John: Good morning, Hank. It's Monday.

Hank, it's no secret that the three most viewed videos on the Vlogbrothers channel feature, in order: giraffe sex, giraffe sex, and giraffe sex.

And yet, Hank, it recently occurred to me that, in spite of all of this, we have never actually made a video about... giraffe sex. A shortcoming I intend to rectify today.

So, Hank, not to call you out, but the other day on Twitter, you Tweeted an image that you designed. Now, Hank, let's put aside the question of why you, a busy professional spend your free time coming up with cute images of giraffe love. This would make a great T-shirt, and so, it is a great T-shirt. Hank, Nerdfighters, that shirt is available for pre-order right now at dftba.com, link in the doobly-doo.

But anyway Hank, your illustration of giraffe love may be adorable, but it completely belies the truth about giraffe mating. Which is that it is profoundly non-romantic. To begin with Hank, giraffes are extremely promiscuous. And when I say extremely promiscuous, I mean they rarely mate with the same person twice, in fact they don't mate with people at all, they mate with giraffes. Although that reminds me of a Yahoo! Answers question that I wanted to read to you. "Are male giraffes gay/homosexual, I heard that they were, and if they are, would they be interested in male humans, my friend was asking, and I said that I would find out for him?"

Hank, pardon me for a moment, I need to use the desk really quickly.

Ahh, head-desk.

Oh, Internet, what disturbing question won't you ask. Well, Hank to answer that question on behalf of someone's non-existent friend, almost all male giraffes are bisexual. In fact, researchers believe that 90% of total giraffe sex is male giraffes having sex with male giraffes, and that 1% of total giraffe sex is females having sex with females. Meaning that just about 9% of giraffe sex is heterosexual. And that's really no wonder, Hank, because their heterosexual sex is .

So, Hank, I present to you the majestic giraffe. [To giraffe picture] Stop looking at me that way, I know your secrets.

Giraffe mating involves a process called flehmen or possibly flehmen, I don't know how to pronounce it, and I don't want to learn. Basically male giraffes don't really like hooking up with female giraffes unless they're ovulating, so to find out if they're ovulating, they use their faces to smack the female giraffes in the bottom. Which causes the female giraffes to pee, if they happen to like the male giraffe, they'll pee a bunch. And then the male giraffe drinks the pee to find out if it tastes like it's time to party.

Hank, I will remind you, I am not the pervert here, I am just reporting the facts. He's [the giraffe] the pervert.

Then, if the pee smells right, and the lady's still into it, there's a courtship process, which mostly involves the male giraffe trying to hump the female giraffe and the female giraffe running away. Until finally, coitus occurs, lasting up to, several seconds. Then the mommy giraffes are pregnant for 400 freaking days, no wonder they try to run away. And the male giraffe just goes on his merry way, hooking up with dudes and smackin' pee out of girls. I wish I were making this up.

So, anyway Hank, the long and short of it is that the animal kingdom is rarely as romantic as we'd like it to be. But there is one super cute thing about giraffes. As seen in your image, they neck a lot. And for a long time biologists thought this was a way of fighting, but it turns out that while it is sometimes a way of fighting, it's also kind of a way of hugging. So the shirt isn't a lie, it's just an oversimplification. Like, someday when Henry asks me, "How is it that baby giraffes come into the world?" I will put on this shirt and I will say, "Henry, this shirt was designed by your uncle Hank to answer that very question. As this helpful diagram shows, when giraffes neck, there is a heart that forms in the space between their necks, and that heart is a baby giraffe."

Thus ends our introduction to giraffe mating habits. There's a link to Hank's T-shirt in the doobly-doo.

Hank, thank you for designing that. I always forget that you're so talented. I know that sounds stupid, but every time I see something you've designed, I always think, "Wow, Hank is pretty, you know, good at stuff." That's about as close as brothers get to complimenting each other.

Hank, I'll see you on Wednesday.