What about New York's rats?

What about New York's rats?

How did NYC's least-wanted mammals survive Hurricane Sandy?

I know what you're wondering: in the wake of the destruction caused by Hurricane Sandy, what about the rats? Images of flooded subway tunnels speak volumes about the human and financial impact. But those tunnels are not just the lifeblood of the city's transportation; they are also home to hundreds of thousands of rats.

Some rats certainly drowned. But many others survived. It's difficult to get numbers, because no one knows exactly how many rats live in New York to begin with. The estimate that New York City has "one rat per person" is largely just hearsay. In 1949 one man undertook a scientific sampling and came up with the number 250,000, but that was over half a century ago. The number could be as high as 32 million. It's really hard to say.

One thing is certain: the rat is a resourceful creature. They can climb and swim quite well; even dive. And they are good at practicing what the Buddhists call "non-attachment." When danger threatens, rats are quick to abandon their homes and flee. Rats are unsentimental that way. They do whatever it takes to survive. (Little wonder that many New Yorkers think of the rat as the city's mascot.)
 
A zoologist in this Huffington Post article points out, however, that rats are homebodies. They rarely venture far from their home territory, which means there are untold generations of rats which have never come up to the surface. They live their entire lives underground in New York's subway and sewer systems, eating discarded food and waste that washes down storm drains. 
 
These rats - never having ventured to the surface - would not have known how to get there when the tunnels began to flood with cold sea water. Many, perhaps most of New York's underground rats drowned trying to move up against the water pouring down on them from above.
 
The population of surface-dwelling rats probably survived without too many problems. Although those from flooded areas have now been displaced, if even temporarily, into drier areas. I have a feeling we will be hearing a lot about rat problems in New York's drier areas, as the rat population congregates there for shelter. Just one more problem for the human survivors to cope with.
 
Once the waters recede, how long will it take for the underground population to be re-established? It's difficult to say since, for an animal that is so famous and causes so many issues, New York's underground rats are not well studied.