior outreach manager of the Monterey Bay Aquarium Seafood Watch program. Sometimes, species of concern that are proposed for listing get refused protection by the U.S. government.
That leaves it up to diners to be informed enough to make their own decisions.
"We're not telling people they shouldn't eat stuff, but they should be aware when they go to markets or restaurants, they should know what they're eating and where it came from, and they should ask questions," Lieberman said. "Every bowl of soup adds up."
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AFRICAN LIONS
"Every summer, some chef somewhere comes up with the idea of serving lion tacos or lion burgers," said zoologist Teresa Telecky, director of wildlife at Human Society International in Washington, D.C.
In the last few years, lion meat has shown up on menus from California to Kansas. And even though lion burgers often spark outrage among the public, it's not illegal for chefs to buy, cook, or sell the meat.
For now, lions are listed as vulnerable by the IUCN -- a step below endangered and two steps below critically endangered. That status hasn't been reviewed in years, Telecky said, even though lion numbers have dropped by 50 percent in the last two or three decades. The top predators now occupy just 25 percent of their original habitat.
"If a restaurant owner wakes up one day and says, 'I know how to boost sales,'" Telecky said, he can "legally order lion meat from any exotic meat dealer."
BLUEFIN TUNA
Despite dramatic declines in abundance and an endangered listing on the IUCN Red List, the U.S. government decided not to protect Bluefin tuna after considering it for listing under the Endangered Species Act last year.
That means that, for now, the fish will remain on many sushi menus, where it is also called toro, hon maguro, or kuromaguro.
Bluefin tuna -- which live and migrate throughout the Mediterranean Sea and the Pacific, Atlantic, and Southern Oceans -- are slow to mature, according to the Monterey Bay Aquarium's Seafood Watch program. And fisheries often catch the fish before they've reproduced.
Based on an analysis by Iccat, an inter-governmental fishery organization focused on the conservation of tunas, the New York Times reported last year that numbers of bluefin old enough to reproduce dropped more than 70 percent from 1970 to the mid-90s in the western Atlantic and by 80 percent between 1970 and 1992 in the eastern Atlantic. Since then, numbers seem to have mostly stabilized.
"For bluefin tuna, the problem is overfishing," Lieberman said. "All of that is because there's a market for it."
CAVIAR FROM STURGEON (BELUGA CAVIAR)
Sturgeon fish live a long time, grow slowly, and reproduce late in life. The only way to get eggs out of the fish is to kill egg-filled females, which has a reverberating effect on the species involved: Neither the eggs nor a productive female can go on living.
Eighty-five percent of sturgeon species around the world are at risk of extinction, according to an IUCN report released in 2010. That makes them one of the most threatened groups of animals on the Red List.
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As alternatives, the Monterey Bay Seafood Watch program suggests U.S. farmed sturgeon and its roe, which is often called beluga caviar. But the program suggests avoiding the wild varieties.
CHILEAN SEABASS
Technically known as Patagonian toothfish, Chliean seabass may come baked or pan-seared. But the white, flaky, deepsea delicacy is suffering from overfishing.
Like bluefin tuna, Chilean seabass grow slowly and live for several decades, but their reproductive rates are low, making it hard for them to sustain populations in the face of fishing pressures.
The Marine Stewardship Council, an independent organization that has developed sustainability standards and labels, has validated at least one population of Chilean seabass. But a DNA study last year found that even labeled fish often come from populations that are not managed sustainably.
The Monterey Bay Aquarium Seafood Watch program suggests avoiding Chilean seabass altogether, pointing out that the fish is also high in mercury and that the methods used to catch it often snare albatross and other seabirds.
TURTLES
Many species of turtles and tortoises, both freshwater and sea-dwelling, are listed as endangered or critically endangered around the world. But that doesn't stop illegal turtle eggs and meat from showing up in Asian food stores and on menus in the southern U.S. and in tropical regions.
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A Chinese appetite for turtles is one of the animal's greatest threats worldwide, according to a report released last year by the Turtle Conservation Coalition, a consortium that included the IUCN. Every year, China imports millions of turtles from Asia, Africa, and North America for use in food, medicinal products, or sometimes as pets. And 17 of the world's 25 most endangered turtles live in Asia.
Asian restaurants and markets are one of the most common places to find endangered turtle meat in the U.S. But even the Food Network and Cooks.com offer turtle soup recipes.
And while some turtle populations may be healthy, it's often impossible to know where the turtle you're eating came from.
"Millions of animals are being taken from the wild every day to go into these various purposes, one of which is exotic foods," Telecky said. "We always urge people to be aware of the origins of what it is they're eating."