I recently came across two very different approaches that municipalities are taking in attempts to control rat population.
One series of articles highlights the work of SenesTech, a technology company based in Flagstaff, Arizona. SenesTech works to reduce rodent populations not by employing massive amount of rodenticides but by feeding them chemicals which makes them infertile.
In an article from 2013 Bloomberg reported on New York’s impending use of SenesTech technology to sterilize rats in the Subway system. An interesting part of the plan is that the target was to reduce the rat population by 75%. I am assuming that they only wanted to go to 75% to prevent new rat colonies from moving in??
A second series of articles highlights the use of dry ice (carbon dioxide) to suffocate rats in their burrows. The approach is summarized in a report from USA Today which indicates that Chicago and New York will be trying this approach following the success that was seen during trials in Boston.
The general concept is pretty simple. Shove a bunch of solid dry ice into a burrow and it will release carbon dioxide gas as it melts. The burrow will fill with carbon dioxide and any rats inside will suffocate.
Update 12/2/16: It looks like the EPA has ruled that it is illegal to use dry ice to suffocate rats. Who knows what those folks are thinking!
Both approaches are innovative ways to eliminate rats on a large scale that do not rely upon hazardous poisons. I like the innovative thinking and look forward to seeing how well these techniques actually work!