“We found evidence that dinosaurs sat on their nests,” he said. “We were able to show that. Dinosaur feathers—we were able to show that. In our lab we tend to be incredibly careful about what we say about this stuff . . . but no one has ever been able to come up with a total case for dinosaur cannibalism, like a member of the same species that’s inside the body cavity. Like Coelophysis was supposed to be.”
In a telling side story, Raymond Rogers provided another example of just how attractive the word cannibalism is to the media. “I took this story of dinosaur cannibalism to the Society of Vertebrate Paleontology meetings, and I called it “Conspecific Scavenging,” which is what I think it is. I remember that a guy from Science News looked at it, but nobody else really took much notice at all. I went home and thought about it, and I was like, ‘You know, why don’t I just call it cannibalism?’ So I did . . . and after that the story got in Nature and it was on the front page of Google News for about a week.”
“Well there you go,” I responded with a laugh. “That word does set something off in us.”
“Right,” Rogers agreed. “Before I knew it, USA Today was talking about dinosaurs, chianti, and fava beans.”
7: File Under: Weird
Cannibalism is found in over 1,500 species. Anthropophagusphobia (fear of cannibals) is found in only one. Which seems unnatural now?
— Author unknown
Is eating one’s own fingernails or mucus an example of auto-cannibalism? And what about breast-feeding? Is this type of parental care actually a form of cannibalism? Raymond Rogers considers scavenging the body of a conspecific dinosaur a form of cannibalism. Mark Norell, not so much. All are examples of a gray area between what most people consider cannibalism and other forms of behavior.
Like breast-feeding, the following example is a form of parental care, but one that extends further into the realm of cannibalism-related behavior. It occurs in the caecilians, a small order of not-very-obvious amphibians, whose legless bodies often get them mistaken for worms or snakes. Caecilians inhabit tropical regions of Central and South America, Africa, and Southern Asia—a neat trick that definitely lends support to the theory of continental drift. Although some caecilians are aquatic, it is not believed that their ancestors were strong enough swimmers to cross the Atlantic Ocean. Instead, prehistoric caecilians were likely separated when the current continents of South America and Africa split apart between 100 and 130 million years ago.
Caecilians also serve as great examples of convergent evolution, in which unrelated organisms each evolve similar anatomical, physiological, or behavioral characteristics, because they inhabit similar environments. As a result of their subterranean lifestyles, caecilians share a number of anatomical similarities with moles and mole rats. In each, the eyes are either set deeply into the skulls or are covered by a thick layer of skin, and as a consequence they are nearly blind.
Caecilians also possess a pair of short “tentacles” located between their nostrils and eyes. These chemosensors enable the subterraneans to “taste” their environments without opening their mouths, as they burrow through the soil or leaf litter in search of insects and small vertebrates. Similar types of sensory structures can be seen in other burrowing creatures, most notably the aptly named star-nosed mole (Condylura cristata).
As a group, caecilians exhibit a fair degree of reproductive diversity (which will become an important aspect of their cannibal-related behavior). Approximately half of the 170 species are oviparous (egg layers), and hatchlings either resemble miniature versions of their parents or pass through a brief larval stage. Other species are viviparous, giving birth to tiny, helpless young.
All caecilians do share one characteristic unique to the amphibians: internal fertilization, and during this process, sperm is deposited into the female’s cloaca with the aid of a penis-like structure called a phallodeum. For the orifice-challenged, a reminder that in many vertebrates (like amphibians, birds, and reptiles), the cloaca is a single opening shared by the intestinal, reproductive, and urinary tracts.