Jonathan, 186, is the oldest giant tortoise - and probably the oldest land animal - to roam the Earth. And there's a good chance that our reptilian elder is gay.

Jonathan has been living a life of leisure since he moved from the Seychelles to the remote British territory of St Helena in 1882. Over a century later in 1991, when he was 160, he met Frederica, another elderly tortoise, and proceeded to woo her for almost three decades.

However in 26 years, they never managed to procreate. The sweethearts mating sessions every Sunday - Jonathan is a creature of habit, apparently - were to no avail.

Until very recently, their keepers at Plantation House couldn't explain why. But it turns out there's a perfectly logical explanation: His beloved Frederica is actually a… Frederic.

The tortoise's belated gender reveal happened by accident. Frederika suffered from lesions in her shell that needed repairs. Closer examination by the island's vet revealed that Jonathan's girlfriend was in fact another male, reported the Times.

The discovery is timely, as the tiny island of 4,255 in the south Atlantic is debating whether to allow same-sex marriage. A bill was introduced earlier in 2017, which allowed gay couples to marry, but was then withdrawn because of its poor reception among locals.

Perhaps Jonathan and Frederic's love will shine a new light on the legality of same-sex union?

Jonathan has been a resident of St Helena since his arrival in 1882, when he was a young lad believed to be about 50 years old. It seems that determining Jonathan's age is as difficult as determining Frederic's rightful gender.

There is no record of his hatching. In 2015, St Helena vet, Joe Hollins said: "We have a record that he was landed in 1882 fully grown. We are told that fully grown is at least 50 years of age, and so this is how we extrapolate back to a hatching date of 1832."

However, it is clear he lived well beyond the life expectancy of a giant tortoise, which is 150. His eyes are dimmed by cataracts and his sense of smell is gone, however his passion, it would appear, remains undimmed.

The science of determining a tortoise's gender

One can determine the sex of a tortoise by examining the shell, tail and claw sizes of a specimen as well as species-specific clues. For instance, a male tortoise's tail is usually much longer than a female's. But Frederic's case shows that it's very easy to get it wrong.

In August 2017, a Phd student from Queensland, Donald McKnight claimed sex toys - vibrators in particular - had a 100% accuracy rate in determining a turtle's sex. McKnight told ABC that previous research showed vibrators could collect sperm from male turtle, making it easy to make out male ones from female ones.

By placing the device on turtles, the researcher was able to provoke a sexual reaction in the turtles: "What you're looking for is for the the male to reveal himself and flash you — basically."

The research was done in Oklahoma in the United States on a wild population of western chicken turtles. It was published in the journal Acta Herpetologica. The method was not yet tested on tortoise species.

Jonathan the tortoise
Jonathan doesn't seem to mind that Frederica was actually a Frederic all along Wikimedia Commons/David Stanley