WHAT DO ’POSSUMS HAVE IN COMMON WITH ’ROOS? WOMBATS AND KOALAS TOO. 

INDEED, THE WEBSITE INTERESTING FACTS is aptly named: “A Newborn Kangaroo,” it says, “is MUCH Smaller Than You Realize.” Well, I must confess my realization skills in this regard have been lamentably weak, but I get the point. Do tell me more. 

In fact, after reading this Daily Fact, August 25, 2023, and a little Internet sleuthing, I came up with today’s title above. Tidbits follow, together with a couple of personal notes. 

They’re All Marsupials. Female kangaroos, koalas, opossums, and wombats all have pouches for their offspring. Merriam-Webster says “ ‘marsupial’ comes from New Latin marsūpium, going back to Latin marsuppium, marsīpium ‘pouch, bag,’ borrowed from Greek marsíppion, marsýppion, from mársippos, mársipos, mársypos, mársyppos ‘bag, pouch.’ ”

Live birth occurs in a fetal stage, in the kangaroo less than an inch long. The roo mom leaves a scented trace so the joey (as marsupial kids are known) can maneuver into her abdominal pouch equipped with milk-providing teats. 

With roos, the joey resides there for perhaps two months, then begins venturing out periodically, confident in scampering back into the pouch until weaning is concluded. 

Pouched Moms. I had known about kangaroo pouches, but hadn’t realized that other Australian critters have them too: Koalas, wombats, Tasmanian devils, and bandicoots are also marsupials. And so are opposums, which Wikipedia notes, are the largest order of marsupials in the Western Hemisphere…. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America.” 

 How’s that? Wasn’t Central America always there as a bridge between the two? 

Not Before the Volcanic Isthmus. Prior to some 3 million years ago, North and South Americas had very little interchange of flora or fauna. 

Yet, Wikipedia notes, “The relationships among the three extant divisions of mammals (monotremes, marsupials, and placentals) were long a matter of debate among taxonomists.… In 2022 a study provided strong evidence that the earliest known marsupial was Deltatheridium known from specimens from the Campanian age of the Late Cretaceous [100.5–66 mya] in Mongolia. This study placed both Deltatheridium and Pucadelphys as sister taxa to the modern large American opossums.”

Above, a North American opossum, Didelphis virgininana, displaying its winter coat. Image by Cody Pope from Wikipedia. Below, Pogo Possum, Walt Kelly’s cartoon pal, 1948–1975. Image from City Journal.

“Marsupials reached Australia via Antarctica during the Early Eocene, around 50 mya, shortly after Australia had split off,” Wikipedia notes. 

Evolutionary Happenings. If I’ve got this right, the earliest marsupials arose in what’s now Mongolia in Central Asia. Apparently they traveled to North America across the Bering Bridge along with lots of others (including the earliest Native Americans). While some of these marsupials died off, others headed south across the isthmus. 

Then, possibly, some of these marsupials got to Antarctica and, eventually, Australia. Or maybe they moved south from Mongolia to Wallacea and Australasia.

Personal Notes. I recall that Peter “Possum” Bourne was a national hero in New Zealand as rallyist driving Subarus, especially the Impreza WRX.

Alas, Possum died in a 2003 pre-rally recon on the Waiorau Snow Farm Road. 

I know this locale near Wanaka, New Zealand, from my own winter tire testing there in August 1999 (See R&T, December 1999).

Wife Dottie’s experience was distinctly different. One evening whilst I was off tripping somewhere or other, she heard our Husky/Malamute Kenwood raising a racket in the back yard. She investigated, albeit leaving her glasses on the bedstand. 

She related the tale: “There was Cappy up on the fence. I reached up and said, ‘You get down! Bad kitty!’ ”

Then the opossum snarled and showed distinctly unfeline dental hardware. 

We hadn’t realized at the time we had an occasional marsupial in our back yard, but I do now. ds 

© Dennis Simanaitis, SimanaitisSays.com, 2023