An exotic tortoiseshell necklace, an unusual bone statue, a lovely piece of corral—it's always tempting to bring home a little token of your spring vacation, but what may seem like a simple souvenir is often anything but. Goods made from animal products are a staple in shops around the globe, but bringing them home is generally prohibited.

Wildlife trade is a booming business that includes everything from legal trade of timer and fish to illegal trade of endangered species. TRAFFIC, a joint effort of the World Wildlife Fun and the World Conservation Union that monitors wildlife trade, has estimated global illegal wildlife imports each year are valued in the hundreds of millions of dollars.

Just last week, the Associated Press reported officials in Thailand had seized two tons of elephant tusks that had been shipped from Africa; the pallets had been labeled as cell phone parts. Valued at $3.6 million, the illegal shipment contained 239 African elephant tusks, and the AP reported customs officials believe they were destined to be carved into trinkets and jewelry to be exported or sold to Thailand's tourists.

When most people think of illegal wildlife imports, they think of these large-scale busts, but tourists the world over are responsible for importing animal products illegally.

Under U.S. Fish and Wildlife Service law, it is illegal to import (bring home) any part or product of birds, mammals, reptiles, fish, shellfish, mollusks, or invertebrates without a permit—that includes skin, tusks, bone, feathers, and eggs. Even a seashell from a beach is technically prohibited without a permit.

There are, however, some species that cannot be imported at all, generally because they are endangered or protected species. All sea turtle species are endangered and thus cannot be imported. The FWS recommends avoiding all tortoiseshell products. Elephant ivory is also prohibited, and any items made from whale, walrus, narwhal, and seal teeth or tusks should also be avoided. Furs from cat species, seals, polar bears, and sea otters should also be left behind when you come home.

Trade of animal products is strictly monitored for good reason. Rhinoceros horns are very valuable in wildlife trade, and though some species have rebounded with protection efforts, the Black rhinoceros is still critically endangered with just over 4,000 individuals remaining.

In the Caribbean, coral sales are cause for great concern since some species are rapidly disappearing. In 2009, research out of the University of East Anglia in the U.K. revealed that branched coral no longer exists on 75 percent of coral reefs in the Caribbean. Disease killed nearly all of two branched coral species in the 1970s, and the remaining species suffered during an episode of "bleaching" a decade ago. Bleaching is often caused by warmer water temperatures, which can be linked to climate change. What little coral remains must be fiercely protected, not plucked from the ocean and sold to tourists.

So how can you avoid legal headaches and support species conservation while bringing home something to remember your vacation? Ask a lot of questions. Know how the animal product was sourced for your own peace of mind, and be sure your product comes with CITES certification. CITES is the Convention on International Trade in Endangered Species of Wild Fauna and Flora, and 160 countries have signed the treaty, which supports sustainable wildlife and plant species trade and protects at risk species.

Wherever you're traveling this spring, be sure to question shop owners about animal products, even ones that aren't native to the area where you are traveling. A company may legally import sustainably harvested animal products to manufacture goods, but once you cross an international border with a pair of pretty tortoiseshell earrings, you could find yourself in hot water.

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Cara Smusiak