YouTube star Milo the sea otter has died of cancer at the Vancouver Aquarium. Milo was 12 years old. Milo has been seen by more than 16 million people on YouTube holding hands with his female companion. The sea otter had been diagnosed with lymphoma and was being treated at the aquarium. Milo became a YouTube favorite when he was filmed four years ago floating on his back and holding paws with his female companion.