Today you’ll learn about how scientists are developing a form of birth control for men, why humans need more sleep during the winter, and how whales are giving up singing their love songs in favor of fighting for mates.
Today you’ll learn about how scientists are developing a form of birth control for men, why humans need more sleep during the winter, and how whales are giving up singing their love songs in favor of fighting for mates.
Male Contraceptive
Winter Snooze
Whale Fight Songs
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Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/male-contraceptive-winter-snooze-whale-fight-songs
[SFX: INTRO MUSIC/WHOOSH]
NATE: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you’re learnin’ super cool stuff. I’m Nate.
CALLI: And I’m Calli. If you’re dropping in for the first time, welcome to Curiosity, where we aim to blow your mind by helping you to grow your mind. If you’re a loyal listener, welcome back!
NATE: Today you’ll learn about how scientists are developing a form of birth control for men, why humans need more sleep during the winter, and how whales are giving up singing their love songs in favor of fighting for mates.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
NATE: Calli, have you heard this super common phrase: learn something new everyday and you’ll never work a day in your life.
CALLI: Um, yeah, duh, obviously. That’s why I’ve dedicated my life to the quest of knowledge!
NATE: So has Gary Arnt, host of the podcast Everything Everywhere Daily.
CALLI: Omg I love that show, I listen most days… some days… a few days a week. Listen, there’s just so much good information that Gary almost always sends me down a curiosity rabbit hole and before I know it the entire day is gone.
NATE: Well if you, dear listener, don’t have time to go with Calli down the rabbit holes of learning, Everything Everywhere Daily is a great place to start. In just ten minutes each weekday you can learn something new.
CALLI: About history, geography, mathematics - even science. It’s a great companion to Curiosity Daily.
NATE: The Curiosity team has been listening to episodes about Why Are There No Flying Cars and The Most Important Supermarket Trip in Human History around here, and we think you’ll love them too!
CALLI: Check the show out and spend a little time - or a few hours - learning something new today.
NATE: CTA: Learn something new every single day with Everything Everywhere Daily—find it on Apple Podcasts, Spotify, or wherever you get your podcasts!
[SFX: WHOOSH]
CALLI: Birth control has had a ton of issues that women have to go through, and there has been a push for years to develop a birth control for men. We've actually discussed a few different options on the show before, but new research suggests there may be a new birth control that will exist for men soon.
NATE: Okay, that would be great if we get that figured out. Tell me more about the new discoveries.
CALLI: All right. Birth control is something that has existed in one form or another for over 3000 years. And yet it's not perfect because accidental impregnation is still a challenge many women have to face. And this is a challenge that is mostly left up to women. To women have birth control pills, birth control patches, birth control inserts, IUDs, hormone therapy, birth control shots, cervical caps, abstinence, and even the removal of our uteruses, just to name a few. Then, on the other hand, have condoms and abstinence. That's about it.
NATE: Also, vasectomies. But. Oh, yeah, yeah, yeah. Might be end of list.
CALLI: Yeah, that's what I mean. There has been an imbalance for years, and finally science is doing something to address that. And it all started with the creation of a non-hormonal male contraceptive that actually works.
NATE: Okay, that sounds great. Tell me more.
CALLI: Well, it all started with the creation of an inhibitor molecule that was designed to attack a specific protein in men known as a soluble adenylyl cyclase, or SAC for short. SAC is the protein in men's bodies that, simply put, make sperm move the inhibitor molecule. These men designed in theory would make it so sperm do not move. And this isn't permanent. It's just for a little while and then the sperm would be back to business.
NATE: Okay, I maybe need a little more context here. Why? Why does it matter if the sperm doesn't move? I mean, wouldn't the presence of sperm in sexual intercourse still be enough to impregnate somebody?
CALLI: Now is as good a time as any to get into this. Let me tell you how sperm actually works during intercourse. prior to ejaculation, sperm can be found in a dormant state in a part of the scrotum known as the cauda epididymis. In order to activate and expel or ejaculate the sperm, they have to mix with semen. Certain compounds in the semen make SAC kick start into gear and begin the process of fertilization. Best way I can describe this is like a race car. The sperm needs to move really, really fast in order to cross the finish line. In order to move fast, the car needs gas. The SAC is the gas that will get the sperm across the finish line. And in this case, the finish line is the egg.
NATE: Okay, so the sperm are cars. The SAC is the gas. That's right.
