Week 2

Welcome back!

Week 2 really began my work on my project. I learnt about the five categories of aggressive behaviors typically seen in BALB/c strains of mice. Based on Bret’s observation and familiarity with the mice, we developed a scale to rate behaviors at different levels of aggression. 

Score Sheets for Behavior Recordings

1 – Posturing: Posturing is defined as those behaviors that are not overtly aggressive but that are performed by the aggressor in the cage to show signs of dominance to the other mice. Common types of posturing behaviors include chasing, pouncing, barbering, vibrissae and mounting. Posturing behaviors tend to be one sided, unlike scuffles. 

2 – Scuffling: Scuffling, unlike posturing, involves a two-sided party in the incident and implies that aggressive behaviors were displayed by both or all of the animals involved in the scuffle.

3 – Biting: One of the more straight forward behaviors, biting is easy to spot and often leaves the recipient licking their wounds, an indication that blood was drawn. Biting can be of two general forms, the first is to condition, in which the aggressor in the cage will bite in the early hours of the second day to establish his place as the alpha. The second is more common among the later days of the study, where the dominant mouse will repeatedly bite the other mice to remind them of his place in the cage hierarchy. 

4 – Behavior resulting in an open wound: In cages where multiple mice have aggressive tendencies and have to fight to dominate the cage, biting is one of the most common and most vicious behaviors that also tends to lead to open sores and cuts among the other mice in the cage. These animal, so long as they are not posing a significant threat to themselves or any of the other animals are left alone.

5 – Behavior resulting in severe injury or death and the consequent removal of the injured mice from the study.

This week was really interesting and it was also my first glimpse into what my day to day job in the laboratory would be like. The videos proved to bring some significant challenges in terms of camera placement, amount of bedding given in the cage and size of the mice in the video. At lab meeting this week Bret presented some of his preliminary data from Day 2 and we spent some time talking about the different ways that data could be analyzed. 

Thanks for reading! See you next week!

Tasha