Question: Why do male seas horses carry the babies xox

Leo Garcia answered on 25 Jun 2010:

Unlike in humans, it is the male which carries most of the burden of reproduction in sea horses. This begs the question of exactly why, in different species, one sex or the other takes the burden, particularly as, in general, it is usually the female of the species which puts more energy into reproduction than males. This is known as Bateman’s Principle:

http://en.wikipedia.org/wiki/Bateman's_principle

It depends upon the evolutionary history of the species, which determines how and where and when reproduction occurs. It comes under the heading of evolutionary biology, and if you wanted to work in that field, you could go here:

http://www.biology.ed.ac.uk/research/institutes/evolution/
http://evolve.zoo.ox.ac.uk/Evolve/Welcome.html
http://ecoevo.bio.uci.edu/

And many other research institutes!