Archive for November 11, 2008
Since our last update, we have made a couple of changes to our hoarding experiment:
1) In order to make the experimental tank more like the familiar home environment, we are incorporating a “cubby” (small tissue box) in which we place a small wash cloth that is covered in each rat’s sent. The cloths are kept in each rat’s cage 24/7 and are currently covered in urine and other rat smells! We place the tissue boxes in the cages for about an hour each day in order to make the rats familiar with them. Unfortunately, we cannot leave the boxes in the cages all the time because they take up so much of the already limited space, and Louise and Penelope have been chewing on them (Louise especially!)
Here is a picture of a tissue box and wash cloth inside Penelope’s cage.
We have found that when the “cubbys” are present and we deliver food to the rats, they bring the food into the cubbys nearly 100% of the time.
2) We redesigned the apparatus to give the rats a larger space, as well as to make the experimental situation more like a rat’s natural hoarding environment. We switched to a much larger tank, and used a newly designed wire mesh divider to split it in half longways. Thus, we are able to give them more space, while also maintaining the option of testing the rats together as well as alone as we had originally planned. We chose to give them long rectangular spaces rather than wider square spaces because this allows us to place their food further from the hoarding area, making them travel further for the food, and making the situation at least a little bit more natural. Additionally, each rat is kept on a specific side and the tank is deodorized using a natural cleaner between every trial.
Here is a picture of the new apparatus with Louise’s box (and Louise’s tail!) included.
To make things more clear, here is a representation of the above apparatus.
The following drawing represents the set up we will use when if/when we put both rats in the tank to assess how much they hoard when they are together.
Finally, we have included a video showing Penelope’s behavior when we added the tissue box to the experiment (this was not official, we simply wanted to see what she would do.)