From the brains behind brains on, this is the moment of um.

Moment of Um comes to you from APM Studios.

I'm Grumps McRank, professional complainer.

There are plenty of things for a professional complainer to complain about.

There's the weather, obviously, which is either too hot or too cold, too dry, or too rainy.

Sometimes it's even too sunny.

The supermarket is also primo complaint real estate.

The bananas are too green or too ripe or too banana shaped.

But when I was taking classes at Complainer University, I majored in the back in my day, Gripe. Back in my day,

I walked to and from the outdoor toilet, bare foot, both ways, in the snow, uphill. Our toilet paper was old newspapers. You whippersnappers with your indoor plumbing and your soft, quilted toilet paper,

don't know how good you have it. And back in my day, I swear there were bigger animals. I remember

the neighborhood cats being a lot more intimidating, particularly pumas. One time I saw

raccoon the size of a Rottweiler.

Huh. That makes me wonder if animals used to be bigger way far back in time, like when dinosaurs walked the earth.

And my friend Harrison was wondering too.

I think a lot of times we think about the dinosaurs as being gigantic animals or animals like woolly mammoths being like bigger than anything on earth right now.

My name is Christy Curry Rogers and I'm a paleontologist and a professor at McAllister College in St. Paul, Minnesota.

I study all kinds of extinct organisms that used to live on Earth but are no longer with us. And I think it's also really important to

remember that in the past, there were a lot of small animals. And sometimes we don't think about

those little animals when we kind of imagine the

dinosaur world. We kind of focus our attention just on the big things. But I think it's really

important to remember that on Earth right now, we have gigantic animals in the form of whales,

...