Wednesday, 20 February 2013

Weird and Wonderful: Tachyglossus - The Real Easter Bunny

Ione Bingley

Rumor has it that a bouncing bunny bestows his tasty eggs upon hoards of hungry young humans. Call me a cynic, but where is this reputed Lenten rabbit getting his endless supply of eggs? Surely Thumper must be Big Bird in disguise, everyone knows mammals never lay eggs…or do they?!

This time friends we are heading out for a jaunt down under, under down under, to the Australian undergrowth, where a certain prickly customer snuffles out his creepy crawly quarry. This spiny insectivore may look to the untrained eye like our familiar British bonfire-lover, but we must remember, looks aren't everything. I have the pleasure of introducing you to the Echidna (eh-kid-na), and though she doesn't like to show her face, preferring you to ponder her spiny rear-end, I promise she is most fascinating indeed.

The echidna is larger than the European hedgehog and if you’re lucky enough to glimpse its cigar-like snout you will see it’s actually rather different in structure. With no hinge and a lower jaw that is reduced to a couple of bumps the echidna is already rather peculiar, and this is before mentioning its penis that has 4 openings! Like any other member of the Mammalia class, the echidna is warm blooded, suckles its young and has fur, albeit hardened into spines. However, unlike any other mammals, apart from their sole compatriot of the Monotreme contingent, the duck-billed platypus, Mrs Echidna lays eggs! 

The echidna is not some kind of bird-mammal Frankenmonster. It may actually elucidate the evolutionary link between the mammal-like reptiles (therapsids) and our furry friends of today, including Homo sap himself. The echidna lays eggs, has reptile like shoulder bones, a venomous spur, doesn't pant or sweat and, though warm-blooded, has a body temperature of 31-33°C, the lowest functioning temperature of any of our Mammalian brothers; could the echidna be warming up from a reptilian state?

Winter is the time for lonely hearts in the land of the echidna with up to 11 males following one female in a love train seeking her affection. One egg is laid every 3 years and the baby echidna hatches, after 10 days of eggdom, a mere 0.3g with closed nostrils. It is so altricial that gas exchange occurs directly across the skin surface. Unlike kangaroos and wombats, there is no pouch for the babies to hide in; they have to cling on for dear life with their tiny front feet with the mothers’ belly skin forming a ‘pseudopouch’ for support. 120 miniscule pores exude milk for the teeny echidnas hat becomes progressively thicker and more nutritious. After 5 or 6 days the nostrils open and after 35 days the babes are covered in peach-like fuzz. By 50 days it’s ‘on your own two feet chid’ and the mother digs a nursery burrow up to 2m long returning for only 2 hours every 5 days. The ‘puggles’ as they are affectionately known at this teenage stage, are able to consume up to 30% of their body weight in one feed, blowing up like a balloon. That milk must be real nutritious stuff because after seven months they’re off, the adventurous young’uns, travelling up to 40km.      

It’s no wonder we’ve never seen the famed Easter Bunny, we’ve been looking in all the wrong places. Why do you think he always hides his eggs in the undergrowth? Check out the video below.