CALLI: Yeah, you got it. So the team tested their compound on sperm samples extracted from mice. First, they isolated one set of sperm from a male mouse's testes and another from a female mouse's vagina After intercourse. They applied the inhibitor to each set, immobilizing them completely for two and a half hours. At around 3 hours in the sperm began moving, but at a much slower pace before returning to their normal speeds at the 24 hour mark.
NATE: Okay. But you said these were samples extracted from mice, meaning it's sort of a petri dish style experiment. Right? And did they tested on actual mice? And more importantly, would it work on humans?
CALLI: They wanted to make sure. So they injected groups of mice with the compound and found that 52 male mice exposed to the inhibitor anywhere between 30 and 150 minutes before copulation were completely unable to impregnate female mice. Then they tested it on an additional 45 mice with the range of time extended to as far as 180 minutes. Unfortunately, one pregnancy did occur at that time.
NATE: Wait. Out of all of them was like one pregnancy out of 97 mice.
CALLI: Yeah, exactly. And in comparison, they had 50 other mice in the experiment who weren't exposed to the inhibitor. And within a two hour window, 15 of those mice impregnated female mice. That difference is pretty huge. And it set the researchers on a course to begin developing this inhibitor as a pill you could take with a meal. Research is still, as usual, very early, though, and the researchers still need to test the contraceptive on other animals before they can even test it on humans. But still, they have hopes that this could be the first step towards sexual partners being able to make contraceptive decisions from a more fair and balanced playing field.
NATE: It's going to cause men to have mild tummy aches, and so they're just going to scrap the whole thing.
CALLI: You're not wrong.
[SFX: WHOOSH]
NATE: I don't know about you, but to me, it's a lot harder to get out of bed when it's cold in the winter. And it turns out there's actually some scientific reasoning for that.
CALLI: I mean, yeah, that's because it's cold and it's dark and my bed is warm, and I'm not going to leave it.
NATE: Spoken like a true scientist. I appreciate that. But you're not entirely wrong. So a recent study saw a team of scientists recruit patients who live in urban areas into sleep studies known as polysomnographies. And this is a long word for a test that's used to diagnose sleep disorders. A polysomnography records your brainwaves the oxygen level in your blood and your heart rate and breathing during sleep while also measuring eye and leg movements. And during the test, they had 188 patients sleep naturally in a special lab with no alarm clock.
CALLI: Okay. I want to know what a special lab looks like for sleeping. But what did they find?
NATE: Interestingly, people get and need more sleep during the winter than any other time of the year. The average was about an hour longer across the board. This was somewhat expected because there's less sunlight in the winter, which means more melatonin being produced in our bodies. And melatonin is the chemical in our bodies that naturally regulates our sleep cycles. The more important thing they found is that patients get up to 30 minutes more rapid eye movement or REM sleep in the winter, which is actually a huge difference.
CALLI: 30 minutes versus an hour. Why would 30 minutes of REM sleep be huge?
NATE: REM sleep is important because it's the sleep that helps us dream. And since dreaming is how we process the memories of our day, something we've discussed in other episodes is how we strengthen our memories. REM sleep is directly linked to our circadian rhythms, which are our bodies, internal clocks. And the researchers now believe that the absence of sunlight in the winter could be contributing to an increase of REM sleep, which means that our memories become more strongly formed in the winter than any other time of year. And also, remember, these participants all come from urban environments which see higher levels of noise and light, which are things that decrease melatonin and therefore the chance of REM sleep.
CALLI: Wait, I am not familiar with this. Why do noise and light affect melatonin?
NATE: Melatonin is best developed in complete darkness. Have you ever slept in complete darkness, like, say, a cabin in the woods and just woke up right when the sun came out? And that's your body's natural clock working the way it's supposed to. What this study is supposing is that the sun being out much less frequently during the winter is actually helping us get better REM sleep, even if we live in urban environments.
CALLI: So what's the bigger picture here? Because we're just talking about like urban environments right now?
NATE: Well, the researchers say that if this study's findings can be replicated in people with healthy sleep patterns, this would actually make for the first ever evidence that humans need to adjust their sleep habits seasonally. For example, they recommended that we all collectively need to go to bed earlier in the winter. And all in all, this study shows that at a bare minimum, there's a very real chance that no matter how much trouble we have getting a good night's sleep, we're more likely to have one in the winter.
CALLI: All right. I'm going back to bed.
NATE: Convincing stuff.
[SFX: WHOOSH]
CALLI: I don't want to anthropomorphize too much, but it's actually kind of sad that some whales have given up singing their whale love songs for fighting instead.
NATE: Why?
