…so, some more about those metatherians/marsupials.
In the previous part to this two part series, I went over some of the now-extinct metatherian megafauna that once graced Australia and South America. These animals were fantastic and marvelous pinnacles of metatherian specialization, yes, but there are plenty of surviving metatherians, all of them of the ‘marsupial’ clade, that are also largely ignored and their lives obscured. There are some truly bizarre and amazing marsupials outside of the traditional koala/kangaroo/wombat/possum group that essentially everyone on the planet associates with the marsupial infraclass, and all of them somehow survived invading hoardes of humans and other placental species (although, in most cases, just barely).
Powered flight (in the biological world, flight that comes from the mechanical flapping of wings as opposed to passive drifting or gliding) can be found in a wide range of animals on our planet. It is has evolved independently in insects multiple times, leading to a biologically diverse menagerie of colorful blotches on our windshields. While insects are far and away the first creatures to master the air (by a solid 200 million years), and the only invertebrates to do so, they share the skies with the much larger vertebrate fliers like birds, bats, and at one time, the reptilian pterosaurs. Aerial locomotion provides an animal with obvious advantages; ease in avoiding predators, access to new habitats and food sources, and the nullification of the game of Monkey in the Middle. There definitely are interesting correlations concerning the success of flying; it appears as though once evolved, flight is an incredibly successful strategy. Bats account for a fifth of all mammal species, birds have the most species of any land-lubbing vertebrate class, and the class containing insects is more speciose than all other animal groups combined. So it obviously pays to take to the skies, on a numbers and diversity level. That, and flying is quite clearly the most badass way to get around.
And yet, some representatives of these flying lineages drop the practice altogether. One explanation is that they are ungrateful, arrogant pricks who wouldn’t know the value of an honest day’s wingbeat if it bit them in the ass.
“Soaring elegantly through the heavens is sooooo mainstream.”