What are the Laws Regarding Animal Rights in the United States?
As of November 2019, it is now a federal crime to commit certain acts of animal cruelty. The new law is the Preventing Animal Cruelty and Torture (PACT) Act. Penalties include up to 7 years in federal prison. Most states also have laws prohibiting these acts. See Animal Rights in California.
What are the laws regarding endangered species?
The Endangered Species Act (what a surprise with the name) requires the federal government to research and list the endangered species of plants and animals and provide regulations to protect these species from extinction. The ESA is regulated by the United States Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration (NOAA) (which includes the National Marine Fisheries Service, or NMFS). NOAA handles marine species, and the FWS has responsibility over freshwater fish and all other species.
Is it illegal to import elephant or lion parts into the U.S.?
Update March 2018: The Trump administration now says it will allow importation of African sport-hunted elephant trophies (as well as trophies of lions and certain antelopes) on a case-by-case basis.
Background: In 2014, the U.S. Fish and Wildlife Service made it illegal to import any sport-hunted elephant parts (aka “trophies,” tusks, or ivory) from Zimbabwe and Zambia. But it remained legal to import elephant parts from other African countries that have been legally hunted for sport (up to 2 allowed per year per hunter).
The Fish and Wildlife Service also allows the importation of African elephant parts for scientific or law enforcement purposes.
As for importing elephant parts for commercial purposes (for example, to sell it), this is banned completely.
Certain Antique African elephant parts for noncommercial purposes may be imported.
As for Asian elephant parts, these may only be imported if they are at least 100 years old.
In general, the Endangered Species Act requires that in order to allow the importation of trophies of endangered animals, it must be demonstrated that hunting enhances survival of those animals in the wild, for example, that the money paid by hunters to kill an animal will be reinvested in conservation and the local community.
See more on this at the U.S. Fish and Wildlife Service
City and state laws
States and cities have many more laws regarding animal rights and welfare. Some cities, including New York City and Los Angeles, have banned foie gras. And see Animal Rights in California.