Figure 5. Intensity B of the magnetic field, expressed in µT, induced in various parts of a green turtle's brain by a cylindrical magnet placed horizontally 6.5 cm above the head.

The values were computed as B = 0.1 m (3cos²(δ)+1)^0.5/d ³ where m = 0.015 A.m² is the magnetic moment of the cylindrical magnet, d is the distance from the magnet expressed in meters, and δ is the angular deviation from the cylinder axis (colatitude). The drawing of the turtle's head and brain was adapted from Fig. 172 in [25].