Good morning, John.

Recently, I got extremely lucky and was invited for a behind   the scenes tour of the Denver Zoo. As it turns out, the night keeper of the zoo, and yes, that's a real thing,   is a huge Nerdfighter.

Like, huge, huge.  Was wearing a NerdCon Nerdfighteria hoodie and had your face on her shoelaces, huge. Basically, we're everywhere, including at the zoo at night. And I learned so much on this tour that I would now like to tell you  the top 17 coolest things that I learned on my behind the scenes tour of the Denver Zoo.

In no particular order. John, elephants can get tuberculosis. The same kind that people can get.  So people can give it to elephants and elephants can give it to people.

Sumatra, which I don't think very much about, is the 6th largest island in the world  and has its own elephant and tiger and orangutan that exists there and nowhere else. This fish and I took this video,  got a CT scan because it was listing to the side and no one was sure why. Turns out it had gas, like, intestinal gas.

Now, whenever it starts to go sideways,  they feed it some peas and that fixes it. Penguins love to chase flies. Some rhinos are from areas of the world with very little iron.

So rhinos that live a long time in other places that don't have very little iron will eat, like,  the grass and other stuff that  grows in their enclosures,  and that will result in,  like, the opposite of anemia. They have to keep this big, beautiful man on a low iron diet,  but sometimes his iron levels will get too high, and when that happens,  they have to take the iron out of him, literally, by just removing a bunch of his blood. Hank (off camera): "Oh, it's just dirt."  Katherine: "It's a big--no.

No, it's definitely got poop in it."

Hank: There are freshwater stingrays. Duh. The Denver zoo has a walk in freezer  full of anti-venom and actually serves as a local supply and national supply  because sometimes people get bitten by their, like, exotic pet snakes. And then they call the zoo up and they're like, do you got one of those?

And then the zoo just, like, gives them their anti-venom for free. Like, there's, like, rules  where you can't sell it,  so they have to give it away and then buy more for themselves. That's not one of the reasons why I thought it would be good to have zoos, but there it is.  Adult lake Titicaca frogs do not breathe.  They have little lungs inside of them that are atrophied and never used.

They breathe 100% through their skin, they look like that. I mean, they're kind of cute--  but also kind of not. Also very strange,  possibly because they look a little bit like certain parts of the male anatomy,  they get like blended up and drunk as smoothies to increase health.

It doesn't work. The Denver Zoo had a king cobra that  got cancer scale cancer, like skin cancer of a snake. They biopsied it, confirmed it was cancer, did surgery to remove the cancerous area,  and then gave adjuvant chemotherapy, actually a chemotherapy drug that humans also get,  except humans don't usually have it put inside of a ratio before they take it.

Wild sheep and goats often live in areas without minerals in the soil. And so they will congregate in parking lots  to find the salt transported either on cars or left behind when people pee,  because, as we once learned, they crave that mineral. I have been told that flamingos are pink because they eat pink shrimp.

But that's kind of wrong. These are two different species of flamingos  that are fed the exact same diet, and one is way more pink than another. And juveniles are basically not pink at all.

They are not pink because they eat shrimp. They can be pink because they eat shrimp. They could just poop out the pink compounds.  They're pink because it's evolutionarily advantageous to be pink.

Przewalski's Horse is not pronounced like that.  It's pronounced Schavalsky's Horse. The Przewalsky's horse is the   last surviving species of non domesticated horse. It very nearly went extinct,  but was brought back through  captive breeding programs.

And now they are once again roaming Mongolia. Also as part of that effort,  a Przewalski's Horse embryo was implanted in a domesticated horse and was born and is alive  and is named Kurt and is in San Diego, which-- that sounds great!  This is actually raising hopes that we might one day be able to bring back species  that are extinct but have close living relatives. Like black rhinos,  male elephants have a hormonal cycle, and that leads to something called must.

And when they are in must, they're super angry and irritable,  in part because glands swell up on the sides of their head until the stinky oils  start oozing through their thick skin, which we think probably hurts quite badly. Every year, this boy vulture, who was raised in captivity,  builds a giant, beautiful nest. And then this female vulture,  who was rescued from the wild with a broken wing, very deliberately lays her egg in a tiny   pile of sticks a few feet away.

I didn't learn anything new about giraffes mostly. Cause I, like, know a lot about giraffes,  but I did get touch one and feed  it and be really close to it,  and that was amazing. Thank you so much to everybody at the Denver Zoo who took a little bit of time to talk with me.

People who are working all across the world doing conservation efforts  and trying to make life easier for animals,  especially to Dissa and  Erica for showing us around. John, I'll see you on Tuesday. Also, the first issue of our newsletter.

We're Here, went out today.  I hope people like it. There's lots of opportunities to email us  through the newsletter, share stuff with us, be collaborative. We do not want this to be  like a one way newsletter.

This is going to be a every  directional newsletter.  And among the many things we talk about in that newsletter is,  John, your new video on tuberculosis. It's on the Crash Course channel, an entirely new crash course format  where we give somebody a chance to give a lecture. John, you're just the guinea pig.

I'm looking forward to seeing   who comes next. It won't be me. Though I do want to do one.

Tacking this onto the end because we just sent out the newsletter. So if you want to check your email for it, if you don't see it,   you can check your spam folder or just search for Hank and John. Or, We're in your Inbox, I think is the title of the email,  and then you can reply to that if you want to.

And we will get that email if you reply to it.  Because if you reply to it, your spam filter will be kinder   to it in the future. Okay, bye.