ClassX Video Lessons Youtube Channel Curiosity Stream The Science Behind Irresistible Puppy Eyes | The Science of Cute
Have you ever noticed how some dogs can give you those adorable “puppy eyes”? This cute expression is something wolves can’t do, and it’s all thanks to a special muscle around their eyes. A recent study published in the Proceedings of the National Academy of Sciences found that dogs have different eye muscles compared to wolves. Specifically, dogs have more developed LAOM and RAOL muscles, which help them raise their eyebrows and communicate with us in a unique way.
Understanding how dogs can make these expressions is interesting, but why do they do it? The answer might be linked to how dogs were domesticated. Interestingly, huskies, a breed closely related to wolves, can’t raise their eyebrows like other dogs. This is because huskies don’t have the same eyebrow muscles. Huskies were bred for tasks like pulling sleds, not for companionship, which might explain why they didn’t develop this trait.
Long ago, wolves started following humans, hunting the same animals. This relationship, known as commensalism, was beneficial for both species. As humans settled and built permanent homes, wolves began to interact more with them. This interaction eventually led to the domestication of dogs, although the exact details of when and how this happened are still debated.
In the late 20th century, a Russian geneticist conducted an experiment with silver foxes, breeding them for tameness. Over just ten generations, not only did the foxes become friendlier, but they also developed physical changes like floppy ears and varied coat colors. This experiment showed that selecting for tameness can lead to these cute features, a phenomenon known as domestication syndrome.
Domestication syndrome explains how traits like floppy ears, smaller teeth, and different coat colors appear in domesticated animals. This is linked to neural crest cells, which are special stem cells in developing embryos. These cells form various parts of the body, including muscles, cartilage, and skin pigment. Changes in these cells during development can lead to the cute features we see in domesticated animals.
So, the next time you see a dog giving you those irresistible puppy eyes, remember that it’s a result of thousands of years of evolution and domestication, making them not just our companions but also masters of cuteness!
Draw a diagram of a dog’s face and label the LAOM and RAOL muscles. Use different colors to highlight these muscles and explain how they contribute to the “puppy eyes” expression. Share your diagram with the class and discuss how these muscles differ from those in wolves.
In groups, act out the journey of domestication from wolves to modern dogs. Assign roles such as early humans, wolves, and domesticated dogs. Focus on how interactions between humans and wolves might have led to domestication. Present your role-play to the class and discuss the key moments in this evolutionary journey.
Research the physical and behavioral differences between huskies and other dog breeds that can raise their eyebrows. Create a Venn diagram to compare and contrast these differences. Present your findings to the class, highlighting why huskies might not have developed the same eyebrow muscles.
Work in pairs to experiment with your own facial expressions. Try to mimic the “puppy eyes” look and observe which muscles you use. Discuss how these expressions might help in communication, both in humans and dogs. Share your observations with the class and relate them to the concept of domestication syndrome.
Conduct a mini-research project on domestication syndrome. Find examples of other domesticated animals that exhibit traits like floppy ears or varied coat colors. Create a poster showcasing these examples and explain how neural crest cells contribute to these traits. Present your poster to the class and discuss the science behind domestication syndrome.
Sure! Here’s a sanitized version of the transcript:
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Meet Lucy. Right now, she’s doing something that wolves can’t do: raising her eyebrows. We’ve all seen dogs do it; it even has a name: puppy eyes. But how dogs can do this was only recently revealed in a paper published in the Proceedings of the National Academy of Sciences. The paper demonstrates that the musculature surrounding the eye differs in dogs compared to wolves. In particular, the LAOM muscle is associated with the eyebrows, and the RAOL muscles on the sides are more present in dogs than in wolves, suggesting that dogs might be using their eyebrows expressively to communicate with us.
However, knowing how a dog can do this doesn’t answer the question of why they do it. The answer may lie in how they were domesticated in the first place. A hint can be found in the fact that there is one breed of domesticated dog that also can’t raise its eyebrows: the husky. Huskies are genetically closer to wolves than any other breed of dog, and like wolves, they lack the eyebrow muscles that other dogs possess. One of the authors of the scientific paper that described this difference is Professor Rui Diogo, who has a husky named Wolfie.
