1. Territory and Navigation
Part II Navigation

2. Navigation We talked about territoriality
To get around a territory an animal must know where it is going
Indeed, for most any animal that moves, it needs to have a way of knowing where it has been and where it is going
There are many ways this can be accomplished, from complex cognitive mechanisms to simple odour trails

3. Path Integration Simplest form of navigation that uses memory
Cataglyphis, the Long Legged Desert Ant
Twisting outgoing path, but a direct path home.

4. Path Integration Animal Stores direction and distance
Simple vector mathematics
Animal must maintain a running calculation
Error will be cumulative
How could it be improved?

5. Path Integration and Landmarks
While ‘integrating’ the animal could, periodically, take a fix.
Probably from the stars or the sun
Clock shift experiments show this to be true!
Same thing sailors used to do with a sextant (or a GPS today)
But stellar position changes over time, animal cannot have stellar positions hardwired!

6. Beacons and Landmarks A beacon directs behaviour towards it
A landmark points toward a goal, along with other cues
Both are used by many animals
There have been some great strides made in understanding various species’ use of landmarks in the last 20 years

7. Bees!!
So, the bee seems to be matching the SIZE of the retinal image with the size of the image in memory
Colour change has no effect
Making the landmark a ‘wireframe’ has no effect
Training
Half size test
Double Size test

8. Two Landmarks Bees are sort of half using angular information
Training
Stretch Test
Bees are sort of half using angular information
3 Peak places of search in the Stretch test
Collett, Cartwright, Cheng and their colleagues
Rotation Test

9. Landmark Use in Pigeons
Ken Cheng’s (1989) work
Landmark
Goal

10. Tests of Pigeon Landmark Use
Search
Animal searches along the same axis of landmark shift
Does not COMPLETELY follow the landmark
But, does not shift search in the other direction

11. Further tests of….
Now the shift is up down, so the animal searches in the ‘up/down’ axis
Landmark
Search

12. The Vector Sum Model
Cheng concluded that the pigeons must be adding self – goal and goal to landmark vectors.
This is the only model that explains the search patterns
Eureka!

13. Conclusions Animals can use many sources of information to navigate
Multiple sources usually point to the same place
Hierarchical representations I think