You’re more likely to make friends with a cow than a moose

[This post refers to a whole bunch of published studies – I’ll provide links to them in the text so you can check them out yourself!]

Domestication, the process that turned wolves into dogs, guanacos into llamas, ducks into…well, domestic ducks, comprises changes that help a species thrive in a captive, human environment. We use labels such as “artificial selection” or “selective breeding”, implying that humans were the agents of change in this process. However, we have yet to fully understand all the mechanisms of domestication.

There is a famous study that illustrates just how much we have to learn: in the mid-20th century, Dmitri Belyaev began selecting silver foxes based on “tameness” alone, breeding only the foxes with reduced or no fear of their human caretakers. Within only a handful of generations, Belyaev’s fox population underwent a drastic transformation: they developed floppy ears, spotted coats and curly tails. They began to look a lot like puppies…or actually, like most domestic mammals. Goats and sheep also have long floppy ears, cows are known for their spots, and pigs for their curly tails. These traits commonly arise in domesticated species, without intentional selection by humans.

This “domestication syndrome” reveals that there is much more going on during domestication than human selection alone. We have much to learn about the inheritance of such traits, and not only the physiological ones: changes in behavior, such as in sociality, are also linked to the domestication process. Such behavioral changes allow domestic animals to cooperate and communicate with their human caretakers more effectively. In ecology, a coexistence that benefits both species is known generally as mutualism. In ethology, we call this specific type of mutualism the human-animal relationship.

Consider our best friends. Dogs possess certain behavioral adaptations that make them ideal human companions. One striking example is “looking behavior”. When presented with what appears to be an impossible problem, dogs will look to a human for help, seeking eye contact. Wolves will not do this, indicating that this trait arose through domestication. Dogs and humans have developed a strong human-animal relationship that transcends clade.

…what about chickens, though? It can be daunting, searching for a research question that has yet to be asked, but I gotta hand it to myself. No one has asked this question of chickens before.

For my thesis, I plan to run a collection of tests to determine whether chickens and humans can form such a relationship. The first of these tests, which I will go into below, is the open field test.

Open field tests are pretty self-explanatory: an animal is introduced to a wide, unfamiliar arena, and we record their behavior. Most species behave similarly, initially showing some fear or hesitation, followed by exploration of the new space. The intensity of the behaviors displayed, as well as amount of time it takes to transition between them, are some of the usual measurements. In the case of chickens, their classic behavior in an open field is “freezing”: standing completely still, head stretched high as they look around for possible threats. They may also vocalize loudly, calling to locate conspecifics, aka other members of their species. Eventually, the chicken will unfreeze, stepping further into the field and dipping their head to peck at the floor. Their vocalizations may change as well as they grow accustomed to their isolation.

Chicken behavior in an open field is the result of two contradictory desires: the desire to remain undetected by predators and the desire to find their flockmates. This idea was put forward by Susan Suarez and Gordan Gallup, who conducted a series of tests in the 1980s on open field behavior in chickens [these papers are not open access, however this paper describes the studies well]. Suarez and Gallup argued that chickens perceive humans as predatory, and provided support for this theory in a 1982 publication on open field behavior in chicks. In the study, the visible presence of a human increased “ambulation latency”, the duration of time before the chicks unfroze and began to walk around the field, which appeared to demonstrate that chickens see humans as predators.

But there are some caveats to consider here. The chicks used in the experiment were 4.5 weeks old, described to have experienced “minimal human exposure during rearing”. So, what this study really demonstrated is that chicks, unfamiliar with human presence, will see humans as predators…a conclusion which can probably be safely applied to most lab animals. However, this definitely doesn’t describe the experience of a backyard chicken. I would like to see this study replicated with adult chickens that have experienced regular human exposure.

Familiarization reduces fear. All animals will show a decreased response to a stimulus over repeated exposures – this is known as habituation. After a period of regular interaction with one human, chickens will learn that the person is not a threat, and they’ll stop responding in fear. So, once chickens are familiarized with a human, how will that human’s presence affect their behavior in an open field? Is it possible that human presence could buffer their distress?

In a previous post, I described how my hens would run to me whenever they caught sight of me. This is not behavior they would exhibit towards a predator…in fact, my anthropomorphic mind immediately thinks that it’s because they like me. Now, did my hens approach me simply because they associated me with food, and that motivation surpassed any possible “predatory overtones”? Or had we developed some kind of human-animal relationship? I couldn’t know for sure with my hens, but in my thesis project, I’m making sure to remove the food connection altogether. And Suarez and Gallup’s conflicting motivations in an open field make me dream big: if the familiarized chickens run over to me during the open field test, what would be motivating them? Am I protection from predators? Or perhaps they view me as a social companion, and this fulfills their desire to reunite with their flock? Regardless of the reason, it would be far beyond my expectations if I observed a behavior like that!

To recap, I’m using the open field test, along with other measures of behavior, to assess interspecific (“between-species”) social interaction between chickens and humans. I’ll compare open field behavior when there is a familiar human present to when there is not. If such a human-animal relationship exists, then I would expect the chickens to show a reduced fear response when I am present in the open field. I’m going to test both a domestic breed of chicken and the red junglefowl, the wild ancestor of chickens. Again, if such a human-animal relationship exists, then it would have arisen through domestication, and therefore I shouldn’t observe a reduced fear response in the junglefowl.

Of course, I have no idea what I’ll actually observe. It’s possible the junglefowl will be sensitized to my presence, increasing their fear response when I am in the open field with them. Or maybe, neither the chickens nor the junglefowl will be affected by my presence at all. It’s even possible that each individual bird will act completely differently! That’s the fun of science, though, and I can’t know until I try 🙂