(KRON) - California residents submitted photographs and videos to Nexstar's KRON this week of mysterious objects falling on their neighborhoods.
Morgan Hill resident Gina Watson shot images of strange, white webby objects that fell "from my house all the way to work," she said.
John E. Banks, an environmental sciences professor at California State University Monterey Bay, said the objects are likely silky webs created by spiders that are ballooning.
"No one has definitively figured out what they are, but they appear to be spider silk," Banks told KRON.
Spiders spin out long lines of silk in a phenomenon called ballooning. Several spider species use ballooning to blow in the breeze from one habitat to another, Banks said. A spider will weave its own parachute, or "balloon," and drift through the sky with help from the wind, he explained.
The New York Times reported that spider silk is so thin and light that air is like a "thick fluid" in comparison.
"The effect of gravity is easily counteracted. In a breeze, the flowing air carries the silk threads along with it, as the spider rides beneath," the report stated.
Dr. Fredrick Larabee, a professor of biological sciences at San Jose State University, said the ballooning spiders could be baby spiders, also known as spiderlings.
"After they hatch, baby spiders release strands of silk that get caught by the wind and carry them to new homes. That way they can find food and homes without competing with their siblings," Larabee told KRON.
"I haven’t been able to catch a spider in any of these yet to figure out what species is ballooning right now, but many spiders are hatching this time of year," Larabee said.
Spiders use ballooning for many reasons, some of which are still unknown to researchers. Researchers do know that ballooning helps protect spider populations from dying out when conditions change and food becomes less plentiful.
"Evolutionarily, it is a very smart strategy for spiders that live in an unstable environment, like farmland," Banks said.
Shifts in the atmosphere's electric fields are also suspected to be factors for when spiders weave balloons, he added.
Banks said there are 45,000 to 50,000 species of spiders on the planet, and they play an important role in keeping an ecological balance.
