Working in a biology lab is great fun. Although there are many rules to work with vertebrate animals, each standard has been thought through very carefully to consider the ethics of each action. In a mouse lab, we take very good care of the mice, making sure that their bellies are full of food, that any pain they experience is minimal, and that they can enjoy the company of mice of the opposite sex (or same, whatever fills their balloon).
Well, a new male was born in my old lab that seems to have all the female mice crowding just to get a better look ... ok, even the male mice (especially some fabulous ones) are also clamoring to glimpse this biological phenomenon. After years of working in a lab, I have seen mice born with extra toes, extra fingers, split tails, six legs, testicles with tumors that take up the entire peritoneal body cavity, massive spleens, and even two heads. But even *I* had never seen this before.
Males used for breeding purposes in a mouse colony are called 'studs'. This little guy brings a whole new meaning to that word - I'm sure he will be able to fulfill his post well:
Sorry I don't have a control picture to place beside this one to clarify for anyone who is unfamiliar with mouse work. For those of you who may not get it, this male has quite a massive phallus - in fact, it's close to an order of magnitude longer than a normal mouse phallus at his age (~7-10 days old). See the big pendulous member between his hind legs? That's not a double tail, that's his lady-pleaser.
Well, we'll see what the ladies think. I'm hoping he will be used for breeding purposes if possible, but if the mechanics don't look like a good prospect, well, he'll have to live with a bunch of males ... maybe there'll be a cohort in his cage that will be happy about that.