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Ordovician(by mirelai from Deviant Art)

In a long-ago post, Ferrebeekeeper wrote about the Ordovician–the age of mollusks–when big predatory cephalopods and gastropods overtopped nascent vertebrates as the apex predators of the world oceans.  Cephalopods are fiercely intelligent, incredibly fast, and astonishing at camouflage.  They can be infinitesimally small or remarkably large.  They can even be transparent.  However they don’t last well—they are squishy and even if they aren’t eaten they have very short lives.  One of the most vivid memories of my adolescence was watching cuttlefish hover and change colors and feed with bullet-fast grabber arms at the National Zoo.  The memory comes with a dark post-script.  I returned a few months later with friends, only to find that the cuttlefish had entered a bizarre unnatural senescence and were literally falling apart at the seams.  They do not die of old age in the ocean; something always eats them.

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But this is no longer the lovely Holocene with its oceans full of fish and skies full of birds.  We have entered the Anthropocene—an age of hot acid oceans filled with Japanese trawlers bent on catching every last fish in the sea by means of nets the size of Rhode Island.  Suddenly it is not so beneficial to be a big bony ancient fish with hard scales and sharp teeth.  The teleosts and the cartilaginous fish are being physically pulled out of the ocean by humans.  It takes them too long to reproduce and rebuild their numbers (even as national governments subsidize fishermen to build more and larger fishing boats).  The age of fish—which has lasted from the Devonian (420 million years ago) until now—is ending.  So a new scramble to exploit the great open niches in the seas is beginning.

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Unexpected life forms are flourishing.  The sea floors are filling up with lobsters, which have not been so prevalent in a long time.  Giant jellyfish are appearing in never-before-seen numbers.  However it is beginning to seem like the greatest beneficiaries may be the cephalopods. Mollusks with shells are having their own troubles–as the carbonic acid oceans eat at their calcium shells, but the octopus, squid, and cuttlefish have no such problems.  Not only are they well suited for tropical waters, they rcan also reproduce so fast that they can keep ahead of human’s bottomless appetite.  A single squid egg cluster can have millions of eggs inside.

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Cephalopods tend to be generalists—they eat all sorts of things including booming micro-invertebrates and jellyfish. They are clever enough and malleable enough to slip out of all sorts of hazards.  Their swift lives are a boon. Because they reproduce so quickly and prolifically, they evolve quickly too—a necessity in our 24 hour world (as all sorts of out-of-work journalists, lamp lighters, factory workers, and saddlemakers could tell you).  I wonder if in a few million years the waters will glow with great shoals of exotic tentacle beasts we have scarcely imagined.  Will there be fast marlin-type squids with rapiers on their mantles and huge whale-shark type octopuses skimming the phytoplankton with their own giant nets? Will the skies darken with flying squids and the sea floor change colors as tens of thousands of cuttlefish take the roles of reef fish and reef alike?

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Hawaiian bobtail squid (image from forums.furcadia.com)

It is possible.  The world is changing faster than we would like to admit—becoming something brand new—becoming something very old.

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Saint Patrick Expelling the Snakes

Just kidding—aside from zoos and the pet trade, Ireland actually famously has no snakes.  It is one the few snake-free large islands on Earth joined only by New Zealand, Iceland, Greenland, and Antarctica (well—everywhere far enough north or south is snake-free: the reptiles don’t really thrive in places where there is permafrost or truly cold winters).  Legend has it that it was Saint Patrick who drove the snakes out of Ireland.  Standing on a great hill he lifted up his crosier and focused divine energy upon the unlucky reptiles which then writhed en masse into the sea and never returned to the emerald island.

"Ssseriously, why are you doing thisss?"

It has always been a bit unclear to me why Saint Patrick would do such a thing. Ecoystems which undergo such catastrophic changes tend to go haywire with great alacrity!  Fortunately the story is entirely a myth.  If snakes ever lived in Ireland (and it doesn’t seem like they did), they were long gone by the time the first Christians showed up.  The real reason is even more interesting than the dramatic Moses-like power of Saint Patrick, but as with most actual answers it is also more complex.

