Most male fin and blue whales sing at around 17 to 18 hertz, which is too deep for humans to hear, but the 'lonely' whale communicates at 52 hertz. When more recordings were released in the nineties, Dr Watkins studied the 52 hertz whale more closely.
The average person needs to absorb just a small amount of iron each day to stay healthy (around 1 mg for adult males and 1.5 mg for menstruating females). To achieve this, however, we need to consume several times that amount. This is because our bodies absorb only a fraction of the iron contained in the foods we eat.
How much iron do I need during pregnancy? As soon as your pregnancy begins, your body's iron requirement increases by 50 percent, from 18 milligrams a day to 27 mg a day. And once you give birth, you will still need additional iron; experts recommend 9 mg a day for nursing mothers.