Ethology – Definition and Uses
In this post, we wanted to present another very interesting subject: ethology. First, a definition. Ethology consists of studying animal behavior. What is implied by “behavior”? We can mention here animal communication, predation, mating, migration. Moreover, these different behavioral traits are most often studied in the animals’ natural environment.
In ethology, a distinction is often made between two aspects of the study of behavior, the first being all that constitutes instinct (i.e., the behavior that animals inherit and exhibit for no reason) versus learning (behaviors that animals develop over the course of their lives) [1]. Fields related to ethology include neuroethology, behavioral ecology, sociobiology, wildlife biology, evolutionary psychology, comparative psychology, neuroanatomy, neurobiology and zoology.
Ethology can be useful for different reasons. One can mention animal conservation. Indeed, the conservation and protection of species is facilitated by a better understanding of its behaviour in its natural habitat. Other applications will be presented in the “application” section. But first, a little bit of history.
A Brief History of Ethology
Before we get into what ethology is today and what applications the field has, let us journey back to when ethology as we know it was first invented. Almost a century ago, in the 1930s, Austrian biologist Konrad Lorenz started his work on the behavior of animals [2]. A lot of his research and studies were done in close cooperation with Dutch zoologist Nikolaas Tinbergen and German insectologist Karl von Frisch. In part with their help, Lorenz established ethology as we know it today. At this time, the general perception was that all key behaviors of animals were taught. In contrast, Lorenz believed that the behavior was a product of genetics. An example he gave was that birds, without having any training still were able to fly. Lorenz also coined the term “bullying” which he observed when social animals would cast out individuals whose behavior deviated from the norm.
Photo from the Nobel Foundation archive.
Photo from the Nobel Foundation archive.
Photo from the Nobel Foundation archive.
A common example of ethology that is taught in biology classes today is the behavior of gull (also called seagull) nestlings when they are hungry. The parent gulls have yellow beaks with a red spot (see image below), and when the gull nestlings are hungry they will peck on that red spot because the parent will respond by regurgitating food to them [3]. The discovery and classification of this behavior was one of Nikolaas Tinbergen’s works. This pecking behavior coined the term supernormal stimulus, which is defined as a stimulus that elicits a certain response more strongly than the stimulus for which it evolved. This might be a little hard to grasp, but take the example with the gulls. The hatchlings’ pecking originates from wanting food, but when Tinbergen put a yellow pencil with three red bands in the nest at the same time as the parent arrived with food, the hatchlings would peck at the pencil and completely ignore the parent. So, the exaggerated stimuli from the pencil yielded a stronger signal to the hatchling than its parents’ beak.
Karl von Frisch’s contribution to the growing field of ethology was mainly through his elaborate studies on bees [4]. Von Frisch studied both the behavior and communication of bees, and he discovered that a bee who finds nectar would communicate this to the rest of the hive with a dance that specifies the direction, size, and quality of the source. Now that is one informative dance !
Tinbergen, Lorenz, and von Frisch together received the Nobel Prize in Physiology or Medicine in 1973 “for their discoveries concerning organization and elicitation of individual and social behaviour patterns” [5].
Ethology Today
Although very interesting, let us move on from the history of ethology to what it is today. Ethology today has blossomed into a whole plethora of different research topics, and they often integrate other fields of biology such as genetics, neurology, epigenetics and ecology to gain a deeper understanding of how animal behavior is affected by different factors. Let us take you through some examples of interesting ethology research that is going on today.
Five years ago, the global livestock population was 22.8 billion chickens, 1.5 billion cattle, 1.2 billion sheep, 1.2 billion ducks, 1 billion goats and 967 million pigs [6]. These numbers are probably even higher now, since a bigger human population increases the demand for food production. With such an insanely large livestock population, it is of high interest to farmers that they maintain a good living environment and welfare for the animals.
A research group, the Jensen Group of Linköping University in Sweden, aims to study the behavior of domesticated animals [7]. The group has two aims, to study how behavior is affected by domestication, and how we can use behavior to assess the welfare of human-kept animals. They explore e.g. the epigenetics of behavior, and write that “…an animal that experiences stress will obtain epigenetic modifications to its genome, which in turn will affect how it responds in other situations.” They also say that these epigenetic modifications can then even be transferred to future generations! This type of research could also help increase the welfare of other non-domesticated but human-kept animals, like the ones in animal parks.
In many cases of ethology studies, the methodology is to subject an animal or a group of animals to certain stimuli in the lab and note any responses in behavior that take place. The problem with in-lab ethology experiments however, is that one can never truly replicate 100% of all the stimuli and environmental factors that would be present in the animal’s natural habitat. Even when researching animal behaviors in the wild, human disturbance is a factor that must be considered as a scientific bias. An interesting way of tackling this problem and reducing the scientific bias, is the use of robots to do the surveillance instead. A study found that when approaching wild penguins with a remote-operated vehicle, they had significantly lower stress responses compared to when approached by humans [8].
disturbance in research
on wild animals” by maho et. al.
A step further is to not only have robots perform surveillance, but to also have them look like the animal of interest and mimic their behaviors. This opens up the possibility to record animals’ responses to specific behaviors. A fascinating research project that has tried to tackle this is that of Frank Bonnet et. al. [9]. In their article, they propose a modular robotic system that mimics small fish locomotion and body movements to use for ethological studies. In another article, they continue on the subject matter and discuss “How mimetic should a robotic fish be to socially integrate into zebrafish groups?” [10]. This type of research really opens up a whole new avenue of ethology, and I think it is on the right path for advancing ethology in the future.
And now, what does the future hold for this field ?
According to an analysis in an article, there is still a lot of work to be done to improve the study of this field [11]. Indeed, the first point to emerge is that there is no real consensus among researchers on the basic concepts of ethology, even in the name of the discipline. Secondly, the studies carried out are very much focused on primates. It would be interesting to extend and diversify the species studied. Finally, the tools available can be a source of bias and prevent relevant conclusions from being drawn.
As mentioned several times in the article, ethology will be a real support, because of the variety of fields involved, for animal conservation due to climate change. Indeed, global warming and its induced changes will be a real challenge for animal adaptation. A better knowledge of species will allow us to better understand their future.
Another point to improve in the future that can be mentioned is the lack of dialogue and collaboration. For example, there is a real need to improve the tools and their technological aspects, by integrating more engineers in the field. Like we mentioned in the “today part”, involving robots and tech innovations can be really helpful.
Sources
[1] https://www.masterclass.com/articles/guide-to-ethology-exploring-the-study-of-animal-behavior
[2] https://www.britannica.com/biography/Konrad-Lorenz
[3] https://www.sciencedirect.com/science/article/abs/pii/S0003347209000165
[4] https://www.nature.com/articles/nature03526
[5] https://www.nobelprize.org/prizes/medicine/1973/summary/
[6] https://storymaps.arcgis.com/stories/58ae71f58fd7418294f34c4f841895d8
[7] https://liu.se/en/research/jensengroup
[8] https://www.nature.com/articles/nmeth.3173′
[9] https://journals.sagepub.com/doi/full/10.1177/1729881417706628#body-ref-bibr1-1729881417706628
[10] https://www.researchgate.net/publication/320067775_How_mimetic_should_a_robotic_fish_be_to_socially_integrate_into_zebrafish_groups
[11] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8472011/
Hi ! My name is Rosalie.
I’m in my second year of Biology. I love swimming, dancing but also mountains and aircrafts. In biology I like plants and microbiology