Help please settle a bet

David Robertson david.robertson at zetnet.co.uk
Sun Dec 3 13:38:24 EST 1995


In message <skohan-3011950039420001 at ts4-1.wla.ts.ucla.edu>
        skohan at ucla.edu (Sami Kohan) writes: 

> My friend and I argueing over the definition of a male. I claim that in
> sexually reproducing species, males do not ever bear young and she claims
> that there are instances where they do. She claims that for examples
> seahorse do, but I claim anyting that bears young, unless it is asexual,
> is by definition a female. Anyone want to settle this? Thanks.... I've got
> a dinner riding on it.

Lincoln, Boxshall & Clark in "A dictionary of ecology, evolution and 
systematics" define a male as "the sperm producing form of a bisexual 
or dioecious organism".  In other words, if it produces sperm it's 
male, if it produces eggs it's female.

The answer to your argument will depend on what you mean by "bear young".
If you mean that males do not ever incubate and raise young then you 
will be paying for dinner!  Your friends example of the seahorse is 
only the tip of the proverbial iceberg - there are several species of 
polyandrous birds, for example phalaropes, where the female will lay 
eggs then leave the male to incubate them while she courts another 
male and lays another clutch.  After incubating the eggs, the male 
has to raise, brood and protect the chicks single-handed until they 
fledge.  The female lays the eggs, and does nothing more - and a 
newly laid *egg* cannot be considered to be the same as *young*.
Also, in several amphibian species eggs are carried and incubated by the male.

Alternatively, if you mean the actual giving birth to *young*, then 
enjoy your dinner!  I know of no examples of viviparous species where 
*unfertilised* eggs are passed to the male .

When all is said and argued, you'll probably end up going Dutch on this one!





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