Evidence suggests that snakes evolved 130 million years ago during the Cretaceous.  At the time Ireland was, um, underwater at the bottom of a warm chalky sea.  Early snakes slithered their way across landbridges, rafted to islands on washed away logs, and swam (like the sea snakes) from island to island but, during the Mesozoic, there was no Ireland for them to go to.

Europe in the Ice Age (the pale white area was under a huge sheet of ice)

When the Mesozoic era ended in the great ball of fire, the continents again shifted.  Snakes went through a substantial evolutionary period during the Miocene and the original python-like snakes evolved into many different forms.  These new varieties of snakes slithered into grasslands, deserts, forests, and oceans around the world, but they still could not get to Ireland (now above the waves) because a cold ocean was in their way.  Then the end of the Miocene brought an ice age.  To quote the National Zoo’s essay on “Why Ireland Has No Snakes”:

The most recent ice age began about three million years ago and continues into the present. Between warm periods like the current climate, glaciers have advanced and retreated more than 20 times, often completely blanketing Ireland with ice. Snakes, being cold-blooded animals, simply aren’t able to survive in areas where the ground is frozen year round. Ireland thawed out for the last time only 15,000 years ago.

So Ireland remains snake-free because of the world’s temperamental geology. The island was underwater or covered by ice during certain eras when the snakes might have arrived–geography has conspired against serpents coming to Eire and setting up shop.  The age of humans however has been marked by numerous introduced species cropping up everywhere.  I wonder how long Ireland will be snake free when a pet shop accident or crazy hobbyist could unleash a plague of serpents on the green island.  The fact that such a thing has yet to happen seems almost as miraculous as the original myth.

Although many people construe the whole story to be an allegory of Saint Patrick driving paganism and the old gods from Ireland (as seen here).

Musa acuminata flower

Musa acuminata is a species of herbaceous plant from Southeast Asia.  Actually it is a very remarkable herbaceous plant because (along with certain other members of the Musa genus), it is the largest herbaceous plant living today.  They are so large that some people call them trees—although they are not properly trees.  The plant’s aspect is disturbing—almost like something out of a horror movie.  A giant pseudostem sprouts rapidly from a fleshy underground corm embedded within the jungle earth. This pseudostem is a towering appendage made up of layer after layer of horny leaf sheaths. Giant leafs grow out from the top of it—some of them as long as a man.

Diagram of Musa acuminata

At the very top of the pseudostem sits the elaborate reproductive apparatus of the plant, a grotesque inflorescence made up of alternating rows of flowers and petal-like bracts.  The strange mass droops down from the tree and a wizened inferior ovary dangles at the bottom.  As the female flowers are fertilized they form a hanging cluster of distinctive fingerlike fruits.  These bulbous “fingers” are grouped in tiers and they angle upward giving the whole stem an alien look. The fruit of Musa acuminata is radioactive because it contains a large amount of potassium (including potassium-40).  Botanists have described the fruit as “leathery berries” (although, to my eye, the elongated fruits suggest something other than berries).

Musa acumniata inflorescence

Although the fruits have a stiff waxy covering and contain a great deal of potassium, they are sweet–so jungle animals carry the pods around, eat them, and distribute the seeds (although the plant also produces asexually by suckering off clonal buds).  Some animals are especially drawn to the fruits and scientists speculate about whether Musa acuminate evolved symbiotically with the primates of Southeast Asia.

In fact 10,000 years ago an invasive species of African primate which had somehow made it to Papua began to select varieties of Musa acuminate trees which suited their taste while destroying (or at least not propagating) the other varieties.  Soon the fruit began to change into something which fit the primates’ hands and suited the beings’ color palate.

