National Tabby Day

In medieval Baghdad, a quarter called Al-Attabiya made a prized striped silk taffeta known as attabi. The district was said to be named for an Umayyad prince, Attab, though that detail comes down as tradition rather than record.

The cloth traveled west, and so did its name. It passed into Medieval Latin as attabi and into French as tabis, a rich watered silk. English borrowed the word in the early 1600s, still meaning the fabric and nothing about cats.

Then the metaphor took hold. A striped, shimmering cat looked like a bolt of striped, shimmering cloth, and by the 1690s English speakers were calling such an animal a tabby cat. The fabric faded from everyday speech, but the cat kept the name.

Science eventually explained what the legends could not. In 2012, a team writing in the journal Science pinned down a gene, Taqpep, as the switch between the thin mackerel stripes and the wide classic swirls. Every classic tabby they tested carried the mutation in both gene copies.

That work also explained the day's deepest secret: a separate gene decides whether the pattern shows at all. The tabby look is the default for cats, and the modern observance, whoever first set it on April 30, is really a celebration of that default written into nearly every cat alive.