Known as a "leaper," the character must serve his pirate clan until his 21st birthday, not just his 21st year.
He'd be 84 years old by the time he celebrated that many birthdays.
Why? As anyone born on Feb. 29 can attest, leap-year birthdays come only once every four years.
First used in Roman times, a leap day is added to ensure the Gregorian calendar stays in line with the Earth's orbit around the sun. It takes about 365 ¼ days for Earth to travel one full rotation.
So every four years an extra day is added to the month of February.
That pesky quarter-day every year does add up, though. Because of the disparity we have to leap a leap year every now and then. Not to worry, the last skipped leap year was in 1900 and the next time leap year is scheduled to be skipped is 2100.
The Hebrew calendar, known as a lunar calendar, adds an extra month every four years.
This means that if you were born on Feb. 29, 1960, you would be 52 years old, but you'll only be celebrating your 13th birthday on Wednesday.
More Life Headlines
Answers to homeschooling questions Today in history 15 trails you can enjoy in a wheelchair Wait wait — can you say that on air? There’s an internal debate on cursing at NPR Breasts made for babies, so chill out When it comes to sports, foster healthy competition for kids This week’s best-sellers from Publishers Weekly It’s prime time for stargazing
Our to-do list full of ideas for your weekend
Our new comment system is not supported in IE 7. Please upgrade your browser here.