Is it possible for an organic species to generate a steady magnetic field?
The human body cannot rid itself of extra iron. Over time, these
excesses build up in major organs such as the heart, liver, pancreas,
joints, and pituitary.
Iron is ferromagnetic in it's metalic elemental state
is the basic mechanism by which certain materials (such as iron or iron oxides) form
permanent magnets, or are attracted to magnets.
Skin color changes (normaly noted as hyperpigmentation in the condition): Deposits of iron (compounds) in skin cells can make your skin
appear bronze or gray in color.
But can magnets lose their attraction? Yes, but:
it is metastable, and can persist for long periods, as shown by
samples of magnetite from the sea floor which have maintained their
magnetization for millions of years.
As far as I can find, there is no current example of a magnetised organism (or organism which emits no electromagnetism) existing. But if somehow hemochromatosis, and increased skin pigments of magnetic material were to be advantageous to survival and reproductive success, then yes, it would be possible that such an organism could evolve, over sufficient time.