Part 9: Mechanisms of Orientation and Navigation

Question 1

Piloting

Answer 1

the ability of an animal to find its way using LANDMARKS.

• includes: visual, olfactory, magnetic, etc.
• Ex. black rhinoceros - poor vision/memorize home/visual landmarks; salmon - olfaction + natal stream

Question 2

Compass Orientation

Answer 2

the ability of an animal to find its way WITHOUT using landmarks.

• animal keeps a certain angle toward an external reference system (e.g. magnetic fields, stars, sun) used as a compass.
• AFFECTED BY DISPLACEMENT
• Ex. starlings - displaced prior to migration + off from true destination by magnitude of displacement

Question 3

Vector Navigation

Answer 3

an inherited program telling an animal the compass direction to head in and for how long.

• a subset of Compass Orientation
• Ex. blackcap warblers - bred individuals w/ diff. migration destinations&raquo_space; offspring migrated to intermediate destination

Question 4

Path Integration

Answer 4

(a. k.a. DEAD RECKONING) the process by which an animal integrates information on the sequence and direction and duration of each leg of an outward journey and uses that information to return.
- a subset of Compass Orientation

Question 5

True Navigation

Answer 5

(a. k. a. “Homing”) an animal’s ability to maintain or establish reference to a goal, regardless of its location, without the use of landmarks.
- UNAFFECTED by displacement

Question 6

Hierarchy of Navigational Mechanisms

Answer 6

A navigational system may involve more than one sensory system.
- use multiple orientation cues

Question 7

Visual Cues

Answer 7

the use of visual landmarks and celestial inputs

Question 8

Landmarks

Answer 8

an easily recognizable (VISUAL) cue that can be stored quickly in an animal’s memory to guide it on a later journey.
Ex. digger wasp - removed pine cones around ground burrow&raquo_space; could not locate nest

Question 9

Sun Compass

Answer 9

navigation using celestial cues such as the position of the sun.

• a VISUAL cue
• REQUIRES an INTERNAL CLOCK (e.g. circadian rhythm)
• sand flea - retrained internal clock in laboratory to opposite&raquo_space; no longer moved with tides/moved in opposing direction

Question 10

Polarized Light (Cue)

Answer 10

a visual cue some animals, notably insects, are sensitive to (the polarization of light)

• Ex. honeybees + Karl von Frisch = waggle dance instructions to food source
• employed in overcast conditions (light polarized by water vapor)

Question 11

Polarized light may be used for orientation in two ways:

Answer 11

1. As an axis for orientation

2. To determine the sun’s position when blocked from view

Question 12

Star Compass

Answer 12

navigation using stars/nightsky as a visual cue, another “celestial cue” (like Sun Compass)

• Ex. warblers placed in planetarium and rotated to South (following constellations) as the sky was manually shifted
• REQUIRES “sextant and chronometer”
• REQUIRES an INTERNAL CLOCK

Question 13

Magnetic Cues

Answer 13

an orientation cue some animals are sensitive to (earth’s magnetic field)
- homing pigeons - use w/ other cues (cannot navigate well when overcast&raquo_space; disrupts magnetic field)

Question 14

Which aspects of Earth’s magnetic field are useful for orientation?

Answer 14

• Polarity
• Angle of Inclination
• Intensity of Magnetic Field

Question 15

Polarity Compass

Answer 15

The polarity of earth’s magnetic field allows animals to distinguish between poles.
Magnetic south pole = negative pole
Magnetic north pole = positive pole
- AFFECTED BY POWERLINES

Question 16

Angle of Inclination

Answer 16

the angle that the line of force makes on the horizon

Question 17

Inclination Compass

Answer 17

Inclination of force allows animals to distinguish between poleward, where lines of force are steepest, and equatorward, where lines of force are parallel to Earth’s surface.

Question 18

Poleward

Answer 18

The lines of force are steepest when nearing the poles

Question 19

Equatorward

Answer 19

The lines of force are parallel to the Earth’s surface