Learn about why you eat differently when you’re stressed; how humpback whales use “bubble nets” to catch fish; and the surprising genetic reason why females outlive males.
Learn about why you eat differently when you’re stressed; how humpback whales use “bubble nets” to catch fish; and the surprising genetic reason why females outlive males.
Why do we eat differently when stressed? by Steffie Drucker
Humpback whales use 'bubble nets' to catch fish by Cameron Duke
The surprising genetic reason females outlive males by Cameron Duke
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/why-stress-makes-you-eat-differently-humpback-whales-hunt-with-bubble-nets-and-the-surprising-genetic-reason-females-outlive-males
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about why you eat differently when you’re stressed; how humpback whales use “bubble nets” to catch fish; and the surprising genetic reason why females outlive males.
CODY: Let’s satisfy some curiosity.
We eat differently when we’re stressed, and you’re about to learn why. We figured now might be a good time to talk about this, since the Coronavirus pandemic has turned life as we know it upside down. And let’s face it: your eating habits are likely among the many things about daily living that have dramatically changed. Maybe you’re snacking all day, accidentally devouring the groceries that were supposed to last another week. Or maybe you’re hardly eating at all. So what’s the deal? Why are we eating so differently right now?
Well, one thing to realize is that we’re all under a lot of stress, and like I said before, stress levels play a big role in our eating habits. When your fight or flight response kicks in and boosts your adrenaline levels, your body figures food digestion is a waste of energy. As a result, it hits pause on the whole process. It’s why you might feel sick to your stomach before an important exam or a big performance. Or a livestreamed press briefing.
But the longer the stress lasts, the more your body produces another stress hormone called cortisol. Research suggests that high cortisol levels over the long term can mess with levels of metabolic hormones like insulin and leptin, which can make your hunger signals go out of whack. At the same time, it may knock your brain’s reward system off balance, which makes fatty, sugar-filled foods even more desirable. These types of food can provide momentary comfort, but they can ruin your mood in the long run.
This is especially true if you realize you’re stress eating and then beat yourself up about it. One study found that the more people worried about restraining their eating, the more they ate under stress. If this sounds like you, the first step is to acknowledge your stress and notice how it’s changing your behavior. Then, set up your environment so you need less restraint — meaning, buy fewer packaged snacks and put healthier options like fruits and vegetables out in the open.
And if you’re not eating enough, try a calorie-rich drink like a protein shake.
Stress could also be having indirect effects on your eating habits. If anxiety is keeping you up at night, you may be sleep-deprived — and that’s been shown to increase hunger levels. If you’re cooped up inside, it’s harder to exercise regularly, and that itself can make it harder to manage stress.
Those acts of self care are usually the first to slip in times of stress — true self care like getting enough sleep, not things like shopping or getting a massage. But that will only lead to a vicious cycle that leaves you more and more stressed. So give yourself a break, take the pressure off of your eating habits for a bit, and do what you can to relax. One thing’s for sure: you are definitely not alone.
If you wanted to catch a lot of fish at once, you’d probably use a net, right? Well, humpback whales use nets, too. Bubble nets. Yes, bubble nets — hollow columns of bubbles they use to corral fish. Wanna learn about bubble nets? Of course you want to learn about bubble nets. Literally who would not want to learn about bubble nets? I dunno. Let’s do this.
The whale starts by taking a deep breath and diving underwater. When it gets low enough, it starts swimming in circles while blowing out through its blowhole, which creates an upward spiral of shimmering bubbles. If you were flying above the ocean’s surface and looking down, you’d notice a white ring of seltzer-sized bubbles bursting at the surface. But down below, krill and herring suddenly find themselves trapped in a vertical tunnel with walls made of roiling, turbulent water. The bubble walls create an impenetrable barrier for tiny plankton and a disorienting visual obstruction for larger fish. The result: they’re trapped.
To keep the prey exactly where they want ‘em, the whales then do what scientists call “pectoral herding.” That is, they use their pectoral flippers to literally herd the prey into their mouths and to keep the bubble net from collapsing. In what’s called vertical pectoral herding, they swim to the base of the tunnel, then swim up through it with their flippers outstretched like they’re coming in for a hug. Then they use their flippers to funnel prey into their open mouths. With horizontal pectoral herding, they guide prey ever closer by splashing the surface of the water with their pectoral flippers to make a tighter tunnel within the larger one.
Humpback whales aren’t the only whales that eat by swimming with their mouths open like giant pool skimmers, but they are some of the only whales that trap their prey in bubble nets. Bubble nets take a lot of precise maneuvering that not all whales can master. But humpbacks have streamlined bodies, extra-large tails, and long, wide flippers fringed with bumps that help reduce drag in the water. And that makes it easier for them to make sharp turns and quick maneuvers.
Scientists have only seen this behavior in the wild a handful of times because of how hard it is to observe whale behavior in the first place. But the consistent way the whales make bubble nets suggests this is probably a pretty common hunting behavior. Now if you’ll excuse me, I’m going to make like a baleen whale and guide some unsuspecting snacks into my mouth.
There’s a surprising genetic reason women tend to outlive men.
The fact that men have shorter lifespans than women do is not exactly news. But the reasons you’ve probably heard may not play as big of a role as you might thing — stuff like the male tendency toward more aggression or more dangerous jobs. Recent research puts the blame on sex chromosomes themselves. When it comes to lifespan, the X and Y chromosomes that male animals inherit from their parents may put them at a genetic disadvantage.
For a little refresher, the human genome is made of 46 strings of DNA called chromosomes. And two of those are sex chromosomes. In humans, chromosomal females are the homogametic sex, meaning that they have two of the same sex chromosome: X. Chromosomal males the heterogametic sex, meaning that they get two different sex chromosomes — one X chromosome and one Y chromosome.
A recent study examined lifespan data for 229 species from across the tree of life that all have chromosomal sex determination like humans do. In their analysis, they found that the homogametic sex lives, on average, 17.6% longer than the heterogametic sex. So what’s so great about having two of the same sex chromosome? One word: redundancy.
Here’s the issue. There are a lot of genes on the X chromosome, and a lot of them have nothing to do with sex characteristics. For example, the gene that gives us the ability to see color is on the X chromosome. If a female of a species inherits a harmful trait on one X chromosome, like a faulty color vision gene, it’s not always a big deal since the other X chromosome might have a healthy copy of the gene. No harm done.
Males, on the other hand, get only get one X chromosome. That means one chance. They don’t have a backup for faulty genes because the Y chromosome is really small and doesn’t have much to contribute, other than some genes that help release extra testosterone during development. So, while females have a backup X chromosome as insurance, males are stuck with the one they have. This makes males more likely to express potentially harmful X chromosome traits. That includes red-green colorblindness, along with more serious recessive diseases like Fragile X syndrome and Duchenne [due-SHEN or due-SHANE] muscular dystrophy.
This trend holds up regardless of differences between sexes. Birds, for example, have an inverted chromosome system from mammals – for them, females are the heterogametic species. As a result, males of these species outlive females on average, regardless of differences in behavior or which bird jobs they choose. Variety may be the spice of life, but redundancy is what lengthens it.
Let’s do a quick recap of what we learned today
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CODY: Today’s stories were written by Steffie Drucker and Cameron Duke, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Today’s episode was produced and edited by Cody Gough.
CODY: Join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!