Evolution in Action
A recent study on evolution is shining the spotlight on the three-toed Australian skink. When it comes to reproducing, some skinks are foregoing egg laying by giving birth to live youngs. Apparently, lizards living in the warm lowlands of New South Wales (NSW) are literally putting all their eggs in one basket, while their colder mountain dwelling neighbours are favouring live births. Various species of reptiles were known to have made such transitions in the past. Not often do you catch them in action however.
What are the pros and cons of each reproduction method? Egg laying is a less taxing feat on the mother as she does not have to carry embryos. The caveat is a tantalizingly high mortality rate. As for live births, the fetus has a shelter for development at the expense of the mother.
This is certainly an interesting discovery, especially when the lizards are literally living in my backyard here in NSW!