(speaker) This rat is driving a tiny car designed specifically for animals.

It can go whichever direction it wants, but it's trying to find a tasty treat.

(speaker 2) It is shocking how much you can train these animals to do.

It's challenging to think about the thoughts of a rat.

And because they cannot express themselves verbally, we need to try to understand what a rat is capable of doing.

We need to channel our inner rat.

[cheerful music playing] Welcome to Animal IQ.

In each episode, we rank the intelligence of animals using our handy rubric and the five intelligence domains.

(speaker 2) Each domain is affected by genetics and evolution and environment, among other factors.

And even though directly comparing intelligence is something that experts don't do, this rubric does give us a way to illustrate where science thinks an animal might fall as of now.

And our rubric is based on scientific research, expert interviews, and a bit of our own expert opinions.

(Trace) The animals we've been talking about over the last several episodes, they tend to be pretty social.

They tend to have pretty good memories, which means they're filling up our rubric quite well.

But we haven't yet talked about one of the dark horses of scientific animals, and that is the rat.

Rats have an encephalization quotient or a brain-to-body-mass ratio of 0.8.

It doesn't actually mean how smart they are.

Humans, we are a 7.5 on the EQ scale.

(Kelly) The rat brain is very small compared to ours, two grams, compared to the 1400-gram brain that humans have.

But it generally has all the same parts, a cerebellum, and a hippocampus, and a cortex.

And the cells, the neurons look exactly the same as our neurons.

And those shared evolutionary roots have made them a popular model for over 150 years in scientific studies.

They have complex cognitive and emotional capacities, which is why experts can create cleverly-designed experiments like the rat car.

I'm all about natural behaviors, usually.

So at first, I thought, "Why would I want to do that?

That's very artificial."

But it's an acquired behavior, and it certainly taps into some sophisticated learnings.

So we got the model going in this novel environment to grab the bar that would drive and then steer to the Froot Loop tree.

[chuckles] That's our treat tree.

You had to look to see where your goal was and then maneuver accordingly.

It became a very sophisticated learning task or cognitive ability that takes weeks and even months to teach the animals to do.

And very often, when we're studying learning in rats, we do something very kind of quick and dirty, something we could train them to do in two to three days.

So it gave us a new learning task where we could look at long-term learning and to see how that training changes the brain.

The animals in the enriched environment could learn to drive much faster than the ones in the standard environment.

So that was a good lesson for all of us, to see that-- our context, how engaging our world is may influence how readily we can learn new tasks.

So with rats we know a lot, but there's still a lot to learn.

(Trace) We know that rats have a great capacity to learn new things.

They can map their environment, they have a good memory.

But are rats aware enough to know that they're getting their intelligence tested?

(Kelly) What you're suggesting, Trace, is a fancy, sophisticated ability known as metacognition, that we're aware of our own cognition and cognitive abilities.

There's some research that suggests they're aware of what they do know and don't know, and they act accordingly.

Whether or not they know it's a test, they see new opportunities.

By "opportunity," she means opportunity for reward, like food or water.

And the rat wants that reward.

In one study, researchers gave rats the choice-- to take the test and get a big reward if they succeeded, or decline the test and get a smaller treat.

When they could make this choice and they thought they'd fail, they took the smaller treat.

It's like they knew what they didn't know.

If the rats weren't given the option to decline the test, they would perform badly.

It was like they were forced to do it and they didn't want to do it in the first place, like a pouty kid.

The rats know what they don't know, and they know that they don't want to be pushed, which is a big indicator of smarts.

Right, so when researchers create an environment where rats can learn on their own, they will, because they choose to learn.

They are thinking about their learning.

(Kelly) I think rats' both internal and external awareness is pretty impressive, and this is related to their survival.

They're almost like little spies.

"Something's up.

I need to make sure this is a safe environment before I proceed."

So they don't really have that reputation when people think of them just going through the garbage and such, but they are very vigilant about their external world and noticing if anything is different and then determining if it's safe.

So I think we have some things to learn from them when it comes to being mindful of our internal and external surroundings.

That's not all, though, just like humans, rats are extremely social.

(Kelly) They are healthier and seem to prefer having roommates instead of being individually housed.

And when you separate them, their stress hormones will go up.

When animals are grooming, other animals are engaging in parenting behaviors or responses.

This oxytocin increases, and that reduces stress hormones.

We can also experimentally test things like social bonding, empathy, and pro-social behaviors like helping others in need or cooperating with each other.

And rats do show these behaviors.

They'll help other rats even if it means delaying or foregoing a reward.

And to build on that, in a study where rats were allowed to provide grooming or food to a partner, they would remember if their partner was nice to them in the past, and then they would offer grooming or food for the future.

This reciprocity, or tit for tat returning of a favor, it shows that rats aren't just grooming to be nice.

They get that abstraction of the old concept, "If I scratch your back, you'll scratch mine," even if that means giving food.

(Natalia) I don't think there's any domain, except maybe awareness, where rats don't squeak out a good lead over some of the other animals.

(Trace) For the X-factor, I think that we should go right down the middle.

We know a lot about lab rats and their capacity for learning, but we have a lot to learn about wild rat cousins as our expert, Kelly, said.

We're interested in comparing wild rats and their brains and how complex they are to the laboratory rats.

That'll give us a gauge about how valuable the laboratory rat research really is.

We need to know this because we're doing this research to learn more about ourselves in some cases, about our mental health.

So we need to have a mentally healthy rat if we're going to study mental health or mental illness and not just assume that you could stick an animal in any environment, and it's going to give you valuable results.

So understanding how more authentic natural environments influence the brain, I think will give us clearer ideas about how to translate that information to humans.

Absolutely, something that lab rats get that wild ones don't, they love being tickled.

They don't naturally get to go in the wild, but if a human tickles them, they'll seek it out from other humans.

They even record ultrasonic vocalizations while they're being tickled that might be rat laughter.

(Trace) Thanks for watching, everyone.

Tell your friends how surprisingly great rats are.

And if you were thinking about getting one as a pet, share this video with your mom as proof.

Hi, mom!

If you have ideas for future animals, make sure you drop us a line, and we'll see you next time on Animal IQ.

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