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Hurricane Sandy's Aftermath: Will Rats Take Over Manhattan?

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"The 8-million-strong human population of New York City is matched, if not exceeded, by the city's number of rodent dwellers," says Lynne Peeples at The Huffington Post. And lots more rats lost their homes — subway tunnels and sewers — to flooding from Hurricane Sandy than people did. What has become of those disease-carrying vermin?

"Rats are incredibly good swimmers," says Rick Ostfeld of the Cary Institute of Ecosystem Studies, ominously. "And they can climb." If Sandy did indeed flood them out and upset their social structure, "rats could start infesting areas they never did before," and the result could be a public health mess, with potential outbreaks of leptospirosis, typhus, salmonella, even the plague. In other words, "a rat disturbance is something we should be concerned about."

Well, so far at least, the "ratpocalypse that threatened to destroy humanity (at least in New York)" hasn't materializedsays Dan Amira at New York. There's been no notably increased above-ground presence of the rodents, and "in fact, the flood may end up as a net positive, as far as we people are concerned." Why? Flooding kills young rats, so the overall rat population may well decrease.

Unfortunately, it's not that simple, says Adam Clark Estes at Vice. Many, if not most, rats will drown, but "those that make it out of the flooding will be treated to a veritable feast of garbage and debris that washed into the tunnels during the hurricane," and they'll be able to gorge and reproduce freely in the deserted subway stations. And if the flooding killed the submissive rats that scavenge for food in the daytime, leaving the dominant, nocturnal rats alive, "New York's rat population may have just gotten stronger."

This fixation on a great rat invasion makes sense after a calamity like Sandy, says Robert Sullivan at The New Republic. "We find rats terrifying, a measure of the breakdown of everything we think of when we think of civilization." But it's important to remember that "rats rarely live up to headline writers' fantasies." Let's start by debunking the myths: First, there aren't 8 million rats in New York; there are more like 250,000. Second, "hordes of Norway rats, North America's predominant rat species, do not live deep in the subway tunnels," they live where the food/garbage is — on the subway platform and in parks:

After September 11, rat populations increased in Lower Manhattan precisely because the area was cut off to people. Restaurants near the old World Trade Center that were abandoned were suddenly akin to rat farms... The Lower Manhattan rat population increased dramatically, and, as a result, the city Department of Health built a ring of poison-filled bait stations around the abandoned areas, eventually beating down the population explosion. This week's flooding just means... Keep your food secure and be vigilant.... And we know that after a flood event, the water itself — contaminated with raw sewage, as well as petroleum products and all the not-as-terrifying pollutants that normally cover our streets — is potentially more of an issue in terms of spreading pathogens than rats.

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Weather Watch
Rising Temperatures Are Killing Off African Wild Dogs
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Over the last few decades, images of fluffy white harp seals, polar bears, and penguins have become shorthand for climate change's creeping destruction of our planet. But the poles aren't the only ecosystems in danger. A new study published in the Journal of Animal Ecology finds that rising temperatures near the equator are making it much harder for African wild dogs to survive.

"When people think about climate change affecting wildlife, they mostly think about polar bears," lead researcher Rosie Woodroffe of the Zoological Society of London told The Guardian. "But wild dogs are adapted to the heat—surely they'd be fine."

To find out, Woodroffe and her colleagues analyzed data from packs of African wild dogs (Lycaon pictus) in Kenya, Botswana, and Zimbabwe. The dog packs have been under scientist surveillance for years—some since the late 1980s—and at least one dog per pack is fitted with a radio collar.

The researchers overlaid information about local weather and temperature with data on the dogs' hunting habits, the size of each litter of pups, and how many pups from each litter survived.

These dogs are creatures of habit. Adults rise early and leave the den for a morning hunt. They range over their large territories, chasing antelopes. At midday, when the Sun is highest, they return to their pups with food. They may go out again in the evening as the temperature drops.

But like the polar bears' glaciers, the dogs' environment is gradually heating up. All three countries saw a temperature increase of about 1.8°F over the study period. This may not sound like much, but for the dogs, it was plenty. Between 1989 and 2012, the number of pups per litter in Botswana surviving to their first birthday dropped from 5.1 to 3.3. Dog packs in Zimbabwe saw a 14 percent decrease in pup survival; in Kenya, the rate declined by 31 percent.

"It's really scary," Woodroffe said.

"If you are an animal who makes your living by running around really fast, obviously you are going to get hot. But there are not enough hours in the day anymore that are cool enough to do that. It is possible that some of these big areas will become too hot for wild dogs to exist."

Woodroffe and her colleagues were not anticipating such clear-cut results. "It is shocking and surprising that even right on the equator these effects are being seen," she said. "It illustrates the global impact of climate change." 

[h/t The Guardian]

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Big Questions
Where Is the Hottest Place on Earth?
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The summer of 2017 will go down as an endurance test of sorts for the people of Phoenix, Arizona. The National Weather Service issued an extreme heat warning, and planes were grounded as a result of temperatures exceeding 120 degrees. (Heat affects air density, which in turn affects a plane’s lift.)

Despite those dire measures, Phoenix is not the hottest place on Earth. And it’s not even close.

That dubious honor was bestowed on the Lut Desert in Iran in 2005, when land temperatures were recorded at a staggering 159.3 degrees Fahrenheit. The remote area was off the grid—literally—for many years until satellites began to measure temperatures in areas that were either not well trafficked on foot or not measured with the proper instruments. Lut also measured record temperatures in 2004, 2006, 2007, and 2009.

Before satellites registered Lut as a contender, one of the hottest areas on Earth was thought to be El Azizia, Libya, where a 1922 measurement of 136 degrees stood as a record for decades. (Winds blowing from the nearby Sahara Desert contributed to the oppressive heat.)

While the World Meteorological Organization (WMO) acknowledged this reading as the hottest on record for years, they later declared that instrumentation problems and other concerns led to new doubts about the accuracy.

Naturally, declaring the hottest place on Earth might be about more than just a single isolated reading. If it’s consistency we’re after, then the appropriately-named Death Valley in California, where temperatures are consistently 90 degrees or above for roughly half the year and at least 100 degrees for 140 days annually, has to be a contender. A blistering temperature of 134 degrees was recorded there in 1913.

Both Death Valley and Libya were measured using air temperature readings, while Lut was taken from a land reading, making all three pretty valid contenders. These are not urban areas, and paving the hottest place on Earth with sidewalks would be a very, very bad idea. Temperatures as low as 95 degrees can cause blacktop and pavement to reach skin-scorching temperatures of 141 degrees.

There are always additional factors to consider beyond a temperature number, however. In 2015, Bandar Mahshahr in Iran recorded temperatures of 115 degrees but a heat index—what it feels like outside when accounting for significant humidity—of an astounding 163 degrees. That thought might be one of the few things able to cool Phoenix residents off.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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