MagnetoreceptionDan Shearen

Magnetoception

•Is the ability to sense magnetic fields created by the earth.

•Then use these sensations for example in instinctively knowing which direction is north.

•In animals this can be used for migration.

The Ethmoid Bone•Has a small magnetic

deposit inside of it, giving humans the ability to sense

magnetic fields.

•Much like animals, such as pigeons which have it in their

beaks.•Though unlike birds, it is

believed that this function of the ethmoid bone is vestigial.

Animals•Unfortunately not much research has

been done on humans.

•Most animals that have this ability have two types of magneto-receptors.

•One that detects the direction of the magnetic field.

•Another that detects the strength of it.

The Pigeon Experiment

•Racing pigeons were placed above certain rocks that greatly effect the Earth’s magnetic field.

•Once the experiment was finished, 59 of the 92 pigeons flew way off course (4 km or more).

•Proved that magnetoreception does exist and greatly effects birds migrations.

The Pigeon Experiment #2

•Studies show that they don’t only rely completely on senses magnetic fields.

•Examinations of pigeon brains show that they create complex maps.

•Most likely created by using the magnetic sense and other visual cues from their surroundings.

Electromagnetic Induction

•Needs a conducting bar and a highly conductive medium

•Effects sharks, sting rays, etc.

•The Lorenzini (conducting bar) and the water help the animals senses the voltage drops from the Earth’s field.

•This helps with navigation.

Sources

• http://www.ncbi.nlm.nih.gov/pubmed/17069982?dopt=Abstract

• http://www.smso.net/Magnetoception

• http://neurophilosophy.wordpress.com/2007/02/16/homing-in-on-magnetoreception/

• http://www.biology.duke.edu/johnsenlab/pdfs/pubs/nrn%20review.pdf