Jurassic Jukebox

Jurassic Jukebox

I found the topic in question so romantic, even poetic, I succumbed to framing my observation more as a "you-are-there" narrative and less a purely academic speculation. The subject addressed is, I believe, provocative, fascinating, and too infrequently examined, if ever to this degree.

Were the forests and jungles of prehistoric times, namely the Jurassic and Cretaceous, filled with a cacophonous din of animal sounds, calls, and songs? Or was there a general quietude only occasionally punctuated by the purposeful voices, here or there, of one creature or another?

Modern birds are a noisy lot. Everywhere, whether downtown in a bustling city or strolling about a pastoral woodland setting, we humans are surrounded by sounds both subtle and sublime, as birds of all sizes, shapes, and dispositions chatter among themselves.

Who of us has not at one time or another, listened to the melodious song of a bird, often unseen, as it throats some kind of message into the morning or early evening air? When populations are plentiful and varieties of species abundant, the listener is often bombarded by all manner of chirping, peeping, warbling, cawing, screeching and whooping and honking. It's an experience most of us take for granted. We rarely spend more than a moment or two (if that much) in serious contemplation as to the source from whence such sounds, so pure and elegant (sometimes not), should originate.

Exactly where and when did the ancestors of birds, both common and exotic, take their voice and music lessons? And from whom were they learned? Fortunately we know part of the answer. Generally speaking, modern-day birds evolved from dinosaurs and mostly from predatory raptors at that. Most dinosaurs were small, being largely overshadowed by the popular, but fewer-in-number behemoths with which most of us are familiar.

It does not necessarily follow, because a majority of today's birds are loud, talkative, and full of song, that their dinosaur ancestors genetically shared and imparted a proclivity for similar whoops and hollers. Birds live mainly in trees and, of course, possess a highly developed ability to fly, to navigate Earthly skies, and migrate to all corners of the globe.

The origin of flight itself is well beyond the scope or intent of this minor essay. More to the point is the fascinating question of whether birds evolved their intricate array of sounds, plus the desire to utter them, independent of their dinosaur ancestry. Or as seems far more probable, inherited both the attitude and aptitude for audibility from those same prehistoric predecessors.

The need for safety within a forest or under the jungle canopy should not be underestimated. We certainly believe such a lifestyle played a critical role in human evolution. The gabby birds who today nest atop high branches, may indeed have ancient and traceable, flightless relatives who could ill afford to announce their vulnerable presence to every predator within earshot.

Predators can themselves be the prey of mightier, fiercer carnivores. In a whole world of numberless predators and prey, a line is not easily drawn that separates one from the other. If we imagine a somewhat stereotypical, but not altogether inaccurate image of a prehistoric jungle or forest, only insects sport true wings and travel the airways. Except for certain winged cousins (pteranodons) who soar among the clouds, flightless dinosaurs -- both predators and prey alike -- are forced to scurry, run, jump, waddle, or plod their way along. But did they do so audibly, belting out every conceivable octave and pitch and tone? Did they announce to everyone within range, their noisy presence? Or in a situation where at any moment, fangs and claws might leap from behind the nearest bush or tree, was it better, safer, if you tended to keep your mouth, beak, or jaws shut?

All the fine camouflage in the world, the whole idea of blending in with your surroundings, might amount to nothing if you went about sounding like an air horn. So which was it? Could we have heard a tree fall in the forest because no one peeped a warble, or was the air choked with overlapping cries and exclamations of every range and frequency? Among Emperor penguins who congregate by the thousands while raising their young, it is thought that parents and offspring -- when separated -- can recognize and identify their unique "cries" from the thousands of other voices filling the cold, polar air. In like fashion, was the prehistoric wilderness a deafening jumble of ten-thousand different calls and cries, where parents constantly monitored the location and condition of their chicks and fledglings -- via their own unique sounds? And if so, what a wondrously noisy place that must have been.

As opposed to a cautionary need for silence, it may well have been the case that a forest (or elsewhere) brimming with the loud exclamations of hundreds of different animals, all belting out their own tunes, should have possessed its own defense mechanism, by which predators could become easily confused by the myriad sounds that surrounded them -- that bombarded them from every direction. Carnivores with stereoscopic hearing would have necessarily learned what noises came from unreachable prey not worth their time, and which were nearby meals offering themselves up as "today's special".

Paleontologists know, by virtue of the fossil record, that the skulls of many dinosaurs contain nasal air chambers capable of producing loud and forceful outbursts. But did they, and how often dare they? Part of the solution, surely, is found amid matters of size and vulnerability. Any dinosaur big enough, with few enemies, could afford to roar their hearts out with little fear of drawing undue attention to themselves. Large predators, however, when hunting and not scavenging, would have undoubtedly exercised a more stealthy approach. Silence is, of course, a chief component of surprise.

So what was it? Were the woods routinely full of sound and fury, or were they mostly quiet as cat paws on soft sand? Among the wealth of new and ever updated documentaries about prehistoric life, dinosaurs in particular, we don't hear much (pun intended) about the overall decibel levels one might have heard emanating from among the trees, behind fronds and ferns, and within the deepest shadows of the forest understory.

Much is made over the physical appearance of the dinosaurs, their coloration and musculature. Yet little is mentioned or theorized, comparatively, as to the grand and glorious, perhaps thunderous tones that could have issued from multi-ton bodies, huge chests and lungs, plus heads (like giant resonating chambers) measuring one or more meters in length.

If the smallish birds of today, weighing mere grams, can pierce the air with calls covering acres, even kilometers of distance, how deep and powerful, shrill or blaring, might have been the voices of the great beasts of prehistory? The question also arises as regards single individuals versus small groups or large herds. Numbers of animals grouped together would have provided an additional margin of safety and just as Canada geese frequently "honk" as a clamorous flock, it's easy to imagine leaves falling and branches shaken loose by the deafening blasts of sound reverberating among the trees. Or fading among the open plains.

One can only marvel as to how awesome such auditory exaltations might have truly been. Or rather, how silent breezes were interrupted only rarely by the brief cry, screech or scream of some jungle resident eager to fade once more into a backdrop of lush, protective foliage.