For example, they say our ancestors' small canines mean they had touchy-feely sex lives:
Ardipithecus: We Meet At Last | The Loom | Discover Magazine
Those of you reading this post that have a Y chromosome have canine teeth that are about the same size as those of my XX readers. The same rule applies to the teeth of some other primate species. But in still other species, the males have much bigger canines than the females. The difference corresponds fairly well to the kind of social lives these primates have. Big canines are a sign of intense competition between males. Canine teeth in some primate species get honed into sharp daggers that males can use as weapons in battles for territory and for the opportunity to mate with females.
Men have stubby canines, which many scientists take as a sign that the competition between males became less intense in our hominid lineage. That was likely due to a shift in family life. Male chimpanzees compete with each other to mate with females, but they don’t help with the kids when they’re born. Humans form long-term bonds, with fathers helping mothers by, for example, getting more food for the kids to eat. There’s still male-male competition in our lineage, but it’s a lot less intense than in other species.
Which gives rise to the question of - if this is true - then what does that tell us about vampires?
Touchy-feely fellows vampires are not, but any survey of vampire literature would demonstrate they they have other uses for their canines besides hyper-macho contests for female vampires.
So let us drive a stake through all this overblown speculation about 4 million year old apeman sex - at least until we invent a time machine that would allow us to go back and observe things directly. All we have is one skeleton and a few other remains. Which by itself is fascinating, but which by itself tells us little.
* For those of you who do not follow these things, nowadays "brontosaurus" is called "apatosaurus" for some reason; and, no, birds are apparently not descended from them.