Ratpocolypse, flood of rats, the ra(p)ture…Ever since Hurricane Sandy flooded New York City’s subway systems, reporters have been waxing biblical as they wonder: what happened to all the rodents who once scampered and snacked in New York City’s tunnels? People aren’t sure how many rats there were to begin with—28 to 32 million, perhaps—but though many may have died in the storm, people expected to see swarms of them appearing on the street after the storm, feasting on tasty, soggy storm debris. So far, New Yorkers seem to have been spared that sight.
When rats were injected with a chemical similar to marijuana’s main ingredient, THC, shortly after a undergoing a severely stressful event, they showed a significant reduction in symptoms like those seen in people with post-traumatic stress disorder. The study tested a synthetic cannabinoid called WIN 55,212-2, which was injected directly into the animals’ amygdala, a brain region involved in the regulation of emotions like fear and anxiety. Timing was important. Rats given the drug two and 24 hours after the stressor—being forced to swim for 15 minutes—appeared less “traumatized” when tested a week later, compared with those given the drug 48 hours later or given no drug at all. While the study adds to the already large and complex pile of evidence that the cannabinoid system has a vital role in regulating emotions like anxiety, it’s far from proving that cannabinoids will be useful for treating PTSD in humans.
Enormous stone statues, called moai, on Easter Island
What’s the News: Easter Island is often held up as an example of what can happen when human profligacy and population outpace ecology: Wanton deforestation led to soil erosion and famine, the story goes, and the islanders’ society declined into chaos and cannibalism. But through their research on Easter Island, paleoecologists Terry Hunt and Carl Lipo have unearthed evidence that contradicts this version of events. The Polynesian settlers of Easter Island prospered through careful use of the scant available resources, they argue in their new book The Statues That Walked; the island’s forests were done in not by greedy humans, but by hungry rats.
Left: normal rat disc. Right: engineered disc.
What’s the News: Researchers at Cornell University have now bio-engineered synthetic spinal discs and implanted them in rats. The implants provide as much spinal cushioning as authentic discs do, and improve with age by growing new cells and binding to nearby vertebrae, according to the study recently published in the journal PNAS. The research could someday help people with chronic lower back and neck pain from conditions like degenerative disc disease.
What’s the News: In the animal kingdom, prey species must follow one rule above all others: keep away from predators. To do this, some animals take chemical cues from the urine they stumble upon. Now, new research published in the Proceedings of the National Academy of Science has identified a single molecule in the urine of many mammalian carnivores that causes rodents to scurry in fear. This chemical could eventually help scientists understand instinctual behavior in animals.
What’s the News: After running aground last week on a remote island off the coast of South Africa, a freighter has leaked over 800 tons of fuel oil, coating an estimated 20,000 already-endangered penguins. “The scene at Nightingale [Island] is dreadful as there is an oil slick around the entire island,” said Tristan Conservation Officer Trevor Glass said in a statement. But even worse, authorities fear that the rats from the soybean-toting ship will swim to the island and destroy the bird population.
What’s the Context:
The Future Holds: Though a salvage tug left Cape Town, South Africa, last Thursday, the earliest it will arrive to help remove fuel is this Wednesday. With little to salvage, authorities say that cleanup is now the main task at hand. As Jay Holcomb, the director emeritus of the International Bird Rescue Research Center, told the New York Times, “Many of the birds have been oiled for over a week, which limits their chances of survival.”
Image: Wikimedia Commons / Arjan Haverkamp
Last week DISCOVER brought you the sad and somewhat counter-intuitive study that suggested loneliness could actually be “contagious” and spread across a social network. Now more bad news for the lonely. In a study (in press) in the Proceedings of the National Academy of Sciences, another team of researchers argues that, in rats at least, loneliness can increase cancer incidence.
The scientists separated their test rats at birth, keeping them either in groups of five or alone. Those kept alone had a 135% increase in the number of mammary tumours, a 8,391% increase in the size of tumours and a 3.3-fold increase in the relative risk of malignancy [Nature News]. They also showed higher levels of the hormone corticosterone, which is connected to stress.