The Animal Movement Extension was written in Avenue, and development stopped many years ago. Therefore, Animal Movement Extension is not available for ArcGIS 9.x or 10.
There are a couple of options if you'd like to move forward with ArcGIS
A lot of people using Animal Movement extension migrated to Hawths Tools, to be able to use ArcGIS. Hawths tools offered many of the functions in Animal Movement, though Hawths tools is also now a discontinued project, and will not work with newer versions of ArcGIS (9.2 was the last version it worked with).
Hawths tools has been been merged into the Geospatial Modeling Environment, which works with ArcGIS 10. You can download this and find more info at: http://www.spatialecology.com/gme/
There is a lot of work going on with Agent Based modeling right now. I met with an agent based modeling working group at the ESRI conference. They've developed an extension for ArcGIS based on repast called Agent Analyst: http://www.institute.redlands.edu/agentanalyst/ . I didn't hear about any scenarios involving wildlife movement, buy there is a book coming out, and I would assume those scenarios might be discussed. I'll keep my ear to the ground on this one
There are also contributed and native tools and scripts that could be used to perform many of these functions if strung together in the right order