A Rat’s Tale: Ancient Enemy or Furry Friend?

Rattus norvegicus  , a domesticated brown rat, a.k.a. a fancy rat (Apparently he left his top hat and cane at home…).  Photo courtesy of:  http://www.flickr.com/photos/necilbug/2403405178/  

Rattus norvegicus, a domesticated brown rat, a.k.a. a fancy rat (Apparently he left his top hat and cane at home…).

Photo courtesy of: http://www.flickr.com/photos/necilbug/2403405178/ 

Rats. They have a bad rap that goes back thousands of years, and lives on today as strong as ever. In fact, ask a few random people what they think of rats and you'll generally get reactions ranging from a silent shudder of horror to “Ew! They have beady eyes and snake tails!” Yet these same people seem to have no problem letting a dog lick their face…so what’s the deal? Why do people almost universally revile these furry creatures? Well, it probably started sometime around the 14th century in Europe… something about rats carrying a plague that wiped out roughly half the population. Or maybe it's due to their propensity for integrating themselves into our modern day urban landscapes, popping unexpectedly out of sewers, subway tracks, dumpsters, and just about any other undesirable place you can imagine, sometimes in sizes larger than you can imagine. Either way, most people lack a fondness for rats, and many are downright repulsed by them. OK, OK, maybe they have a point...rats do tend to live in all kinds of decidedly creepy locations, and they may have been somewhat involved in that plague thing, even if the fleas were mostly to blame. I, however, feel compelled to leap to their defense.

If only the subway rats looked more like this…  Photo courtesy of:  https://www.flickr.com/photos/twopinkpossums/3623965031/

If only the subway rats looked more like this…

Photo courtesy of: https://www.flickr.com/photos/twopinkpossums/3623965031/

I guess this is as good a time as any to come clean…I got my first rat at age 10, and went on to have a series of rats throughout my childhood. Which, I suppose, may make me somewhat biased in the matter. However, for a budding scientist, rats were the perfect pets. Their impressive intelligence allows them to learn a variety of tricks. I trained my rats to walk on their hind legs, run mazes, and, on a particularly ambitious day, play in a one v. one soccer match (it ended in a tie…they couldn’t quite master penalty kicks).  My rats also became accomplished escape artists. On one memorable morning, I  watched Freckles hold the top of the cage open, allowing her sister, Butterscotch to escape (needless to say, my mom was somewhat displeased, as was Butterscotch when she couldn’t figure out how to get back inside). Apparently this type of cooperative escape behavior has been studied, with rats consistently helping a caged companion escape, even a companion that is unfamiliar to them. In fact, when a desirable food treat (a chocolate chip- clearly rats and humans aren’t SO different) was made available, rats still freed their caged companion first, and then shared the food. Scientists have termed this “empathetically motivated pro-social behavior”, and use it as evidence of the biological roots of empathy motivated helping behavior in humans (Bartal et al., 2011). So yeah, not only are they smart, but rats even watch each other’s backs.

Rats also possess excellent senses of hearing and smell, and utilize their tails to maintain their extraordinary balance, which allows them to perform all kinds of mind-boggling athletic feats. I would watch in awe as my rats easily jumped two feet straight up to the edge of their aquarium and waltzed effortlessly around the edge, or leapt casually onto a pencil from a table three feet away. Have I mentioned that rats are immaculately clean? Not only do they compulsively clean themselves after every meal, but they also divide up their cage, creating dedicated bathroom, sleeping, eating and play areas. As you can imagine, their intelligence and complex behaviors made rats ideal pets (or continual test subjects, depending on how you look at it) for a young scientist. I filled countless notebooks with observations of my rats, and in one case stayed up all night to see if they were indeed nocturnal. I could never understand why my classmates preferred hamsters or gerbils, which seemed downright boring compared to my precocious pets. And I’m not the only one—many of my scientist friends had similar experiences with pet rats as a child…check out this video if you need further convincing of their athletic prowess and all around awesomeness:

Who needs an ark? Drawing by Catherine Caruso

Who needs an ark? Drawing by Catherine Caruso

To add to their long list of attributes, rats can also survive a 50 foot fall, squeeze into quarter-diameter openings, and have teeth that are a 5.5 on the Mohs Scale of Hardness, which is harder than iron or platinum, and allows them to easily gnaw through concrete and metal. Rats are also excellent swimmers, able to tread water for up to three days, dive to 100 feet and hold their breath for ten minutes. As a child, I felt compelled to test this last fact myself, with the assistance of large salad bowl full of water (I conveniently waited until my mom was out running errands). Alas, when I dropped my rats into the bowl, they bobbed under water for a second, and immediately surfaced, slipping into a casual but effective doggy (ratty?) paddle. In fact, the phrase “Like rats deserting a sinking ship” came about centuries ago because stowaway rats living deep in the hulls of wooden ships were often the first to realize the ship was sinking, and would jump overboard en masse to swim to safety. Rats were often found treading water or clinging to debris long after the ship and all the humans aboard had gone down. Recently, the phrase has been adopted into the political realm, as evidenced by a quick google search, but regardless, the historical and biological basis remains. To go biblical for a second, this means that rats probably would have survived the big flood, even without the ark.

So, going back to the whole plague/urban rat thing for a second, while rats may sometimes end up in places where we don’t want them, you have to admit that as a species, these little guys are seriously scrappy. Like cockroach level scrappy. They have found a way to thrive in virtually every habitat that exists, dramatically altering their behavior based on their environment…impressive, but unsurprising considering their intelligence, athleticism, and super-senses (and their rapid reproductive abilities don’t exactly hurt). Which brings me to my main point—while it may be easy to dismiss rats as creepy or dirty, I ask you to give them a second chance. There is more to them than initially meets the eye, whether you admire them for their super survival skills, or desirable pet qualities. Personally, I will always think of rats as my inquisitive friends, constantly ready to go on an adventure, or just sit on my shoulder and watch the world go by.

About the Author

Catherine Caruso is a master’s student in the Berlinsky Lab at the University of New Hampshire. Despite the post above, she actually studies fish, not rats, and is focusing on how temperature affects sex differentiation in summer flounder. She is, however, a long- time rat admirer.  

Be sure to check out her blog: Doing Science, One Day at a Time

References and Additional Information

Bartal, I.B.A., J. Decety, and P. Mason. (2011). Empathy and pro-social behavior in rats. Science 334(6061): 1427-1430.

Galef, B. G. (1980). Diving for food: Analysis of a possible case of social learning in wild rats (Rattus norvegicus). Journal of Comparative and Physiological Psychology 94(3): 416-425.

Meaney, M. J., and J. Stewart. (1981). A descriptive study of social development in the rat (Rattus norvegicus). Animal Behaviour 29(1): 34-45. 

A New Model of Empathy: the Rat - Washington Post

Inside the Rat Pack - The Humane Society of the United States

Rat Care - ASPCA.org