Like lead or cadmium, mercury is a constituent element of the earth, a heavy metal. In pure form, it is known alternatively as “elemental” or “metallic” mercury (also expressed as Hg(0) or Hg0). Mercury is rarely found in nature as the pure, liquid metal, but rather within compounds and inorganic salts.
In sea horses, the males become pregnant. Their mating involves the female inserting her oviduct into the male’s brooding pouch. She does this several times for short intervals to avoid exhaustion. In between the female rests while the male contorts himself to try to get the eggs in place in his brood pouch.