A Copula sivickisi jellyfish Patrick Randall Creative Commons Attribution-Share Alike 4.0 International
Jellyfish and their relatives are famous for their painful and dangerous stings, which are delivered by special cells called cnidocytes. So readers may wince at the fact that two species of box jellyfish package cnidocytes with their sperm.
However, the cnidocytes are not there to cause harm. Instead, they use sharp barbs to anchor the sperm inside the female’s gonads.
Box jellyfish belong to a group called cnidarians, which also includes corals, all of which have cnidocytes. Most cnidarians just release sperm and eggs into the…
