Sales of giraffe parts are booming across the U.S. -- and it's totally legal.

An undercover investigation by the Humane Society of the United States and Humane Society International found giraffe parts and products being sold online and in stores in at least 52 locations nationwide.

The organization said an investigator went undercover at 21 sites in California, Florida, Maryland, North Carolina, New York, Oklahoma, Tennessee and Texas.

Among the findings in the Humane Society's report:

-- The most commonly found giraffe products were western boots made from giraffe leather and specialty knives made from giraffe bones.

-- Other products included giraffe taxidermy trophies, giraffe hide pillows and rugs, giraffe skin bible covers and furniture and giraffe bone carvings.

-- Investigators said some sellers falsely reported giraffes as dangerous and told investigators that giraffes must be killed in defense of villages in Africa. The sellers told investigators that the parts they sell are a byproduct of defensive killing.

-- Some sellers of giraffe products and parts have criminal records for animal-related crimes, including trafficking of rhino horns.

-- American trophy hunters supply the U.S. market with giraffe trophies and parts.

In a release, Kitty Block, acting president and CEO of the Humane Society of the U.S. and president of Humane Society International, said:

"Purchasing giraffe parts puts the entire species at risk. The giraffe is going quietly extinct. With the wild population at just under 100,000, there is now fewer than one third the number of giraffes in Africa than elephants."

The Humane Society's investigation found giraffe products being sold for up to $8,000, including full taxidermy pieces, skulls, giraffe hair bracelets and feet.

The organization reported that more than one giraffe per day is being imported into the U.S. by American trophy hunters. It also said threats like these add to the decline of the species by 40 percent in the past 30 years.

It is not illegal in the U.S. to trade in giraffe parts. But in 2017, the Humane Society and conservation partners petitioned the U.S. Fish and Wildlife Service to list giraffes as "endangered" under the Endangered Species Act.

An "endangered" listing would restrict the importation, exportation and sales of giraffe parts in the country.

The petition report from 2017 said about 40,000 giraffe parts and products were imported in the U.S. from 2006 to 2015.