Why spiders are coming out in their thousands during flooding

A phenomenon that has seen thousands of tiny spiders crawling to higher ground to escape floodwaters across NSW can likely be traced back to a single instinct.

They’re trying to survive.

Spiders and insects quietly living in the grass or inside burrows were most likely left temporarily homeless when floodwaters inundated their habitat.

Thousands of spiders have been seen escaping flooding in NSW. Source: Facebook/Matt Lovenfosse
Thousands of spiders have been seen escaping flooding in NSW. Source: Facebook/Matt Lovenfosse

University of Queensland’s Associate Professor David Merritt told Yahoo News Australia that spiders probably don’t have much choice when they end up in people’s homes as they search for higher ground.

The spiders' “reflex escape reaction” would be motivated by an understanding that they don’t do well in water, forcing them out of hiding and into vulnerable positions.

While Associate Professor Merritt acknowledges many in the community will be unnerved by the influx of creepy-crawlies, he has some simple advice for dealing with the situation.

“I’d say just leave them alone and let nature take its course,” he said.

“I would hate to think anyone would spray insecticide on them or that sort of thing.

"They’ve only come into houses and human made structures because they’ve been forced to, so give them a bit of time and they’ll disperse back into their natural environment.”

Fleeing spiders a sign of a healthy ecosystem

The spiders and other insects that have been washed up are actually a sign of a healthy ecosystem, Assoc Prof Merritt believes.

“That there's such a good diversity out there is an encouraging thing,” he said.

“If there was no wildlife disturbed at all by a flood, then I’d be going that’s a bit of a worry.”

Spiders will usually disperse once floodwaters dissipate. Source: Getty
Spiders will usually disperse once floodwaters dissipate. Source: Getty

Having evolved with floods, in most cases any insects or spiders fleeing the waters will be able to handle the situation themselves, and the death toll will be much less than experienced during bushfires.

In some cases insects can survive for days underwater, as the tiny holes that allow air into the body called spiracles are water resistant.

Snake rescue numbers down despite flooding

Spiders and insects aren’t the only ones who make unscheduled appearances when it floods. Snakes and other reptiles are also driven out of their homes by rising water levels.

Despite an expected influx, snake catchers spoken to by Yahoo News Australia have reported lower than usual call-outs during the storms.

Snakes in the City and Central Coast Snake Catchers which operate in areas inundated by rain, have noted that the colder weather could be keeping all but the most desperate snakes at bay, but believe people may also just not be noticing fleeing snakes because they're staying indoors.

Australian snakes are known to be good swimmers. Source: Getty
Australian snakes are known to be good swimmers. Source: Getty

Animal rescue group WIRES has also recorded a lower than usual call volume during the wild weather, but with flood victims just trying to save themselves and their pets, they are not surprised wildlife isn't an immediate priority.

Their rescuers have mostly been called to assist waterlogged animals, including microbats and possums which have been found sheltering in people’s homes.

Call-outs for animals hit by cars unfortunately haven't slowed down, and the group is asking anyone on the road to be particularly careful of disorientated animals trying to seek higher ground.

As the rain begins to ease, and people take stock of the damage, WIRES expect rescue numbers to increase.

The snake catchers also predict they may receive a few extra calls from people finding snakes in unexpected places once the sun shines again.

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