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Territory and Navigation

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

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Territory and Navigation

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  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 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 • Animal searches along the same axis of landmark shift • Does not COMPLETELY follow the landmark • But, does not shift search in the other direction Landmark Search

  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

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