Scientists Create Squirrel Contraceptive to Save UK’s Trees

  • Wonder when they’ll develop a Nutella-based contraceptive for people?

When you want to do the horizontal mambo without offspring, it’s a simple solution — use a contraceptive. But try telling that to animals.

More specifically, gray squirrels. Environmentalists in the U.K. are struggling to deal with an overwhelming onslaught of the tree-climbing rodents.


The traditional method of dealing with the squirrels is a rather brutal and straightforward cull. But that doesn’t really because the varmints love to get their freak on.

As a result, a cull isn’t an effective solution. The critters simply repopulate the area in a short time.

Also, environmentally-minded folks aren’t really on board with an all-encompassing squirrel genocide.

But now, they just might have a way to solve their squirrel woes. U.K. scientists have developed a contraceptive that stops squirrels from spawning out of control.

Killing the Mood

How does the squirrel contraceptive work, though? Did the scientist develop tiny rodent-sized condoms?

Funny as that would be, they didn’t. Instead, the contraceptive is a vaccination.

Dr. Giovanna Massei from the U.K. government’s Animal and Plant Health Agency (APHA) is the lead scientist on the contraceptive vaccine. She said it’s a more humane solution than a mass killing — and potentially more effective.

In an interview with the BBC, Massei explained the vaccine affects the squirrels’ immune systems. The shot restricts the production of sex hormones, which leaves both male and female squirrels infertile.

Whether they still feel the urge for squirrel sex, Massei didn’t say.

Computer models show that the drug could completely eradicate squirrels in a given area. As long as new squirrels don’t immigrate in, the critters will disappear on their own.

Despite being non-lethal, you might think it’s cruel to slowly annihilate a population through old age. Well, our squirrel-loving friends, don’t you worry — the vaccine’s effects aren’t permanent.

The squirrels will eventually get their sex drive back, although Massei’s team is working to maximize the vaccine’s effects. But even a short break in breeding could help the U.K.’s ecosystem get a much-needed break.

Nutella to the Rescue

Right, so the contraceptive is a vaccine, but how do you get squirrels to take it? You can’t exactly hope for them to wait in line at a pharmacy.

The answer is Nutella.

Well, not necessarily Nutella, but a hazelnut spread. Gray squirrels go absolutely bananas for the stuff — trials in Yorkshire and Wales found that 70% of an area’s squirrels visited traps loaded with the treat.

It seems the squirrels are rather unique in their thirst for Nutella. The only other creatures that managed to find their way into the traps were two mice — and we don’t know if the hazelnut spread attracted them or if they just managed to wander in.

Since the squirrels love Nutella so much, it’s an easy job for the researchers to inoculate a population. All they have to do is mix the drug into the bait and let the squirrels come and wolf it down.

A Much-Needed Drug

Vaccinating squirrels by using drug-loaded Nutella might sound like a ridiculous process, but it’s sorely needed. Gray squirrels are a real plague on the U.K.’s forests.

The animals aren’t native to the British islands. They found their way over from North America in the 19th century, and they noticed that the U.K. is a fantastic place for them to live.

According to estimates, there are currently about 2.7 million gray squirrels in the U.K. This ravenous horde is making short work of the country’s trees.

You see, in addition to Nutella, gray squirrels love eating sweet, nutritious tree sap. They’re just a bunch of sugar addicts.

But to get to the sap, the squirrels will strip away the bark of various trees, particularly oak, beech, sweet chestnut, and sycamore. Without their protective layer, the trees are left vulnerable to parasites and diseases.

The squirrels are killing off so many trees that they’re an active hindrance to the U.K. government’s plans to control climate change by planting more trees. But they’re also a threat to Britain’s native squirrels.

The gray squirrels compete with the British red squirrels. Although it’s less of a competition and more of a slow war of attrition that the grays are squarely winning.

Gray squirrels are bigger and stronger than red ones, which means they can beat the native critters in a fight for food. They also carry the squirrel pox virus, which they’re immune to — but red squirrels aren’t.

The red squirrel is now facing extinction throughout the U.K. Experts estimate there are 160,000 red squirrels left on the British Isles, with only 15,000 in England.

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