Throwing rice at a newly married couple has been a tradition for thousands of years, possibly going back as far as the ancient Assyrians and Egyptians. The idea is to give the newlyweds good luck, fertility, and abundance using this symbol of a good crop. More recently, wedding meddlers have cautioned against throwing rice because it can kill birds who swoop down and eat it after the human revelers have left for the reception. The rice grains, absorbent as they are, supposedly start sucking up water in the birds’ moist innards and cause them to violently burst.
It's not clear where this idea came from, but it hit the peak of its popularity in the late 1980s when the Connecticut state legislature discussed a bill outlawing the tossing of rice at weddings and advice columnist Ann Landers printed a letter about the practice.
Wherever it came from, you can quit worrying about the birds.
The reality is that rice poses no harm to them. Wild birds eat uncooked rice all the time with no ill effects. Many types of waterfowl, shorebirds, and migratory birds depend on flooded rice fields to maintain fat in the winter. A bird called the bobolink eats enough rice that it's considered a pest by farmers and has earned the nickname "ricebird."
Besides the numerous birds that regularly eat rice and don’t explode, another thing to consider is the fact that dried rice grains are pretty slow to absorb liquid unless it's boiling, which birds’ stomachs certainly aren’t. Their internal temperatures generally range from 100.4 to 107.6 degrees F, well below the boiling point of any liquid that would be inside them. Even if birds did have boiling guts, any uncooked rice they consumed would be broken down well enough by their crops and gizzards that the pieces shouldn’t cause any problems as they expand.
Mythbusters or Gutbusters?
Now, these explanations of why rice is not bad for birds rely on two things: what we know about birds, and what we know about rice. We understand both pretty well, but wouldn’t a good experiment go a long way toward putting the myth to rest?
That’s what James Krupa’s students at the University of Kentucky thought. During the spring 2002 semester, Krupa and his 600 biology students decided to test the exploding bird myth with a series of experiments. They looked at the expansion of different types of grains, considered the strength of birds’ digestive organs, and tested an all-rice diet out on the professor’s pet birds.
The first notable thing they found was that white rice increased in volume by 33% when soaked, while bird seed expanded by 40%. If rice was going to make birds explode, then we’d already doomed them anyway with birdfeeders full of seed. The most significant expansion was seen in white and brown instant rice, which expanded 2.4 to 2.7 times its original volume when soaked. Of course, instant rice is usually more expensive than the regular stuff and comes in smaller quantities, so it's not very likely that anyone is throwing around opened packages of Uncle Ben’s at weddings.
But what if they did? To see if instant rice could burst a bird from the inside out, Krupa and his students built model bird crops from very thin plastic and from wet paper bags, and filled them with various grains and water. None of the plastic crops exploded, but a paper bag filled with instant white rice expanded and ruptured in about 15 minutes.
Not satisfied with their bird-gut surrogates, the students begged Krupa to test the rice out on real birds. Krupa felt confident enough that no birds would be harmed based on their previous results, so he agreed to turn the flocks of doves and pigeons he kept at home into guinea pigs. He fed 60 of his birds a diet of nothing but instant rice and water for a day, and monitored them for signs of distress or discomfort. Krupa reported that no birds choked, exploded, or otherwise were injured or died. None of them threw up or even showed any sign that they were in pain; they went through their all-rice day with no problems.
Birds, it seems, have no problem with rice, but this doesn’t mean that it's perfectly safe to throw at weddings. Hard, tubular grains spread out on the sidewalk in front of a church can still create a slipping hazard for another animal: wedding guests. The fear of slip and fall injuries and the lawsuits that go with them have led some wedding venues to ban rice—not for the birds, but to keep themselves out of court.