Hi there! Have you ever wondered why some of our favorite pets, like dogs and cats, have smaller brains compared to their wild relatives? Let’s dive into this interesting topic and find out why domesticated animals often have smaller brains.
When animals become domesticated, they go through many changes. This includes animals like dogs, sheep, and horses. One change that might surprise you is that their brains get smaller! For example, the brains of domesticated ducks have shrunk by about 15%, cats by 30%, and pigs by a whopping 35%. Even farmed fish like trout have smaller brains compared to their wild cousins.
Usually, there’s a strong link between the size of an animal’s brain and its body. Smaller animals, like mites, have smaller brains than ants, which have smaller brains than mice, and so on, all the way up to big animals like elephants. This pattern is also true for animals of the same species. For instance, smaller wolves have smaller brains than larger wolves, and the same goes for small and large dogs. However, if you compare a wolf and a dog of the same size, the wolf will have a bigger brain.
In many domesticated animals, the parts of the brain that have shrunk the most are those that handle stress and react to danger—what we can call the brain’s “panic button.” Animals with bigger panic buttons tend to be more alert and ready to fight or flee when they sense danger. On the other hand, animals with smaller panic buttons are usually calmer and more relaxed. These calmer animals were likely the ones humans chose to domesticate because they were easier to manage.
By breeding the calmest animals over many generations, humans have made their panic buttons, and therefore their brains, smaller.
In conclusion, domesticated animals have formed close relationships with humans by undergoing changes in their brains. These changes have made them more suited to living alongside us.
Thanks to 23andMe for sponsoring this exploration into the world of animal brains. With 23andMe’s DNA kits, you can discover your own ancestral history and learn about how your genes affect different parts of your life. Check out their special holiday offer available until December 26th by visiting 23andMe.com/MinuteEarth.
Gather information about different domesticated animals and their wild counterparts. Create a chart comparing their brain sizes. Use this chart to visualize the differences and discuss why these changes might occur. Consider factors like domestication and the role of the “panic button” in your analysis.
Imagine you are a farmer in ancient times trying to domesticate a wild animal. Role-play the process of selecting animals with calmer temperaments. Discuss how these choices might lead to changes in brain size over generations. Reflect on how this activity relates to the concept of the shrinking “panic button.”
Conduct a simple experiment by measuring the body sizes of various animals (or use toy models) and estimating their brain sizes based on the information from the article. Discuss the relationship between body size and brain size, and how domestication might alter this relationship.
Divide into two groups and debate the advantages and disadvantages of having a smaller brain due to domestication. Consider aspects like survival, adaptability, and human interaction. Use evidence from the article to support your arguments.
Write a short story from the perspective of a domesticated animal with a smaller brain. Describe how the animal interacts with humans and its environment. Highlight how its calm nature and smaller “panic button” influence its daily life.
This video was sponsored by 23andMe. Hi, this is Emily from MinuteEarth. Domestication has changed various animals in noticeable ways, including dogs, sheep, and horses, but there’s a less obvious change that many domesticated animals share: reduced brain size. For example, duck brains have shrunk by about 15%, cat brains by 30%, and pig brains by a significant 35%. Smaller brains have even been observed in farmed trout.
This is intriguing because, generally, there is a strong correlation between the size of an animal’s brain and its body size. For instance, smaller animals like mites have smaller brains than ants, which have smaller brains than mice, and so on, up to larger animals like elephants. This relationship also holds true for individuals within the same species. For example, smaller wolves have smaller brains than larger wolves, and small dogs have smaller brains than large dogs. However, when comparing wolves and dogs of the same size, wolves consistently have larger brains.
Moreover, in various domesticated animals, a significant portion of the brain shrinkage has occurred in areas that process external information and regulate responses to stress—essentially the brain’s “panic button.” Research indicates that animals with larger panic buttons tend to have a more sensitive fight-or-flight response, while those with smaller panic buttons are generally more docile. These are the animals we likely chose to domesticate. By selectively breeding the tamest individuals, we further reduced the size of their panic buttons and, consequently, their brains.
In summary, domesticated animals have developed long-term partnerships with humans by undergoing significant changes in their brain structure.
Thanks to 23andMe for sponsoring this video. With 23andMe’s simple DNA kits, you can explore your ancestral history and learn how your genes may influence various aspects of your life, from physical traits to sleep quality. To get your kit and support MinuteEarth, visit 23andMe.com/MinuteEarth. There’s a special holiday offer available now through December 26th; click the link in the description to get kits for you and your family.
Pets – Animals that are kept for companionship and enjoyment, often living in a home with people. – Many people find that having pets like dogs or cats can help reduce feelings of loneliness.
Brains – The organ in the body that controls thoughts, memory, emotions, and actions. – Scientists study how different parts of our brains work together to help us learn and remember things.
Domesticated – Animals that have been tamed and bred by humans for a long time, making them different from their wild ancestors. – Dogs are domesticated animals that have been living with humans for thousands of years.
Animals – Living organisms that can move and respond to their environment, including mammals, birds, reptiles, and more. – In biology class, we learned about the different ways animals adapt to their habitats.
Stress – A feeling of emotional or physical tension that can affect the body and mind. – When students have too much homework, it can cause stress, making it hard to concentrate.
Danger – The possibility of harm or injury, which can trigger a response in living organisms. – Animals have instincts that help them sense danger and protect themselves from predators.
Panic – A sudden, overwhelming feeling of fear that can cause people or animals to react without thinking. – During a fire drill, it’s important not to panic and to follow the teacher’s instructions calmly.
Calm – A state of being peaceful and free from stress or strong emotions. – Taking deep breaths can help you stay calm when you’re feeling nervous before a test.
Relationships – The connections or interactions between people or organisms, which can affect their behavior and emotions. – In ecosystems, relationships between predators and prey are important for maintaining balance.
Genes – Units of heredity that are passed from parents to offspring and determine traits. – Scientists study genes to understand how certain characteristics are inherited in families.
