In this article, I would like to take a closer look at the topic of domestication, which Corinna already touched on in a previous article.
Most of you have probably heard of the term domestication before, but what it exactly means is often unclear.
Domestication describes the process of change or evolution within a wild species (referring to an animal or a plant). During this process, in terms of reproduction, certain individuals are being isolated from their wild counterparts. Therefore, through natural and artificial selection, an optimal genetic adaptation to the human environment occurs over time (Clutton-Brock, 1995). So, what does this tell us?
In plain English, it means that domestication (in animals) is a prolonged process of becoming a pet that takes place over many generations and actually leads to permanent genetic change in the species. So, it is not a matter of socialising or taming a particular individual. In other words, I cannot domesticate a wolf/turn him into a pet by raising him with a bottle and desensitizing him to humans. Of course, such a wolf will behave differently to a wild animal. However, through socialising with humans from early on, I only modify the behaviour of this animal, but not its genes (admittedly, it’s not all about the genes and the environment, but also the relationship between the two, the so-called epigenetics... but let’s not go there for now).
So, are all dogs really descended from wolves?
Charles Darwin already asked that question in 1868. He was not the only one to notice that different dog breeds are very heterogeneous (different) in their appearance. Think of the Great Dane and the Chihuahua, for example. It’s hard to believe that they have the same ancestor, but nowadays this fact is based on genetic and behavioural evidence (Zimen, 1971; Coppinger & Smith, 1983). So other animals like the jackal, the fox and Co. played no role in the evolution of the dog, but only the wolf.
But when did domestication begin?
This is not so easy to answer, and scientists still haven’t completely agreed on when and where the birth of the dog took place. The reason being is that the genetic methods of science have improved over the years (and continue to improve). So, there are always new discoveries or even new archaeological findings that provide clues to the beginnings of domestication. For example, the skull of the so-called Altai dog was found in Central Asia, estimated to be 32 - 36,000 years old. With the help of genetic studies, it was shown that it is indeed a dog skull and not a wolf skull (Druzhkova et al. 2013). Other research groups (e.g., Thalmann et al. 2013; Frantz et al. 2016) also assume that the origins of domestication go back at least 32,000 years and that the dog is, therefore, the first domesticated species ever. In fact, the domestication of the dog took place before humans became sedentary (Larson et al. 2012). You see, it was a while ago. A fairly recent study by Frantz et al. (2016) tried to combine genetic and archaeological methods and found evidence that East and West Eurasian dogs evolved independently from two different wolf populations. I find this very exciting, as it fits wonderfully with the different theories of many other discoveries (Whyte, 1950).
What I mean here is that certain discoveries were often found at the same time by different people in different places, for example, the theory on the evolution of species by Darwin and Wallace. Perhaps time was simply right for the alliance of wolf (dog) and man?
Since Corinna has already described in detail in her article why wolves and humans of all species might have decided at some point to live together (keyword social similarity), I will skip this part and instead dive into the question of :
Who made the first move and how?
In fact, there are various scientific theories regarding the beginnings of domestication, but they do not have to be mutually exclusive.
As a first step, it is assumed that a group of less fearful wolves followed the nomadic humans and used their leftovers as a food source (Coppinger & Coppinger, 2001). People tolerated the proximity of the wolves because it brought along certain advantages for them. For example, wolves announced by barking to the humans that strangers or animals were approaching (the wolf's bark is more of a deep woof and serves as a warning sound).
Besides this theory of population-based selection, there are also other theories. The so-called individual-based selection assumes that humans found wolf babies and raised them. Amongst these wolves cubs, those less shy and aggressive towards humans were probably at an advantage. They survived and were able to pass on their genes accordingly (e.g., Lorenz, 1950; Paxton, 2000), while fearful biters were killed.
Presumably, these two theories intertwine. After all, our ancestors were more likely to stumble upon a group of abandoned wolf cups if their parents had previously become closer to humans and nibbled on their scraps. Over time, this rather unconscious selection became more and more an artificial one, meaning humans at some point began to specifically mate certain dogs with each other (Müller, 2002).
Paxton (2000) also suggests the idea of co-evolution between dogs and humans.
This concept is very interesting, as it assumes that through the alliance with wolves, not only the wolves but also humans have changed. This human-wolf (dog) complexity was probably more successful than just the evolution of one species alone. Even the possibility that the Neanderthal man was eradicated thanks to the human-dog alliance is something that is being discussed. A daring thesis, but one that gives us dog owners a certain satisfaction (at least it does to me).
we can say that the topic of domestication is still based on a lot of theories and assumptions, at least until now, and the last word has definitely not been spoken (I am waiting for the next ground-breaking genetic study). Nevertheless, I think it is very informative to take a closer look at the beginnings of dog evolution, as it not only tells us something about our four-legged friends, but also a lot about ourselves.