This section is 45 secs long, with soundtrack (see also "MINI CLIPS" for silent extracts)

Chapter size: 7.3 MB (.mpg) or 1.3 MB (.mov). Note: These images have been recorded with an infrared camera.

Topics and Behaviours covered: stable social dominance, fighting (escalated aggression), giving way (see commentary below)

Chapter commentary:
Lab rats have been bred to be docile, but there were signs that a pecking order was emerging. The larger rat is usually the winner of such aggressive interactions. Thereafter, the subordinate will simply give way to its superior. Such a pecking order can be remarkably stable, with individuals remaining dominant over rats they have beaten in the past long after they have outgrown them. The subordinate may accept the status quo because there is more to be gained by accepting a subordinate status than risking an all out conflict. Aggressive escalation amongst rats is rare.

Resolving conflicts is part of being social, and our naïve rats have formed a complex and efficient colony, which is now thriving. They have transformed their environment too... (see next section).