US customs agents found the skull of a young dolphin in an unaccompanied bag at Detroit airport, prompting a federal law enforcement investigation

• CBP agents found a dolphin skull inside luggage at the Detroit Metropolitan Airport.
• Airport employees found the skull during a routine scan of someone's luggage, the agency said.

US customs agents on Friday found a dolphin skull inside someone's luggage at the Detroit Metropolitan Airport —prompting an investigation.

Authorities found the dolphin skull during a routing X-ray scan of the baggage which had been inadvertently separated from its owner before arriving in the United States, US Customs and Border Patrol said in a statement.

"Upon further examination by CBP and US Fish and Wildlife Service officials, it was determined the skull was from a young dolphin," the agency said in the statement.

CBP official Robert Larkin said in a statement that the possession of "wildlife items, especially those of protected animals is prohibited."

"We take wildlife smuggling seriously and work closely with our federal partners at the US Fish and Wildlife Service to protect wildlife and their habitats," Larkin said.

The agency said it handed the skull over to the US Fish and Wildlife Service's law enforcement arm for further investigation.

Dolphins are protected under the Marine Mammal Protection Act, which was designed to keep marine mammal populations from declining.

Certain fish and wildlife, such as wild birds, mammals, reptiles and fish, among others, have import and export restrictions, according to US customs; also any animal par — including skins, tusks, bone, feathers and eggs — are also subject to restrictions, the agency said.

Officials for the CBP and the Fish and Wildlife Service did not immediately respond to Insider's request for comment.