Learn about the medical history of using leeches; potty training cows to help the environment; and the math behind eggs. More from zoologist Bill Schutt: Pick up "Pump: A Natural History of the Heart" https://www.workman.com/products/pump Website: https://billschutt.com/ Follow @BillSchuttBooks on Twitter: https://twitter.com/BillSchuttBooks Facebook: https://www.facebook.com/BillSchutt1/ Potty training cows can help the environment by Steffie Drucker BORENSTEIN, S. (2021, September 13). No bull: Scientists potty train cows to use “MooLoo.” ABC News; ABC News. https://abcnews.go.com/Weird/wireStory/bull-scientists-potty-train-cows-mooloo-79991165 Dirksen, N., Langbein, J., Schrader, L., Puppe, B., Elliffe, D., Siebert, K., Röttgen, V., & Matthews, L. (2021). Learned control of urinary reflexes in cattle to help reduce greenhouse gas emissions. Current Biology, 31(17), R1033–R1034. https://doi.org/10.1016/j.cub.2021.07.011 Researchers are toilet-training cows to reduce ammonia emissions caused by their waste. (2021, September 13). EurekAlert! https://www.eurekalert.org/news-releases/927878 Scientists have uncovered the mathematical formula for the shape of an egg by Briana Brownell Research finally reveals ancient universal equation for the shape of an egg. (2021, August 31). News Centre - University of Kent. https://www.kent.ac.uk/news/science/29620/research-finally-reveals-ancient-universal-equation-for-the-shape-of-an-egg Narushin, V. G., Romanov, M. N., & Griffin, D. K. (2021). Egg and math: introducing a universal formula for egg shape. Annals of the New York Academy of Sciences. https://doi.org/10.1111/nyas.14680 Who Laid The First Egg? Scientists Move A Step Closer To Linking Embryos Of Earth’s First Animals To Adult Form. (2021). ScienceDaily. https://www.sciencedaily.com/releases/2004/11/041104005307.htm Follow Curiosity Daily on your favorite podcast app to learn something new every day withCody Gough andAshley Hamer. Still curious? Get exclusive science shows, nature documentaries, and more real-life entertainment on discovery+! Go to https://discoveryplus.com/curiosity to start your 7-day free trial. discovery+ is currently only available for US subscribers.
Learn about the medical history of using leeches; potty training cows to help the environment; and the math behind eggs.
More from zoologist Bill Schutt:
Potty training cows can help the environment by Steffie Drucker
Scientists have uncovered the mathematical formula for the shape of an egg by Briana Brownell
Follow Curiosity Daily on your favorite podcast app to learn something new every day with Cody Gough and Ashley Hamer. Still curious? Get exclusive science shows, nature documentaries, and more real-life entertainment on discovery+! Go to https://discoveryplus.com/curiosity to start your 7-day free trial. discovery+ is currently only available for US subscribers.
Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/leeches-in-medicine-potty-training-cows-the-math-of-eggs
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 the history of using leeches for medical purposes, with help from zoologist Bill Schutt; how potty training cows can help the environment; and why it’s a big deal that scientists finally figured out the mathematical formula for the shape of an egg.
CODY: Let’s satisfy some curiosity.
Bill Schutt - Why did we ever use leeches? (Cody)
You probably knew that people used to use leeches for medical purposes. What you might not know is that we're still using them today — and for a pretty surprising reason. Halloween is just around the corner, which is why we've got a guest today who's known for diving into the science of the macabre. Bill Schutt is a zoologist at the American Museum of Natural History who's written about everything from cannibalism to blood feeding. His new book is entitled "Pump: A Natural History of the Heart." And in it, he explains why people started using leeches in medicine — and why they still do today. Here's Bill.
[CLIP 3:41]
Who knew that leeches were so handy in reattachment surgery? I certainly didn't. Again, that was Bill Schutt, a zoologist at the American Museum of Natural History and author of the new book "Pump: A Natural History of the Heart." Bill will be back tomorrow to talk about giraffes and their truly bizarre circulatory systems.
Potty training cows can help the environment by Steffie Drucker (Ashley)
Puppies get housebroken and kittens are taught to use litter boxes. So why can’t barnyard animals be trained to do their business in a designated place? It might sound like a silly question, but it led to a serious study aimed at curbing the effects of climate change. And it turns out that cows? They can be potty-trained.
Here’s why this is important. It’s well-known that cows contribute to climate change with their methane-rich farts and burps. But you can’t train a cow not to belch — it’ll explode. The gas has to go somewhere! But gas isn’t the only problem. Cow urine has high levels of nitrogen, which turns into ammonia when combined with feces. Ammonia can kill plants and its vapors are toxic to livestock. And when it seeps into the soil, microbes turn it into nitrous oxide, which is a potent greenhouse gas. Nitrates in the urine can also contaminate groundwater and make people sick.
