In 1888 a curious white dolphin appeared in the strait between New Zealand’s north and south islands. “Pelorus Jack” would guide steamers through the dangerous French Pass, known for its rocks and strong currents, swimming alongside each ship for up to 20 minutes.

No one knows where Jack came from or what led him to do this. He appears to have been a Risso’s Dolphin, Grampus griseus, uncommon in those waters, but he led ships through the strait for 24 years, and not a single shipwreck occurred in that time. He disappeared in 1912, as mysteriously as he’d come.

See also Everybody Wins.