Only halfway through the biting season, rattlesnakes may be closing in on a record.
Bites were up 48 percent in the spring. From April through June, 184 rattler bites were reported to the state Poison Control System. During that same period last year, there were 124.
"We have a significant increase in cases this year," said Stuart Heard, executive director for Poison Control. He suggests that weather and environment may be a factor.
A wet 2011 winter created good conditions for snake survival; this year's drier-than-average winter may have pushed them to travel farther for food and water.
An average of about 300 rattlesnake bites are reported each year to the California center, most between April and October.
"They deliver a nasty bite, whether it's a baby or adult," naturalist Katie Colbert said.
"And this is the time of year when people and rattlesnakes are most likely to come into contact because they both like to be outdoors now."
Some bite victims are simply in the wrong place outdoors at the wrong time.
A young rattlesnake bit 7-year-old Gianni Thomas on the foot June 3. He was on the back patio of his family's ranch home south of Pittsburg.
The snake, which was less than 16 inches long, sank its fangs into Gianni's right foot and didn't let go until the boy's older brother, William, yanked it away as venom squirted over the patio, said the boys' mother, Tina Thomas.
Gianni's leg swelled up
Fears on display
"It was terrifying," Tina Thomas said. "It's a risk on the ranch and, for that matter, for people who hike on trails in open land. You have to watch out and be careful."
Thomas said her family members see rattlesnakes every year, but they have seen more this year than in recent memory -- at least 20 sightings so far.
On average, fewer than one of the rattlesnake bites in California are fatal each year. Bee stings and dog attacks account for more deaths, but rattlesnake venom can kill humans and dogs; they also can lead to limb amputations.
As much as she admires their survival tactics and their signature rattle that warns unwelcome visitors, Colbert urges people to keep a distance from the only poisonous snake species in the Bay Area.
Few know rattlesnakes better than Colbert does. She works for the East Bay Regional Park District, and from 1998 to 2007, she did a research project in which she tracked 12 wild rattlesnakes at the Sunol-Ohlone Regional Wilderness that had radio transmitters sewed into their bodies.
Fred, Cleo, Lola and the rest of those snakes didn't wander too far from home, reaffirming her view that rattlesnakes are more like cautious homebodies than bite-happy bullies.
"Rattlesnakes are more like us than we think," said Colbert, who uses a captive rattlesnake named Fergie to make points in her nature education classes. "They like to go out in good weather. They get grumpy in hot weather. They want food, shelter, family and to avoid predators, but they will strike out if they feel threatened."
Researchers have found that many rattlesnake bite victims are young men who were drinking alcohol, said Patrick Foy, a spokesman for the state Department of Fish and Game.
Research also found that many victims are bitten in the hand or arm, indicating that the people either intentionally reached for a snake or reached into rocks, weeds or brush without taking precautions, Colbert said.
She recalls a visitor to Del Valle Regional Park near Livermore who attempted to demonstrate to his child the best way to pick up a rattlesnake. The man ended up being rushed to the hospital for treatment of a bite.
In May at the same park, a 29-year-old man was bitten by a swimming baby rattlesnake that he picked up in the reservoir. He thought it was dead. The man required antivenin treatment at a hospital.
The best advice, naturalists and public health experts say, is for people to leave rattlesnakes be unless it's in a place where it can't be avoided.
Back at the Sunol Regional Wilderness visitor center, Colbert recalls how her radio tracking over nine years honed her rattlesnake fascination.
She saw snakes swim across a creek and hang out together. She saw a snake curl up and wait for hours next to a barely recognizable path in the grass used by rodents.
While she knows more about rattlesnakes than most people do, Colbert said she knows not to feel confident because their behavior is unpredictable.
"They can surprise you," she said.
Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff.
To avoid bites:
Avoid rattlesnakes. Back away, and give it the right of way.
Watch your step; wear long pants and boots when in snake country.
Look for hidden snakes before picking up wood or sticks.
In tall grass, carry a stick to scan the ground and scare them away.
Stay at least six feet away. Keep animals under control.
Don't assume a snake isn't poisonous if it doesn't rattle. Rattlers sometimes strike silently.
Rattlers swim. Don't pick up any that look like a stick or a branch in the water.
Hike with a buddy if possible, and carry a cellphone
Get everyone in your group away from the snake so it doesn't bite again.
Seek emergency medical help. Decide if the quickest way to get help is to walk the victim out or to leave them behind and summon help to carry them out.
Remove jewelry or tight clothing from the affected limb.
Keep the victim as calm as possible.
Don't apply a tourniquet or try to suck out the venom.
Source: U.S. Department of Forestry, California Department of Fish and Game, California Poison Control System