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.
The recommended daily intake for elemental iron varies depending on gender and age, ranging from 8mg/day to 18mg/day (27mg/day during pregnancy). The higher range of intake may be difficult to maintain, especially for vegetarians, who need to take in more iron because less is absorbed from nonmeat sources.