Musa acuminata was hybridized with other Musa species (particularly Musa balbisiana) in order to create different varieties of fruits. Parthenocarpic varieties of bananas were discovered and the virgin plants were carefully nurtured and cloned. Ten thousand years of selective breeding has produced a big yellow glowing seedless fruit, far different from the little stunted green fruit. Archaeologists believe that the banana might have been the first domesticated fruit (the only other contender is the ancient fig—which did, in fact, evolve alongside African primates).  Today they live throughout the tropics and subtropics.  Banana plants are additionally used to make fiber and as ornamental plants, but their importance as a foodstuff for humankind is difficult to overstate.  Not only are the yellow “Cavendish” fruits eaten in immense quantities, but starchy plantains are consumed with savory meals, and banana wine is the dominant spirit of large swaths of Africa.  Bananas are the most popular fruit in the world and our fourth most abundant crop overall.

Cuban bananas wash ashore along a Dutch island off the North Sea after a shipping mishap

 

An Iridescent Wasp on a Linen Tablecloth

Today I would like to start a brand new animal category concerning the most gifted of the social insects, the superorder Hymenoptera, which consists of wasps, bees, ants and sawflies (along with some other oddballs which are less frequently mentioned).  Hymenoptera are arguably among the most successful creatures on the planet.  Their behavior can be almost embarrassingly humanlike and they are famous for building elaborate constructions, going to war, taking slaves, farming fungi, and crafting rigid city-like social hierarchies. However, of all life forms on earth, the hymenoptera are some of the most vividly alien: cuttlefish do seem downright cuddly when compared to the horrifying digger wasps.   A sociologist could happily draw parallels between a bee hive and a city until he looked at the details of bee reproduction, at which point he would probably break down and weep.

The Hymenoptera are not as ancient as either the mollusks or the mammals (if it is fair to compare an order with a phylum or a class).  They originated in the Triassic and did not develop the successful social organization which is now such a defining feature until the late Cretaceous.   The first hymenopterans were the xylidae, a family of sawflies with a minimal presence on earth today but with a long pedigree. These first sawflies fed on the pollen and buds of the conifer stands beneath which the first dinosaurs developed (and under the roots of which the first mammals cowered).  The rise of the flowering plants in the Cretaceous led to a leap-forward for these pollen-eaters: complex flowers then evolved in tandem with the hymenopterans. It was also during the Cretaceous that the ants and termites split from the vespoid wasps.  The earliest honey bees of the familiar genus Apis evolved at the end of the Eocene bt they were preceded by all sorts of hymenopteran pollinators.

A Sawfly Fossil (Hymenoptera: Symphyta)

I mentioned above that, for all of their familiarity to us, the Hymenoptera are disturbingly alien.  In fact as I have been writing this comparatively tame post, a dreadful sense of formication has stolen over me and I find myself brushing phantom ants from my limbs and feeling the terrible pang of yellowjacket stings from childhood.  The hymenoptera are frequently the basis of the extraterrestrial enemies in science fiction.  Although people are occasionally stung to death by wasps or ripped apart from within by driver ants, it is something larger and less tangible which makes the hymenoptera such reliable villains. I have watched the soldier bees snip the wings off of wasps trying to invade my grandfather’s bee hive and then toss the invaders’ writhing bodies from the painted ledge—all while a river of worker bees went out and came back laden with pollen.  There is an alarming touch of civilization to these social insects: a hint that they are utilizing the same kinds of organization and communication which have made humans such a success.  And, in fact, the social insects are a huge success—ants alone are estimated to constitute a substantial portion of the animal biomass of earth (to say nothing of termites, bees, wasps and the rest).

Yellow Jackets on a Coke Can (photo by the fearless Alan Cressler)

Of course this success has broad ramifications. The hymenoptera are everywhere in nature and they also play a huge part of human culture. Indeed the very name of this blog is a play on words between my surname and the noble art of aviculture.  Without the bees, we would not have much in the way of fruit or vegetables.  Not only would this be a disaster for human farming—just contemplate how many other creatures rely on those fruit!  Similarly the ants bulwark an entire portion of the ecosystem by scavenging the tidbits out of fields and forests.  Writing about the hymenoptera may be an itchy, antsy business but it is a well-merited study.  This group of insects is pivotal to life on dry-land as we know it.  The biblical promised land was one of milk and honey.  There would be no milk without mammals, but there would be no honey (and precious few mammals) without the hymenoptera.

