Killer whales sue for enslavement

Five killer whales are suing Sea World over their "enslavement" at the marine park.

The mammals have been named as plaintiffs in the case taken by PETA, which argues that whales deserve the same constitutional protection from slavery as humans.

Sea World’s legal team has said the case is "a waste of time and resources".

This is the first time that a US court has had to consider whether constitutional rights apply to animals.