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.
Iron Requirements. Adult women between the ages of 19 and 50 need 18 mg of iron each day, and men the same age require 8 mg, according to the recommendations of the Institute of Medicine's Food and Nutrition Board. The recommendation for both men and women 51 or older is only 8 mg.