Robert F. Kennedy Jr sawed the head off a dead whale and brought it home strapped to the roof of his car, his daughter claimed.

Kick Kennedy said in a rediscovered interview from 2012, her father, who enjoys studying animal skulls, used a chainsaw to cut off the creature’s head when it was up on Squaw Island in Hyannis Port.

Mr Kennedy is said to have used a bungee cord to tie the enormous skull to the roof of their family minivan before driving home for five hours to New York.

“Every time we accelerated on the highway, whale juice would pour into the windows of the car, and it was the rankest thing on the planet,” Ms Kennedy told Town & Country magazine in 2012.

“We all had plastic bags over our heads with mouth holes cut out, and people on the highway were giving us the finger, but that was just normal day-to-day stuff for us.”

It is the latest bizarre animal story involving the former independent presidential candidate, who dropped out of the presidential race to endorse Donald Trump last week. In recent months, he admitted to dumping a dead bear cub in New York as a prank and has been accused of eating a dog.

The Centre for Biological Diversity Action Fund, an environmental group, suggested that Mr Kennedy may have broken several laws and called for an investigation into the 70-year-old.

It is illegal to possess trophies of several whale species in the Atlantic Ocean under the Marine Mammal Protection Act and the Endangered Species Act, the group claimed, according to the Washington Post.

“Furthermore, Mr Kennedy’s apparent transport of the marine mammal skull from Massachusetts to New York, and therefore across state lines, also represented a felony violation of the Lacey Act, one of the earliest wildlife conservation laws enacted by the United States,” it added.

Mr Kennedy, the nephew of former president John F. Kennedy. did not respond to requests for comment when approached by the Washington Post.

In August, he admitted dumping a dead bear cub in Central Park, New York City, solving a mystery that had puzzled locals for the last decade.

He said the prank, which involved leaving a bicycle at the scene to make it look like an accident, was meant to be “amusing”. A picture shows him posing in the back of the car with the cub, his fingers in its bloody mouth.

In July, Vanity Fair reported that Mr Kennedy had eaten a dog on a trip to Korea, and published a photo of him posing with a barbecued carcass.

The then-presidential candidate insisted that he had actually eaten a goat and that the picture had been taken in South America.