She owns all the swans and dolphins that swim in UK waters.

As early as the 12th century, the British monarchy laid claim to "all mute swans" in the country, according to the official royal family website. Back then, the birds were considered a delicacy. 

Today, the Queen doesn't eat those swans, but she technically still owns them. Every year, the Queen's Swan Marker (actual job title) leads a multi-day census called the Swan Upping to count the birds and check up on their health.

Plus, thanks to 1324 statute, the queen can also claim ownership of all "fishes royal" — that means any sturgeon, dolphins, whales, and porpoises that reside in the waters around the UK.