“That doesn’t look very scary. More like a six-foot turkey.”

One of the things I enjoy saying the most about my experience with wildlife rehabilitation is that I have worked with raptors – birds of prey like owls, hawks, and falcons. They are amazing, interesting birds but I’ll admit that part of that fun is that when people hear “raptor” they often imagine this:

This association is probably partly due to the blockbuster “Jurassic Park” and other dinosaur movies. A major theme of the film, and one that I love as a student of evolutionary anthropology, is demonstration of the bird-dinosaur relationship. The species Compsognathus is described as walking chicken-like, and the final scene of Jurassic Park shows a flock of birds flying from Isla Nublar and the dinosaurs that dwell on it. After Dr. Alan Grant is laughed at for stating that dinosaurs obviously became birds, he retorts with this:

“Well, maybe dinosaurs have more in common with present-day birds than they do with reptiles. Look at the pubic bone: turned backward, just like a bird. Look at the vertebrae: full of airsacs and hollows, just like a bird. And even the word ‘raptor’ means ‘bird of prey.’”

However, this quote implies that there was foresight in the naming of both birds of prey and certain dinosaurs “raptors” because birds are the evolutionary descendants of some dinosaur species. But the way in which language evolves through translation and interpretation means one cannot assume that the naming intentional. And in terms of the history of the knowledge of evolution, this naming was actually more of a coincidence.

The word “raptor” comes from a Latin verb rapere “to seize by force”. Birds of prey are called raptors because of they way they hunt, seizing their prey out of the air, and Websters dictionary first defined birds of prey as raptors in 1823.

The term “velociraptor”, and other species containing the suffix -raptor, probably originated in scientific literature around 1924. They were so named because velox means “swift” and so velociraptors were thought to be speedy predators who seized their prey.

However, both of these groups received their designation as “raptor” long before paleontologists were able to link birds as the descendants of dinosaurs. The evidence of the bird-dinosaur evolutionary lineage was not concretely supported until the 1980s when dinosaur phylogeny was more fully understood with increasing knowledge of genetics, phylogeny, and evolution.

Assuming that the two share a name because they share an ancestor is a false cause logical fallacy, meaning that a false assumption is made when one believes a relationship seen between two things automatically implies one caused the other.  In fact birds of prey and some dinosaur species were named before their evolutionary relationship was understood and so their name was more a convenient coincidence of word choice.

If early orinthologists had decided that birds of prey didn’t seize their prey but rather grabbed, snatched, clasped, clutched, or caught them, the Latin translation never would have matched the dinosaur term that came later.

“Diets, like clothes, should be tailored to you”

Fad diets, as their name suggests, are easy-to-follow and trendy diets focused more on short-term success than long-term maintenance of health and weight. Focus is usually placed on eliminating or emphasizing a particular food group for health benefits.

However these diets tend to be difficult and sometimes even dangerous to follow for long periods of time. The Paleo Diet is considered by many to be a fad diet, which I why I was surprised that it is still a somewhat prevalent.

The Paleo Diet, short for Paleolithic Diet, is based on the diet of the early humans (called hominids) which lived during the Paleolithic era of 2.5 million years ago to 10 thousand years ago. It is believed to follow the general “ancestral human diet”.

It claims that humans are most adapted to the diet of their Paleolithic ancestors – fish, eggs, vegetables, fruits, roots, nuts, and wild game. Therefore sugars, salts, oils, and grains and vegetables which came about during the Agricultural Revolution are discouraged.

The claim of the Paleo Diet is that natural selection has not strongly acted on humans since the rise of agriculture, thus humans are maladjusted to the modern diets which they now consume. Hunter-gatherer societies, which still follow the basic ancestral human diets, have overall lower prevalence of disease.

By this reasoning, foods which humans are considered ill-adapted for are partly responsible for the increasing rates of obesity, cardiovascular disease, high blood pressure, Type 2 diabetes, and even cancer.  To help avoid the diseases caused by the “modern affluent diet”, humans should follow the Paleo Diet and avoid modern foods.

But, while abstaining from excesses of sugar and oil is beneficial to human health, the actual scientific reasoning behind the Paleo Diet is shaky at best.

1. Lifestyle is a major factor in any diet, not just the Paleo Diet

The lifestyle that the Paleo Diet promotes is itself healthy – growing or hunting one’s own food, and not eating in excess are healthy additions to any diet protocol.  The main bulk of the health advantages stemming not from what hunter-gatherer peoples actually eat, but how they live, and their diets are a result of their culture.

Basically, hunter-gatherers are more active and tend to consume fresher foods because they must acquire it for themselves.  Any modern American who hunts and gathers their own food will surely already lead a more active lifestyle and is also less likely to consume processed foods and junk food, whether or not they are following the textbook Paleo Diet.

However, the changes that have occurred among urban societies, even in the past century or so, have made following a hunter-gatherer lifestyle next-to-impossible.