Wolfie is a husky, and he represents one of the more ancestral lines, genetically and morphologically. When we dissected huskies, we found that they don’t have the same muscles as other dogs. For example, chihuahuas, which are also quite ancestral, do have these muscles. Huskies simply cannot do the puppy eyes. If I make a gesture, he wants it, but he won’t give those puppy eyes like other dogs do. That is a significant difference.
It’s now thought that huskies didn’t develop puppy eyes because they never needed them. They were selected for tasks like pulling sleds in the Arctic, not for companionship. Huskies can be cute, but they don’t interact as much with humans and are generally more detached than other dogs that were bred for companionship.
Companionship was certainly not on the minds of wolves when they first began to pay attention to humans. It’s believed that even before the first agricultural revolution, at the end of the last ice age, wolves began to follow our nomadic ancestors, hunting the same animals. This relationship is known as commensalism, where both species benefit from the same resources. However, when our ancestors settled and built permanent encampments, a significant change in our relationship with wolves began.
The exact timing and nature of domestication remain controversial. We don’t know when, where, or how it happened. It may have been that an ancestral dog-wolf gained evolutionary benefits from interacting with humans, particularly in terms of access to resources. As humans became sedentary, they generated waste, providing food resources that dogs could scavenge. This interaction may have been mutually beneficial, with humans gaining protection from predators.
A key insight into how dogs became cute and cuddly came in the late 20th century when a Russian geneticist decided to breed silver foxes based solely on their tameness and lack of aggression. The results were dramatic and unexpected. Since the 1950s, researchers have been selecting for traits related to tameness and interaction with humans. In roughly ten generations, not only did behavioral changes arise, but physical features also changed.
The experiment with silver foxes showed that we were selecting for tameness, and some of the cuteness is a byproduct of this selection. For instance, the ears of tame animals tend to be floppy, and their fur may display a mix of colors. The snouts and teeth also become smaller, leading to a more juvenile appearance. These changes are not directly selected for; rather, they are byproducts of selecting for tameness, a phenomenon known as domestication syndrome.
But how could this domestication syndrome connect such a diverse range of characteristics like floppy ears, small teeth, varying coat colors, and changes in aggression? The answer lies in the early stages of development in the pup embryo, specifically relating to a group of multipotent stem cells called neural crest cells. These cells migrate throughout the developing embryo to form muscle, cartilage, and skin pigment cells, as well as the adrenal glands.
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This version maintains the core information while removing any informal language or unnecessary details.
Dogs – Domesticated mammals that are often kept as pets and are known for their loyalty and companionship. – Dogs have been bred for various purposes, including hunting and herding, due to their diverse traits.
Wolves – Wild carnivorous mammals that are ancestors of domestic dogs and live in packs. – Wolves play a crucial role in their ecosystems by controlling the population of other animals.
Muscles – Tissues in the body that have the ability to contract and produce movement or maintain the position of parts of the body. – The muscles in a cheetah’s legs allow it to run at incredible speeds.
Domestication – The process by which humans breed plants and animals for particular traits, making them more useful to humans. – The domestication of plants and animals was a key factor in the development of human civilizations.
Tameness – The quality of an animal being gentle and not afraid of humans, often as a result of domestication. – Tameness in animals like rabbits makes them easier to handle and care for as pets.
Traits – Characteristics or features of an organism that can be inherited or influenced by the environment. – Traits such as fur color and ear shape can vary widely among different breeds of dogs.
Evolution – The process by which different kinds of living organisms develop and diversify from earlier forms during the history of the earth. – Evolution explains how species adapt to their environments over time through natural selection.
Animals – Living organisms that feed on organic matter, typically having specialized sense organs and nervous systems and able to respond rapidly to stimuli. – Animals like birds and insects play important roles in pollinating plants.
Cells – The basic structural, functional, and biological units of all living organisms, often called the “building blocks of life.” – Cells in plants have a rigid cell wall that provides structure and support.
Features – Distinctive attributes or aspects of an organism that help in identifying or classifying it. – The features of a bird, such as its beak shape and feather color, can help scientists determine its species.
