The Daily Mail had this little snippet news item for no apparent reason except oddness…
The fish that can survive for months in a tree
…discussing the ‘killifish’, as if that said enough. Not so. As Wikipedia explains a killifish can be anyone of over 1200 species of fish – the name is from Dutch and means ‘puddle fish’. However only one ‘killifish’ is able to self-fertilise – the only known vertebrate that does so – and that’s the Mangrove Rivulus. Oddly they are either male or hermaphroditic – there are no females.
Kind of reminds me of Cordwainer Smith‘s tale in which a human colony on a far-flung world suffers a horrible death that only targets women. By injecting male hormones to keep alive the last woman, a doctor, allows the colony to survive by enabling men to become pregnant. Thus all the couples on that world are homosexual, give birth via caesarean, and fight sword-fights for their lovers. But their psychology suffers and they become something not quite human anymore. Yet if we were fish we could change sex depending on our size and age, or even our birth temperature.
What we find un-natural, Nature has a way of giving us even more extreme examples.
