Animals that don't Exist

The Beaver Rat

The beaver rat, Rattus castor, is a member of the rattus genus that lives exclusively in the sewers of big to medium-sized cities. Its name comes from its tendency to build dams along sewer lines, reminiscent of the behavior of its larger cousin, the beaver. But, although in both cases, the construction of dams is intended to better the habitat of the builder, beaver rats use their skills in much more complex ways than beavers.

Beavers build dams to flood their living area, giving them better protection from land-based predators, such as cougars, as well as shelter. But beaver rats make constructions that do not directly benefit them. Indeed, what the beaver rats are trying to achieve is to manipulate human behavior by constructing dams in the sewers, so that the maintenance that follows suits their needs. Expanding waterways, cleaning up excessive rubbish, closing off some tunnels, digging new ones, beaver rats have become master manipulators of urban planning. And for a long time, they did so without anybody being the wiser. It was only when Anna Therscientist started a long term study of sewer rat behavior for her Phd at the New York Institute for Stuff that Most People find Distasteful but that's Actually Really Cool (NYISMPDARC) that we became aware of the phenomen.

Her research suggests that most of this behavior is a cultural trait, inherited not through genes but through learning from the community. She has done several experiences where she introduced young rats from laboratory populations into the ones existing “in the wild”, and they have been able to copy and innovate on the behavior of their new compatriots, albeit their learning rates being slightly inferior to those of the natives, and their innovations less succesful. However, how the rats came to adopt this behavior in the first place remains a mystery.

“The time between the construction of a particular dam, or the blocking of some access, and human intervention, can be very long in terms of the animals' life-span. This suggests that they either have very good memory that allows them to link cause and effect over long timespans, or that they are able to infer consequences of their actions on a logical basis, without needing positive feedback to learn any given behavior. Both cases would drastically change the view we've had of animal intelligence and learning so far.”