A few choice facts about the common garden snail, courtesy of the kindergartners at Oak Grove Elementary School in Graton:

; A snail can never leave its shell completely, because its heart and lungs are inside.

; Snails breathe through air holes on the underside of their bodies, not through their mouths, and have tongue-like structures with hundreds of teeth.

; Early snails were around before the dinosaurs. "They're really ancient," 5-year-old Max Hall said.

; Garden snails have both male and female reproductive organs — or, as William Benelli, 6, puts it, "They're boys and girls at the same time."

"When I found out," said classmate, Maddie Castro, "I was like, 'Can they marry theirself then?'"

The answer? No. It still takes two to make a family.

Weeks of such close-up inquiry into the slimy creatures — including putting them to the test on snail-sized obstacle courses with a variety of handmade apparatuses — turns out to reveal a whole range of interesting facts about the ubiquitous, and, for some, pesky, being.

The snail unit, a staple of Oak Grove's kindergarten curriculum for the last two decades, is such a consistent hit, it brings graduates back year-after-year to see what successive classes are doing, said teacher Gabi Shader, one of two whose kindergarten classrooms are devoted to snails at this time each year.

At its center, are what different classes call their "snail circus," "snail playground," or "snail city" — table-top play areas where the kids build swings and tightropes, climbing structures, tubes, snail wagons, a "snailboat" pond and all manner of playthings to see just what snails can do, which is "almost anything," said Jonah Caron, 6.

Perch atop the pointy ends of bundled toothpicks or pencils? No problem.

Crawl across a sheet of sandpaper? Piece of cake.

Pull a miniature plastic wagon. Sure. "It just takes a long time, because they're slow," Caron said.

A conference that teacher Terese Drury attended more than 20 years ago inspired her to develop the snail-based curriculum for Oak Grove kindergartners. It integrates math, science, art and language arts around a common mollusk the kids can collect right from the school garden.

"Snails are so incredibly wonderful because they are so patient with all the children and the handling," Shader said.

In the three or so weeks before returning the snails to the wild, the kids read snail books, write snail stories, do snail math and create all kinds of snail art from paint and paper, yarn and ceramics.

Their intensive study wreaks havoc, however, when parents later want to dispense with the snails in their own gardens at home, so affectionately do the kids eventually view them, Shader said.

It seems a small price to pay for a roomful of 5- and 6-year-olds conversant on all things snail — the faint stripes on their muscular stomach feet, the protective and lubricating function of the slime they produce, the tiny black eyes at the ends of two retractable tentacles.

"We're pretty much snail experts," Caron said.

(You can reach Staff Writer Mary Callahan at 521-5249 or mary.callahan@pressdemocrat.com.)