Let’s just call it donkey-mania.

That four-legged farm animal — the long accepted symbol of the Democratic Party — is everywhere in Boston: marking convention literature, decorating neckties, even imprinted on scented candles at the official online convention store. (No word, though, on whether the candle is donkey-scented.)

And, of course, there’s Swifty, the official Democratic donkey, available for photographs at Boston’s Franklin Park Zoo.

Altogether, not too shabby for an animal that has never been officially adopted as the mascot of the Democratic National Committee.

So how then, did the donkey get hitched to the party’s wagon?

According to the DNC’s official donkey history, the animal’s original connotations weren’t exactly the same ideas — humbleness and courage — that party faithful associate it with currently.

In fact, the donkey was used by opponents of Andrew Jackson’s 1828 presidential bid who labeled the populist a “jackass.”

Although Jackson found use for the animal in his campaign literature, it would be later used again to show his “stubbornness,” notably in the 1837 political cartoon “A Modern Baalim and his Ass.”

“Although in 1837 Jackson was retired, he still thought of himself as the Party’s leader and was shown trying to get the donkey to go where he wanted it to go,” the DNC Web site states.

Despite these early representations, however, political cartoonist Thomas Nast is widely credited with popularizing the beast of burden as the party’s symbol.

Nast’s donkey first appeared in 1870, when he used the animal to represent Democratic press attacking Edwin Stanton, President Abraham Lincoln’s recently deceased secretary of War.

The Harper’s Weekly cartoonist would continue to use the donkey, strengthening its association with the Democratic Party in cartoons suggesting the party’s unease over a potential third term for then-Republican President Ulysses S. Grant.

In an infamous 1874 cartoon, “The Third Term Panic,” Nast would cement the use of both the donkey and the Republican elephant.

According to DNC literature, that cartoon “showed animals representing various issues running away from a donkey wearing a lion’s skin tagged ‘Caesarism.’ The elephant labeled ‘The Republican Vote,’ was about to run into a pit containing inflation, chaos, repudiation, etc.”

Even with lavish attention provided by Nast, though, the donkey faced competition for the hearts of party faithful.

Many of those alternate symbols, such as the rooster or the star, are rooted in the early days of paper balloting.

“When you start having printed ballots, there’s a sense you have to have printed icons for people who don’t read very well,” explained Harry Rubenstein, political history curator for the Smithsonian Institution’s National Museum of American History. “You need some visual icons to let people know they’re voting for the right party.”

Around the turn of the century, when state election commissions took over the production of ballots, many required political parties to provide a symbol.

But, Rubenstein notes, the now widely accepted political symbols weren’t necessarily those selected by the parties themselves.

“You get this symbol and then people begin to adopt it in their own iconography, play off it, and the next thing you know it’s being used over and over again,” Rubenstein said. “Both the elephant and the donkey [were] being driven not by the parties, they [were] being driven by popular cartoonists.”