CALLI: Yeah.
NATE: Why is this happening?
CALLI: Well, this is coming from researchers studying whales off the coast of Australia's eastern seaboard. Associate Professor Rebecca Dunlop from the University of Queensland School of Biological Sciences did research analyzing almost two decades of data on the humpback whale behavior and discovered something interesting. Male whales aren't singing the way they used to to attract potential mates. Instead, they're actually fighting other male whales for the attention of female whales.
NATE: Why did they stop singing? They lose their whale karaoke machines?
CALLI: I'm going to back up a little bit because I've got to paint the bigger picture for you to understand. We've talked a little bit on the show about whaling, and that's the act of poachers killing and stripping whales for their parts for financial gain. But what we haven't talked about is how in the 1960s whaling hit an all time high at its peak. Over 80,000 whales were being hunted and killed per year. This actually affected whale populations so deeply that whaling declined because we just couldn't find any more whales over time. Technological advances led to more sustainable substitutes for whale oil and bone in cosmetics and food and textile industries. So whaling went out of fashion, and as whales started to come back into the world, some researchers believed that singing might have become evolutionarily unviable, so to speak, because Whale Song not only attracts other males to compete for female attention, it could also attract whalers.
NATE: Okay, so this is some kind of adaptive evolutionary response.
CALLI: It could be, but there are a few reasons. The first reason is practical. If an area is more heavily populated, that means there are more whales. And if there are more whales, then Whale Song could potentially direct them to the place where male whales are singing for the attention of a female whale.
NATE: Meaning that they can easily find their competition.
CALLI: Exactly. Back in 1997, when the university's dataset began, Whale Song was the dominant way to attract mates in the community. Within just 17 years, that changed, and the reason might have a lot to do with the population growth. In 1997, there were 3700 whales. By 2015, 27,000. That being said, recorded instances of Whale song were already on the decline by 1997. So this might not paint the full picture.
NATE: Okay, so what is it about fighting that could attract females?
CALLI: It's actually not so much that fighting is attractive as much as the absence of whale song makes it tougher for the female whale to pick her mate. Some male whales get lucky and find a single and ready to mingle female whale that hasn't already mated with other males. But in most cases, multiple males have to vie for the attention of a single female. And when that happens, a competition is born.
NATE: What kind of competition for whales?
CALLI: A competition of physical aggression and unmatched straight boxing? Yeah, I mean, kind of. If a bunch of male whales are on the scene and are trying to mate, they'll start ramming, they start charging the even try to, like, slap each other with their own heads. And whales, as smart as they are, know that every single action they take is putting their own life at risk. Therefore, the question arises: is it worth it? Which means we now see certain male whales actually give up the pursuit of a romantic relationship because the means to get into one could actually kill him.
NATE: Okay, so what's the bigger picture for the whales here?
CALLI: Well, this means that with one study, we've witnessed a complete shift in the social dynamic among wild creatures. Things like this just don't really happen too often in the animal kingdom, but the combination of a yo yo whale decline in growth, and whales having to adapt to a new social hierarchy might have forced these changes to come sooner than they might have through evolution. It's really actually not clear at all what the long term problems or benefits to this will be for whale populations. But on the other hand, it's a fascinating look into the socialization of a certain kind of whale and a look into what creatures other than humans will do, all in the name of love.
NATE: I'll be concerned if John Legend takes up Prizefighting, I guess.
CALLI: Yeah.
NATE: It's pretty much not to imply anything about Mr. Legend's body type. Of course.
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up.
CALLI: The world of birth control is a very unbalanced one when it comes to methods deployed between men and women, but that could become a thing of the past with the invention of a new birth control method - for men! Nearly 100% of pregnancies were prevented in a lab model performed on mice, and now testing is underway for other animal models. No word on when humans can get their hands on this, but soon, birth control will have a much more even playing field than it did before!
NATE: A new study has revealed that humans get better sleep in the winter! Specifically, the lack of sunlight in the harsh winter months might be contributing to our REM sleep patterns - the sleep associated with the creation and retention of memories. Research is still early on this one, but if repeated on healthy sleepers, it might prove that we all need to change our sleep schedules every season!
CALLI: Would you fight harder than you’ve ever fought for the one you love? If you said yes, you’re in good company - because researchers have discovered that certain whales off the coast of Australia have given up whalesong when it comes to mating and have replaced it with a FIGHTIN’ SPIRIT. It’s not clear how this will affect the whale populations long term, but it’s a fascinating look into the socialization of whales who would fight for anything - even love.