In all of the excitement and concern in the aftermath of Superstorm Sandy, many people’s attentions have turned to rats?
And one that hits a little closer to home:
It spurred some comments, mostly tongue-in-cheek and humorous – after all this is what Luvvie’s stock and trade.
But I see many opportunities for this to be a learning moment. Many folks had questions or made comments that indicated they didn’t understand rats and these rats in particular. The rat in the photo is not the common sewer or subway rat, Rattus norvegicus, but is something else altogether. It is very likely an African Giant Pouched rat or Gambian rat, Cricetomys gambianus. I study these rats and when I first saw the news of the Giant Rat Killed With Pitchfork At Brooklyn's Marcy Houses I looked closely and thought this might be the rats I [will] study.
The experts who were questioned also agreed. So, this brings even more concern about the Invasive potential of Cricetomys in the United States.
First things, first: these are not mutant, genetically modified, nuclear power-plant created rats. They can get big. This picture of the dead rat from the Marcy Project sproves that, but most aren’t dog-sized. Rat terrier-size? Okay, I’ll concede that.
African Pouched rats are different than ‘regular rats’. How can you tell the difference?
Size. Yes, Pouched rats are larger than regular rats, they can measure up to 2 feet long from tip of nose to tip of tail, but the body is about 12-14 inches in adult rats.
But a more reliable distinction is in the coloration.
Tail Color. The tail of Pouched rats is bi-colored. The lower half of the tail is white or pale grey. Sewer rats have a uniformly grey or brown (solid colored tail to the tip).
Belly fur color. Pouched rats have a white or cream-colored belly: countershading. Sewer rats do not have a sharp color distinction of the back and belly.
But it seems there are big, over-sized rats in New York, especially in the projects. Why is that?
It’s probably because of the food they are eating. Rats in urban areas tend to be denser in areas where there are more people and more trash and more restaurants. If Brooklyn is like most other Metropolitan areas, then trash and pest control services are probably a little sketchy in the poorer parts of town. The improper disposal of trash provides lots of great feeding opportunities for rodents and slow pest control services gives them ample opportunities to breed and spread out.
Having so much access to so much food in a central location promotes fat rats. They don’t have to travel far to find a good food source. And they don’t have enough predators to keep their numbers in check. Stray cats and dogs can pick off smaller rats, but larger rats are too much of a hassle for these predators. Natural wild enemies like raptors, foxes, and coyotes are not abundant enough in urban areas like Brooklyn to have enough of an impact.
So to answer the question: Will Giant Mutant Rats overrun NYC in Sandy’s wake?
Nope, not at all.
Will these large African Rats takeover New York and finish what Sandy started?
I don’t think so. We still aren’t 100% sure that these are Gambian rats in the projects, though I think they may be. To be 100% certain we would need a specimen to inspect, get some genetic sample and ideally a voucher. To my knowledge that was not done with the Marcy Project rat. Dang! I would’ve bagged that beast and threw it in my mom’s deep freezer until I could have mounted that joker. (IJS, I’m a mammalogist. It’s what we do!).
Yes, these rats are good climbers and are likely to be good swimmers, too. Assuming there are African Pouched rats in New York City, they are survivors, but it doesn’t seem there is a viable population to threaten the safety of the general public.
Learn more about NYC Rat Refugees with SciAm's own @BoraZ on HuffPostLive.
Have any other questions about these ROUSs (rodents of unusual size)?
Then ask away.