Valley firm invents

ContraPest, a new fertility control technology for managing animal pest populations, fits into a box with a hole for the critters to get into. (Courtesy of SenseTech)

The latest tool to solve your rat problem has arrived, but it’s not what you expect.

Instead of eliminating rodents using poison or traps, a Phoenix company has developed a more humane method: “Rat birth control.”

SenesTech, Inc. produces ContraPest, a new fertility control technology for managing animal pest populations, primarily Norway and roof rats. It’s a non-toxic, non-lethal liquid dispensed inside tamper-resistant bait stations that causes infertility when ingested.

And it is the only Environmental Protection Agency -registered contraceptive for both male and female rats.

“It’s so good for the environment and just being a kind human,” said Kim Meagher, the founder of Wildhorse Ranch Rescue in Gilbert and an early customer of ContrPest.

“There are a lot of us who don’t want to harm critters, so it’s a really nice way to take care of your rodent population,” she said.

Animal lovers, like Meagher, aren’t interested in killing any. So, when Meagher’s rescue of 27 years developed a roof rat issue, she searched for non-lethal ways to eradicate the infestation. That’s when she found ContraPest.

“It took care of our population in a very humane way very quickly,” she said.

Rats weren’t the only animals Meagher was concerned about.

She had seen a notice posted by Liberty Wildlife, of Phoenix, about how rodenticide poisoning not only kills rats, but also the eagles, hawks, owls, livestock and other wildlife or pets that eat them.

She was thrilled to have found a solution that doesn’t harm any animals and actually works.

“You can poison or kill as many as you want all day long, but they’re still going to have babies,” Meagher said. “You’re not going to get them all. They’re going to reproduce faster than you can exterminate all of them.”

Conventional methods of reducing rat populations simply can’t overcome their rate of reproduction.

If left unchecked, rodents will do what they do best – reproduce rapidly.

Two sexually active rats can be responsible for the birth of up to 15,000 descendants in just one year, according to SenesTech CEO Ken Siegel. If the breeding isn’t stopped, then you can’t get a handle on the population.

“One side of the equation is the birth rate, but the other is the death rate,” Siegel said. “Rats become mature in a very short period of time and then they can have a litter of pups basically every six weeks.

“The pups become mature and they have pups. You see a geometric explosion in the population. If you’re simply relying on death, you can’t kill them fast enough or sustainably enough to offset how fast they reproduce. That’s why birth control is so important.”

ContraPest works because of its two active ingredients. The first ingredient reduces the number of eggs female rats produce, while the second impairs sperm development in male rats.

Although ContraPest targets the reproductive capabilities of rats, it is not a sterilant. For the product to be effective, rats must regularly consume it.

Though Siegel hasn’t seen an effect in other animals, he knows that if a non-targeted animal were to consume ContraPest then its effects would be temporary.

With ContraPest not posing a danger to other animals or people, it’s no wonder why it is being used by many zoos, animal sanctuaries, farms, businesses and homes around the country.

SenesTech was founded in 2004 to serve women’s health. It wasn’t until researchers developed a model for inducing menopause in mice, which later became known as “mouseopause,” that they began looking at birth control technology.

Development of ContraPest took several years, but in 2016 SenesTech finally won approval from the EPA to market ContraPest for use against rats.

Now, the company has gone a step further to eliminate roof rats in elevated spaces by designing the Elevate Bait System with ContraPest, which was approved by the EPA in March.

“Elevate is a unique way to deal with a problem that no one has been able to tackle before,” Siegel said. “It enables for the first-time pest control to be easily deployed above ground. Up until this point, there was really no way to deploy poison or ContraPest above ground.

“So now there’s this groundbreaking dispensing system that you can put where the roof rats are most likely to be.”

Roof rats spend about 90% of their life four feet or more off the ground, according to Maricopa County Vector Control.

They can be found on power lines, fences, attics, garages, patios and more. So, SenesTech wanted to develop a better way to deploy ContraPest for roof rats.

The Elevate Bait System uses the same contraceptive but with a different dispensing system that’s specifically designed for roof rats in elevated indoor spaces.

The suspended bait station is easily accessible by roof rats, but out of the way of people, pets, livestock and food storage areas.

It is more than 90% effective in eliminating rat populations, according to SenesTech. This is especially important for Arizonans considering that Phoenix is ranked as one of the worst areas in the U.S. for roof rats.

It’s not just consumers who are pleased with ContraPest, the rats love it too.

“They fight over it,” said Meagher, who set up a rat camera to make sure that the rats were actually drinking ContraPest, and sure enough, they were. “

If it runs out before I fill it up, they’ll chew the container like, ‘Where is it?’ If one is drinking and taking too long, another one will bump him out of the way like, ‘Hey, it’s my turn.’ They absolutely love it.”

Rats drink about 10% of their body weight in water every day, according to SenesTech. So, ContraPest was formulated to satisfy their thirst.

The sweet, fatty liquid formula has proven successful in reducing rat populations, in turn preventing the serious property damage, dangerous food contamination and disease spread caused by rodents.

To learn more or to order ContraPest or the Elevate Bait System with ContraPest, call 1-866-886-RATS or visit