A beekeeper completely covered with swarming honey bees in a “bee man” cantest in China

The Giant Armadillo (Priodontes maximus)

We boldly continue armor week with an overview of the magnificent armadillo family.  This order of armored mammals (Cingulata) is more diverse than any other sort of armored mammals–outshining even the scaled pangolins. Today the only living members of the Cingulata order are the armadillo family (a successful group consisting of more than 20 living species) but the armadillos’ extinct cousins were once far more widespread and bizarre.  These relatives included the pampatheres–long plantigrade browsing creatures covered in banded armor who roamed the continent from one end to the other.  Even more impressive were the glyptodonts, massive tank-like creatures bigger than a compact car.

A fossil glyptodon, fossil pamphathere, and armadillo skeleton (in the far right corner)

The Cingulata order is part of the superorder Xenarthra. Separated from all other placental mammals for over 100 million years (due to South America’s unique isolation after the breakup of the southern supercontinent Gondwana), xenarthrans evolved in different directions from other mammals. The unique challenges and opportunities of their island continent resulted in bony domed giants like the pampatheres and glyptodonts, both of which are characterized by tortoise-like body armor composed of bone segments (osteoderms).  The glyptodonts were unlike tortoises in that they could not draw their head beneath their shells: instead their heads were protected by bony caps atop their skulls. The largest glyptodonts could grow to 4 metres long, 1.5 metres high and have a mass of 3 tons (Ferrebeekeeper has already written about the smallest known Cingulata species—the pink fairy armadillo, which can still be found living in the central dry lands of Argentina).

Glyptodon

Thanks to convergent evolution the herbivorous glyptodonts resembled other armored giants like cryptodire turtles and ankylosaurs.  One species of glyptodont, Doedicurus clavicaudatus, even had a heavy spiked tail (although it is unclear whether this was used against predators or to compete for territory and mates).

Doedicurus clavicaudatus

When the first members of the Cingulata order emerged in the Myocene, the top predators of South America were giant running predatory birds–the Phorusrhacidae, which resembled giant dashing eagles up to 3.2 metres (10 ft) high.  The glyptodonts, pampatheres, and armadillos outlasted these terror birds and they then outlasted the carnivorous metatherian mammals (with terrible saber teeth) which followed.  When the Isthmus of Panama connected South America with North America (and therefore with an entirely new universe of ultra-competitive mammals), the armored cingulatans competed just fine with the newcomers.  Some glyptodonts and pamphatheres wandered up through Central America and found new homes in North America.  The armadillos are still there.  However at the end of the last ice-age, a new African species arrived and brought a devastating and final end to the glyptodonts, the pampatheres, and most of the armadillos. But even this newly arrived predator seemed impressed by the greatest of armored mammals.  An Argentine anthropologist even reports discovering a site twenty leagues from Buenos Aires where early human hunters had used glyptodont shells as dwelling places.

Human Hunters Stalk a Glyptodon (Heinrich Harder)

The Short-Beaked Echidna (Source: M McKelvey/P Rismiller/)

Last year featured an in-depth examination of Echidna, the terrifying “mother of monsters” from Greek mythology.  To start this year on a glorious high note, here is an essay concerning the actual echidnas (Tachyglossidae), a family of mammals from Australia and New Guinea.  The echidnas were much wronged when explorers named them after a hellish demigoddess.  Although I have never met—or even seen—a living echidna, they are one of my favorite creatures for many reasons.  Combining a gentle temperament with fascinatingly alien intelligence, the echidna is a delightful animal whose taxonomical oddity reveals the strange paths of fate which life takes over great expanses of time.

Along with the charismatic platypus, the echidna is the last of the egg-laying monotremes.  Monotremes are a very different sort of mammal than the other two major divisions of mammals, the eutheria and the metatheria.  The teeming eutheria (familiar mammals like shrews, manatees, picas, goats, and humans) nourish their fetal young by means of a placenta.  The ancient metatheria (marsupials) sustain their developing young in a special pouch.  The monotremes predate both groups and give evidence of mammals’ origins.  Genetic studies suggest that the monotremes originated from some reptile-like ancestor about 220 million years ago.  The long and tangled family history of the mammals and their antecedents will have to wait for another post–suffice to say that monotremes have been here for an extraordinarily long time.  The surviving monotremes, however, are not primitive atavists, but extraordinarily advanced descendants of those ancient progenitor mammals.  They have evolved and survived in varying fashions over the long eons.  Over those millions and millions of years, the echidna developed a very interesting brain.

