Julia Zichello
Appearances
Freakonomics Radio
624. The Animal No One Loves, Until They Do
Not to say anything negative about the hamsters of the world, but I think it's a different relationship.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
The first rats that were domesticated, they were pets in Victorian England, and they were not thought of as negatively as we think about even pet rats today. So it was revered to have a rat on your shoulder.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
During the pandemic, I got a car for the first time because alternate side of the street parking was relaxed. I kept it in one place for too long. I also don't really drive that often. So yes, when I went to start it, it didn't start. And I had to get it towed. And the mechanic told me that there was bedding in there connected with rats and also orange peels. This was in the engine?
Freakonomics Radio
624. The Animal No One Loves, Until They Do
This was in the engine. It was the late fall, early winter, which is just the time that they would be looking for a warm place. I thought it was really funny at first before I got the bill from the mechanic. What did it look like inside the engine? The wires were gnawed.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
You can see shards or pieces of the wire and then the orange peels and some dry leaves and other things that they were using for nesting material.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
I don't know, but it may have been, which is, you know, kind of cute.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
Yeah. So I inherited rats from a family member who moved to a building that could no longer have pets. The rats were already, I believe, 18 months old. I felt the same way most people would feel, the like, oh, no way kind of thing. Like, oh, my gosh, their tails. Everyone's so upset about their tails because they're so gross. But, you know, then I warmed to them over time.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
Eventually, because you're feeding it, because it's a little bit lovely, then you end up feeling some warmth towards it. What kind of rats were your pet rats? They were two different breeds. One was agouti, and that was sort of silver-colored. The other was a hooded rat, which was white with just a little bit of black on their head and striped down their back.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
One was named Sylvie and the other was Pele. They were both males.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
Correct. No offspring. You know, they were fun to watch. They were interactive. They eat a lot of different things. We had some fun feeding them the circular corn chips. They would take the corn chip like you would a steering wheel of a car and turn it around and eat it around the edges. One thing I noticed about the two pet rats is that they had different personalities from one another.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
Sylvie was much more bold and Pele was much more cryptic. They ate food in different ways. Peli would take the food and go into this little hidey box and Sylvie would just unabashedly eat the food out there in front of you. Do they vocalize? They did. Not a lot. Technically, rats do vocalize.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
Only when we were socializing with each other. They were not super vocal that I heard. And I think there are sounds we can't hear.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
I don't know about that. Is it like a squeaking kind of thing? Yes, very, very light squeaking. Not like long vocalizations. They were not singing. There's been some research showing that rats can laugh when they're tickled. Those are things that you can't hear with the human ear, though there were special recordings that were showing that.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
They also were very responsive to all of the sounds in the environment in the apartment. Things like the coffee grinder. I was noticing that the hooded rat was really stressed out when I was grinding coffee.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
I mean, I couldn't do anything. I had no room to move them and I couldn't stop drinking coffee.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
No, no. I just noted it and continued on with the grinding. You know, their sensory systems are so acute. Obviously, their olfaction, their sense of smell is really good. Their hearing is really good. And they seem very sensitive to things in their environment. It did also make me think about the rats in New York City.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
There aren't a lot of studies about the behavior of wild rats from the perspective of the rats. One of the things I thought about after having the pet rats is that I wonder if the rats in New York City are very, very stressed. They like to be underground. When you see them skittering across the sidewalk, it stresses you out, but I'm pretty sure that they're also highly stressed.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
I don't know about the widespread embrace of pet rats, but I think the rat czar in New York, I think that she should have a pet rat. If you want to control them or if you want to love them, you have to know about them.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
So they both passed away, sadly. One of the things that happened towards the end of their life, which also is something that's relevant to all rats, is that they aged so quickly. And they started to show signs of aging, like being hunched over, losing body fat. One month in a rat's life is equal to three years in human years.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
People know this because there's a lot of people, obviously, who use rats in the lab trying to study aging and trying to make that equivalent. So they aged very rapidly. We don't really exactly know why they died. They didn't show any signs of disease that we could see. But one of the things that happened that was very sad is that Sylvie died first. And then for Pele, he was alone.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
So we bought him a little toy that was the shape of a rat because I knew that he would be lonely. It was a cat toy. He was not interested in the cat toy. And then he died less than a week later. This is typical of rats because they're so social. They really like to have other rats around.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
I think maybe, yeah. We knew that the lifespan of domestic rats is around two years and they were two and a half years old. So, you know, they lived a good life. We certainly appreciated them and learned a lot.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
I will never see a squashed rat in New York City again and not think about our pet rats. I know that they are different. The rats in the wild are more aggressive. It wouldn't be the same thing as the pet rats that I experienced. But I mean, of course, you'd think about your pet.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
Definitely not. I'm definitely not getting pet rats again.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
It's too heartbreaking. Their lifespan is too short. And the relationship between their charm and their lifespan is too asymmetrical.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
There are many studies across neuroscience and pharmaceuticals and psychology that used rats for decades. The rats that are lab rats are more genetically homogenous than wild rats. Rats and humans shared a common ancestor 90 million years ago. That's not super close, but it's close enough to have revealed things about the brain and behavior and genetics that have ultimately helped humans.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
So I wonder about how many people have technically been helped by that versus the number of people who have been harmed by diseases they may have acquired from a rat.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
The common ancestor was an animal that lived in the late Cretaceous around the time of the dinosaurs. There's not a specific name, but we use genetics to understand how far back these common ancestors lived. The anatomy and behavior of that common ancestor was much more rat-like than it is human-like. They were likely nocturnal. Some of them may have been insectivores.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
And their basic anatomy was much more rat-like than humans.
Freakonomics Radio
624. The Animal No One Loves, Until They Do
Yeah, so that makes rats good model organisms because you can have many offspring within your human life as a scientist studying them. So you can see how things translate from one generation to the next. One rat female can have up to 72 pups per year. Wow. Wow.