2. The Paleo Diet assumes human evolution abruptly stopped at the rise of agriculture

The assumption that humans have not changed or adapted to their environment in the past 10,000 years ignores everything we know about evolutionary change. If adaptation comes naturally over time, why should change suddenly stop? While it is true that natural selection may be acting less on populations now with modern medicine and more consistent food sources, but fluctuations in population genetics are always present.

Furthermore, there is evidence that rapid changes have occurred in human populations since the rise of agriculture, and the evolution of lactose tolerance is a good example. A few thousand years ago there was an increased interest in animal husbandry in human populations, which led to more access to dairy products like cheese and milk. Early humans naturally lost lactose tolerance after weaning, but populations with access to dairy have since evolved a genetic ability to continue to digest lactose into adulthood and therfore retain the ability to acquire nourishment from dairy products.

3. Humans are opportunistic omnivores and are designed to eat a variety of diets

The premise of the Paleo Diet is that humans are specifically adapted to a certain diet and are maladjusted to consuming different diets, which has already been proven false by the evidence of change in lactose tolerance. Furthermore, this assumes that all early human groups ate the same diet, which is wildly blind to the fact that human populations arose all over the world and couldn’t possibly have eaten the same foods. And anthropologists can never be sure of the exact diet of any ancient group because it would have been widely variable based on location, season, and food availability.

Furthermore, the fact that humans only had access to certain foods during their evolutionary history doesn’t automatically mean that they aren’t capable of eating other things.

4. Diet alone cannot guarantee health

There is no specific relationship between genotype (one’s genes) and phenotype (one’s physical traits), so even if humans were specifically adapted for a certain diet, genes are not the only factors which influence final health, and environment and early development can have equally strong impacts later in life.  Hormones, musculature, and metabolism, among other factors, mean that some people will naturally weigh more or less no matter the diet they follow.

So, while the reasoning and science behind the Paleo Diet seems inaccurate at best, this isn’t to say that it can’t be beneficial to one’s health to follow some of the suggestions it makes. However, strictly following the Paleo Diet based on the belief that you are eating as ancestral humans did won’t be anymore beneficial than any other fad diet out there.

“Food for thought”

I am currently in an anthropology class that focuses on how food perspectives, nutrition, and diets have shaped human evolution. It focuses on what we eat and why, and the cultural impacts of these beliefs. Naturally, the phrase “tastes like chicken” came into the discussion on day #1 and it piqued my curiosity about the origins of the phrase and whether it was actually true.

Fried Chicken

First off, the origins of the phrase seem to come from the late 19th century, when a European writer described eating a rat in China as having the consistency, texture, and taste of chicken. Since then, it has become a common, often comedic phrase, used to describe a variety of foods – sometimes describing things that actually taste like chicken, or something that is bland, or something that is exotic or strange.

My first instinct on the possible accuracy of this phrase, being an evolutionary anthropologist, was that perhaps all of the animals that supposedly taste like chicken originated from one common ancestor that tasted like chicken, or more accurately all things that taste like chicken actually taste like this common ancestor.

The flavor of meat can be based on the evolutionary origin of the animal, due to chemical make-up of the animal’s muscle tissues and other factors that influence taste. As it turns out, species descended from tetrapods tend to taste like chicken – i.e. birds and reptiles. Hoofed animals diverged from the tetrapod lineage, explaining why they have a different flavor than the rest of the animals we eat.

This is a phylogenetic tree, or visual representation of evolutionary history, of the species of animals that reportedly taste like chicken.  Note the divergence of the hoofed animals and the differing flavors of their descendants.

This is a phylogenetic tree, or visual representation of evolutionary history, of the species of animals that reportedly taste like chicken. Note the divergence of the hoofed animals and the differing flavors of their descendants.

This brings up the fun theory that because dinosaurs were the evolutionary predecessors of birds, they probably tasted like chicken too.

Tastes like Chicken

Of course, my explanation of the evolutionary theory of chicken flavor was promptly shot down by a friend majoring in biochemistry (you know who you are, buzzkill). He declared that the real reason that some things taste like other things is their glutamate content.

Flavors in meat are partially due to glutamate, an amino acid derivative that seems to contribute to the “savory” flavor of meats. Research shows that chicken has a lower glutamate content than many other meats, which results in the bland flavor that chicken can have, making it a more universally-comparable flavor.

While I agree with his explanation, I disagree with his disagreement of my theory. If studying anthropology has taught me anything, its that there is never just one simple answer to anything. So often, especially in the field of evolutionary biology or evolutionary anthropology, people are quick to judge one theory as being wrong or against their beliefs. But the important thing to remember about evolution is that it is not mutually exclusive of any other fact – instead it works with these facts to help explain how and why they came about.

Which leads me to the last point about this whole article – anything I have said here does not actually make much sense because different subspecies of chicken, age of chicken, cut of chicken, flavoring, cooking method, etc. can all have huge influences on flavor so there is really no way to say that something tastes like chicken when there is really no definitive “chicken flavor”. It’s all really just fun food for thought.

Even foods that say they taste like chicken don't really taste like I imagine chicken to be.

Even foods that say they taste like chicken don’t really taste like I imagine chicken to be.