So, scientists wondered if they could collect and treat the pee before it could cause any problems. This is no small feat — a single cow produces about 8 gallons or 30 liters of urine a DAY! Old MacDonald’s farm is absolutely covered with pee-i-e-i-o.
The team attempted toilet training with 16 calves, using a custom-built bovine bathroom dubbed the “MooLoo.” Picture a rectangular stall with saloon-style doors and a patch of AstroTurf for the floor. They started by confining a calf to the MooLoo until it let flow. Every success was rewarded with a sweet treat. 10 out of 16 mastered it right away. In two subsequent experiments, the calves were allowed to roam an indoor area with access to the MooLoo via an alleyway. If they used the MooLoo in this scenario, they got another treat. But if they couldn’t make it, they got an unpleasant squirt of water, just like how you’d train a house pet. 11 of the 16 calves learned to use the latrine for the majority of their bathroom breaks.
What’s even more impressive is that these baby bovines mastered the task in only 15 days. Some human toddlers take way longer to toilet train! The researchers hope they can increase their success rate in future studies, and maybe one day, every cow will be potty trained.
Scientists have uncovered the mathematical formula for the shape of an egg by Briana Brownell (Cody)
What makes an egg… egg-shaped? Scientists and engineers have been trying to find a precise mathematical answer for decades, and a team of researchers from Kent have finally… cracked it.
If you thought we already knew the mathematical formula for the shape of an egg, then it sounds to me like you counted your chickens before they hatched. But I don’t blame you for thinking that, since the shape of an egg has been described as “perfect.” After all, it has some pretty impressive properties.
Eggs need to be large enough to be able to hold the embryo as it develops. For that, a sphere should be the perfect shape. It would maximize the egg’s interior volume with the smallest surface area of shell around it. This minimizes the heat that’s lost, which means it takes less energy to incubate, and it’s less affected by temperature changes.
A sphere is also pretty tough, and hard to crack. That means it’s good for keeping the chick safe inside.
Some eggs are spherical, but not all. That’s because a sphere is so strong that it’s hard for the chick to eventually break out of the egg. Instead, other eggs take on a slightly elliptical shape that gives the egg overall strength along with a slightly weaker part that allows the egg to crack in two.
Not so fast though. Both spherical and elliptical eggs can easily roll away. Not ideal, especially for the many birds that lay eggs on rocky cliffs.
So to solve this problem, the eggs of many bird species evolved to be ovoid — in other words, slightly uneven on one side compared to the other. This means that if the egg starts to roll, it will actually move in a circle. You can try this at home with a chicken egg.
We already had a mathematical formula for all of these egg shapes — spherical, oval, and ovoid.
But there’s a fourth shape that had stumped scientists. Many eggs are slightly conical, or pyriform. Basically, they look a little pear-shaped, like an ovoid egg with a pointier top. And we didn’t have a formula for that shape. That was the team’s big breakthrough: to calculate the pyriform shape, they came up with a mathematical model that added a new function onto the formula for the ovoid shape. With that, they had a universal formula for any egg’s shape.
The new formula will allow scientists to classify and study the various kinds of eggs. And it might also be useful in engineering too, as architects use biologically-inspired shapes to create strong and beautiful structures.
That’s definitely Egg-cellent news.
RECAP
Let’s do a quick recap of what we learned today
1. ASHLEY: Doctors have been using leeches for thousands of years. In the ancient world, there was a belief that people had four humors, and one of them was blood — so leeches were used to draw blood to quote-unquote “balance the humors.” People stopped using leeches for a while after we discovered bacteria and pathogens. But in the 1960s, surgeons realized they could use leeches to help people recover after reattachment surgery. Talk about a surprising surgical tool!
2. CODY: Cows can be potty trained. Scientists wanted to find a way to cut down on the emissions and pollution caused by cow pee, so they tried teaching 16 calves to use a bovine bathroom they called the MooLoo. 11 of the calves mastered the task in just about two weeks — way faster than some human toddlers!
3. ASHLEY: Scientists have come up with a universal formula for any egg shape. We had formulas for spherical, oval, and ovoid eggs before, but with a tweak to the ovoid shape they were able to calculate pyriform, or pear-shaped eggs, too — and that means, pretty much any egg in existence.
a. Aside: For the record, the egg came before the chicken. In 1998, in China, fossilized embryos of coral-like animals were found in China. The embryos were in various stages of development inside of an egg. They were dated to 600 million years ago.
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ASHLEY: Today’s writers were Steffie Drucker and Briana Brownell.
CODY: Our managing editor is Ashley Hamer, who was also an audio editor on today’s episode. ASHLEY: Our producer and lead audio editor is Cody Gough.
CODY: [AD LIB SOMETHING FUNNY] Join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!