Science is limited only by our imagination. An inspiring statement, but one that also contains a note of caution. By the same token, we can argue that the potential for scientific discovery is limited by our human experience.
Back in undergrad, I was introduced to the German term “umwelt”, often translated as “self-centered world”. An organism’s umwelt is the perceptual environment that it senses and experiences, and it is very important, for biologists especially, to understand that that experience is nothing like our own. We can try our best to imagine how a fly may see the world (as Ferenc Rofusz did in his whimsical animated film), but the actual experience of vision through compound eyes is near impossible to comprehend from our single-lensed perspective, let alone the rest of an insect’s sensory experience. Of course, some animals do share our camera eyes or other features of perception, and so some umwelts are easier for us to understand than others.
I’ll give you an example. Let’s pretend you’re a behavioral neurobiologist designing an experiment. Maybe you are particularly interested in how dogs use their tails to communicate emotion, and you’re curious if there’s any asymmetry in the behavior – for example, if they tend to wag it more to one side than another when excited. So, let’s say you decide that your research question will be “Is tail-wagging in dogs a lateralized behavior?”
How do you go about answering this question? First, you’ll need to think of a way that you can reliably make a dog wag its tail. Hmm, how about the sight of its owner? Any dog would be excited to see their favorite person. How about a cat? That’s bound to get their tail moving! After you have selected your stimuli, then you’ll need to think about how to control all other variables (you don’t want the dog to be able to see you, for example). Well, you could probably construct a dog-sized box that blocks their vision of anything but what’s presented in front of them…and if you add some video cameras to the top, you can track tail movement easily enough. Great. All you need is a few dogs, and you’re all set.
That wasn’t so hard. Now let’s take the same question and ask it of a different species: is tail-wagging in geckos a lateralized behavior? Here is where your display of scientific prowess falters. How do you reliably make a gecko wag its tail? Do you even really know why geckos display this behavior? Is it related to emotional state at all? As for the experimental setup itself, you’re probably going to have to worry about their visual field: gecko eyes are positioned laterally on their head, so they have a much narrower range of binocular vision than dogs or humans. But you’re assuming that a visual stimulus will even elicit this behavior…maybe it’s only in response to a sound, or a smell, or temperature! It looks like you’ve got some serious homework to do, with no guarantee that all of your questions have been answered in existing literature.
If we want to study dogs, it’s a piece of cake. We ask, “Do dogs wave their tails differently based on their emotional state?” (they do), and after a quick brainstorm, we’ve already built the foundations of a feasible experiment. Geckos are more difficult to study in comparison. And this isn’t surprising: dogs were the first animal to ever be domesticated, and for more than 15,000 years they have been evolving side-by-side with humans. Our canine companions are arguably the easiest animal for us to understand.
We can’t help but be biased by our human frame of mind. Beyond just puppy love, we tend to exhibit a mammalian bias, vertebrate bias, bias towards “pretty” or “cute” species, etc. Say what you will, but you’re much more likely to empathize with the squirrel in your attic than the spider on your wall.
“So what?” you might ask. There’s no harm in having favorites…except when our bias permeates fields such as organismal biology. Sure, there are also plenty of reptile people, fish people, bug people, what-have-you people working with their species of choice, but it’s nowhere near an equal distribution. Our view of the biological world is shaped by what is studied, and so when the non-mammals, invertebrates, or simply less charismatic members of the animal kingdom get the short end of the stick, it has consequences.
One animal in particular that has suffered from this lack of scientific attention (you must have known it would come to this) is the domestic chicken.
Chickens are the most abundant domestic animal on the planet, clocking in at somewhere around 25 billion individuals. To provide some reference, the most abundant wild bird is the house sparrow, coming in at what comparatively feels like a meager 1.6 billion individuals (as of May 2021). Thanks to us, a staggering number of the birds on Earth cluck, cock-a-doodle-do, and cross the road to get to the other side. But, despite their overwhelming majority, chickens aren’t very well studied.
When I first got three hens of my own, I didn’t understand them at all. They didn’t act like any of the animals I was familiar with. For the first few weeks, I watched the birds explore their new home, chick fluff still visible around their necks and bald heads, and I worried. How could I be sure that they weren’t hungry, or too cold? What did those strained, croaking sounds mean? Were they supposed to move their heads like that? Would I even know a sick chicken if I saw one?
It was May 2020, so not only did I have plenty of unexpected free time, I also had a desperate desire to get my mind off of…everything. So, I sat and watched my pullets, familiarizing myself with their relatively alien behaviors. I did some online reading, and discovered the almost bottomless supply of backyard chicken blogs. I don’t think I would be exaggerating by saying that every question I had on raising chickens had an answer, and I was comforted by the cheerful anecdotes about handling Dotty the Wyandotte’s broody tendencies, or catching gapeworm early in Wilma the Buff Orpington. But I also worried about the reliability of this advice: if my chickens were open mouth breathing, should I really give them apple cider vinegar? Garlic? Drugs? [If you’re curious, I’ve found that apple cider vinegar serves as a boost to the immune system but won’t treat severe infection, garlic flavors the eggs, and a light dosing of anthelmintic is effective but can be harsh on an already harried system]. I cross-referenced advice between blogs, but it wasn’t enough. I wanted to be sure that I understood my little birds and their eccentricities. So, I bought a book called “The Behavioural Biology of Chickens”, by Christine Nicol. I started reading papers about chicken behavior and welfare. Almost all academic reading to be found on chickens is from a production standpoint: how do we get these animals to make more eggs? Can we make them grow faster? How do we fit more of them into a smaller space? Some of my most burning questions about chicken behavior were actually only answered by the blogs.
I found myself confronted with a Venn diagram of knowledge. On the academic side, I still had questions; on the blog side, I wasn’t sure I trusted every answer.
Why the gap in research? 25 billion domestic individuals, and I can’t find published results about treating anxiety in the wake of a predator attack? [If you find one, let me know!] A chicken’s behaviors and needs can be difficult to comprehend. What does their perceptual environment look like? How do they view the anthropogenic world they inhabit? Perhaps it is due to our mammalian bias that we haven’t yet answered these questions.
Chickens are in an especially tough position because they aren’t even always considered organisms. To most, they’re a commodity. Poultry meat production is expected to surpass 45 billion pounds in the US this year. And that’s just broilers. Laying hens have been producing at least 100 billion eggs per year in the US since 2016. At numbers like these, it starts to make sense why the common view of these birds is simply as a food product.
We are the ones responsible for creating this immense chicken population. It should be among our highest priorities to understand how these animals perceive their world so that we can improve their everyday welfare. And that requires a conscious effort to overcome our human bias, and to stretch our imaginations ever further.