In addition to the ability of the skin to quickly repair and replenish itself, the nutritional content of this material is yet another interesting feature in this bizarre form of parental care. Normally, the outermost epidermal layer, the stratum corneum, is composed of flattened and dead cells whose primary functions are protection and waterproofing. But when the researchers examined the skin of brooding female caecilians under the microscope, they noticed that the stratum corneum had undergone significant modification. Not only was the layer thicker, it was also heavily laden with fat-producing cells, which explained why the baby caecilians experienced significant increases in body length and mass during the weeklong observations. It also explained why mothers of newly hatched broods experienced a concurrent decrease in body mass of 14 percent. In short, dermatophagy is a great way to fatten up the kids, but for moms on the receiving end of their gruesome attentions, the price is steep.
Scientists now believe that the presence of dermatophagy in both South American and African oviparous species offers strong support for the hypothesis that these odd forms of maternal investment originally evolved in the egg-laying ancestor of all modern caecilian species. Consequently, when the first live-bearing caecilians evolved, their unborn young were already equipped with a set of fetal teeth, which took on a new function, allowing them to tear away and consume the lining of their mothers’ oviduct.
8: Neanderthals and the Guys in the Other Valley
Here is a pile of bones of primeval man and beast all mixed together, with no more damning evidence that the man ate the bears than that the bears ate the man—yet paleontology holds a coroner’s inquest in the fifth geologic period on an ‘unpleasantness’ which transpired in the quaternary, and calmly lays it on the MAN, and then adds to it what purports to be evidence of CANNIBALISM. I ask the candid reader, Does not this look like taking advantage of a gentleman who has been dead two million years.
— Mark Twain, Life As I Find It, 1871
In 1856, three years before publication of Charles Darwin’s On the Origin of Species, a worker at a limestone quarry near Düsseldorf, Germany, uncovered the bones of what he thought was a bear. He gave the fossils to an amateur paleontologist, who in turn showed them to Dr. Hermann Schaaffhausen, an anatomy professor at the University of Bonn. The bones included fragments from a pelvis as well as arm and leg bones. There was also a skullcap—the section of the cranium above the bridge of the nose. The anatomist immediately knew that while the bones were thick and strongly built, they had belonged to a human and not a bear. They were, though, unlike any human bones he had ever seen. Beyond the robust nature of the limbs and pelvis, the skullcap had a low, receding forehead and a prominent ridge running across the brow. These anatomical differences led him to conclude that these were the remains of a “primitive” human, “one of the wild races of Northern Europe.”
The next year, the men announced their discovery in a joint paper, but the excitement they hoped to generate never materialized. This was, after all, a scientific community that had yet to reject the concept that organisms had not changed since God created them only five thousand years earlier. It was no real surprise, then, when a leading pathologist of the day examined the bone fragments and pronounced them to be modern in origin, insisting that the differences in skeletal anatomy were pathological in nature, having been caused by rickets, a childhood bone disease. He blamed the specimen’s sloping forehead on a series of heavy blows to the head.
By the early 1860s, thanks to the publication of On the Origin of Species, there was increased interest in evolution, especially the topic of human origins. Now the concept of “change over time” was no longer alien, and in the newly minted Age of Industry, the idea of the survival of the fittest was not only palatable, it was profitable. By 1864, the rickets/head injury hypothesis had been overshadowed by the discovery of new specimens with identical differences in skeletal structure. Neanderthal Man became the first prehistoric human to be given its own name, a moniker derived from the Neander River Valley, where the presumed first fossils had been uncovered.11
Thrust into the scientific and public eye, Neanderthal Man became a Victorian era sensation. Scientists like Darwin’s contemporary and friend Thomas Huxley believed these particular remains were important because they established a fossil record for humans that supported Darwin’s newly published theory. With none of his friend’s famous restraint, Huxley announced that Homo sapiens had descended with modification from apelike ancestors, and the Neanderthals were just the proof he needed.
Huxley’s rationale was that, although Neanderthals shared many characteristics with modern humans, they also exhibited primitive traits, thus serving as physical evidence that humans, like other organisms, had evolved gradually and over a vast time frame. Neanderthals, he reasoned, were a part of Darwin’s branching evolutionary tree, with this particular branch leading to modern humans.