Echidnas have the largest neocortex relative to bodymass of any creature.  The neocortex (which Hercule Poirot always creepily referred to as “the little grey cells”) is involved in higher brain functions such as spacial cognition, logic, and problem solving.  This special tool has taken the echidna far: like humans, and unlike almost all other creatures, echidnas live in very diverse habitats.  Actually it is the short-beaked echidna (Tachyglossus aculeatus) which lives in different habitats—the other two extant species live in tropical New Guinea and are little known to science.  Although all three species seem to share most traits, I am really writing solely about Tachyglossus aculeatus which ranges from the hot dry desert scrub, to the tropical rainforest, to the coast, to the cold snows of the Australian Alps (where they can lower their body temperature a few degrees above freezing and hibernate).  Echidnas live on termites and ants, omnipresent social insects which are evolutionary winners in their own right.  Echidnas dig up these insects with powerful razor claws and gobble them down using a long sticky tongue which zips in and out of a toothless tube-like mouth.  Echidnas are not known to fight each other or other animals.  In the great evolutionary battle they are pacifists (provided you are not an ant or termite) and if approached aggressively they will curl into a ball and trust their sharp spine-like hairs to keep them safe.  They are also phenomenal burrowers and can quickly tunnel down through anything other than solid stone.

An orphaned puggle being handraised.

Because of their cleverness, relatively little is known about echidnas.  They are difficult to capture since they disdain baits and can figure out most traps.  Similarly, in zoos, echidnas have proven extremely gifted at escape.  Their mating habits are largely mysterious to us but seem to involve non-confrontational competition.  The female echidna is followed for an extended period of time by a train of interested males.  In response to an unknown signal, the male echidnas begin frantically digging, trying to nudge one another out of the way.  Just how the victor emerges from this competition is unknown, but one the female has chosen, the other males walk away with no obvious rancor.  After laying her egg, the female immediately rolls it into a pouch-like fold on her abdomen.  Once the puggle has hatched, the mother echidna solicitously tends it for seven months, after which it roams off free and solitary.

Echidnas have an extra sense, electoreceptivity, but for them it is much weaker than it is in their close cousins the platypuses.  It has also been noted that echidnas vibrate. Water placed near captive echidnas shows distinct ripples in the surface. Perhaps they vocalize on frequencies beneath the range of human hearing (as do elephants).  Speaking of captivity, Echidnas have survived for up to 30 years in zoos even though it is a difficult environment for the blithesome free-roaming animals.  It is believed they live twice that long in the wild—but, again, nobody really knows.

Agh! Get away from there! I though you had a large neocortex!

Likewise nobody knows the echidnas’ total population numbers or how healthy the species is.  What is known is that, sadly, even the intelligent and peaceful echidnas are running into problems in the modern world.  Like other good-hearted pedestrians, echidnas are often killed by careless drivers.  Echidnas face increasing habitat destruction from human houses, farms, and roads.  Likewise they must deal with new predators, the dingos, which have discovered that urinating on balled-up echidnas will cause the latter to uncurl for a moment in stunned disgust (giving the ruthless dogs a chance to rip into their guts).

I wonder what echidnas think of us.  They know of our traps, our radio-tracking devices, and they know how to avoid aborigine hunters.  They are becoming wise to our deadly cars and to the dirty tricks of dingos.  Still they remain curious about people and will sometimes come out of the wilderness in groups to examine our suburbs and cities before melting back into the wild.  Humankind took a long while to understand that echidnas are not dim-witted reptilian pincushions but rather clever and highly developed generalists.  Do they generously think the same of us, or do they put humankind from their mind as something foul when they head back to the ancient, open outback?

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