From the brains behind Brains On, this is the moment of um.
Answering those questions that make you go, um...
Moment of Um comes to you from APM Studios.
I'm Anna Wegel.
I'm at the dog park with my pup Cece.
We've already done a few laps to say hi and sniff butts.
I mean, Cece does the butt sniffing.
I'm more of a hug and chat kind of gal.
Anyway, the dog park is hopping today.
There's Pretzel the Golden Retriever chasing Leroy the Dachshund.
Peanut the Chihuahua is ferociously guarding her tennis ball.
Oh, oh, and Marlene the pug and Toby the St.
Bernard just arrived.
Wow, so many good dogs in so many sizes, from itty-bitty to, well, St.
Bernard size, which is big.
Hmm, I wonder why dog sizes can be so different.
I mean, cats come in different colors, but they're mostly the same size.
So what makes dogs different?
Theo and Wilfred were curious too.
Why are some dogs so small and others so big?
Good thing I know exactly the right person to fetch the answer.
Haha.
The reason dogs come in so many sizes is because, over thousands of years, we've given them a ton of different jobs to do.
My name is Anna Goldfield and I'm a producer at Brains On, but I'm also an archaeologist and I love talking about things that people did in the past.
I also love dogs.
We're not exactly sure when the first wolves began hanging out with humans, but researchers think it was at least 23000 years ago and probably even earlier than that.
These early humans were hunter-gatherers, and so they realized that having these wolves around could be pretty helpful for tracking and hunting prey and for extra protection from other big predators.
The first wolves to be brave enough to stay around humans would have had puppies, and those puppies would have been raised around people.
And so gradually, over many generations of puppies, and because humans took special care of the pups that were the least aggressive towards people, the best at sniffing out prey and things like that, we start to see enough differences in these canines' DNA that they're different from humans.
When you choose which animals get to have babies, which is what these people were doing with the wolf pups you're basically saying I want these characteristics in the next generation.
And so what's actually happening is that you're selecting animals with specific genetic traits.
Behavior and appearance are both part of the genetic code that makes any living thing the way it is.
So if you make those selections over and over and over again, you're actually slowly changing the animal's genes.
So with dogs we see changes in behavior, like being much less aggressive, being good at understanding how humans communicate with words and body language, stuff like that.
But we also see physical things that sort of genetically came along for the ride, like floppier ears and more rounded faces instead of the super pointy ears and long snouts that wolves have.
When people wanted dogs to help them with jobs, they would use the exact same process, except the things they were looking for in puppies would be specific to those jobs.
So a dog, whose job, let's say, was to guard farm animals, would be pretty big and be really good at paying attention to what the animals were doing and what was happening around the farm.
If you wanted a dog just for cuddling and companionship, you'd probably want them to be small and really friendly.
So all of these jobs hunting tracking guarding herding, running really fast, being little lap dogs all these different dog breeds and their different sizes are the result of people choosing what jobs they wanted dogs to have over many many many many, many years.
That is so cool.
More than 20,000 years ago, wolves started hanging out around humans hoping to score some free food.
The dogs we know and love today are descended from those wolves.
Dogs have helped humans do lots of different jobs throughout history, and that's why they come in so many different sizes.
Over a long time and lots and lots of doggy generations, dogs started to look different from each other based on the job that humans wanted them to do.
Take St.
Bernard's, for example.
They originally had the job of rescuing people lost in the snowy Alpine mountains.
They're big, strong, love people, and have lots and lots of long fur to keep them warm in the cold.
And, oh jeez, it looks like Cece found a giant mud patch to dig around in.
Cece, no!
No, Cece, no!
Oh my goodness, you are so dirty.
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Until then, rough!
Okay, my muddy little buddy.
I guess we gotta get you home for a B-A-T-H.
You don't know how to spell.
