Territory and Navigation Part II Navigation

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

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

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?

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!

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

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

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

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

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

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

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!

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