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Science Friday

How Vampire Bats Evolved To Drink Blood, Ethics Checks On Brain Research, Cicada Exhibit. March 25, 2022, Part 2

Science Friday

Science Friday and WNYC Studios

Wnyc, Natural Sciences, Life Sciences, Friday, Science

4.4 • 6.3K Ratings

🗓️ 25 March 2022

⏱️ 47 minutes

🧾️ Download transcript

Summary

How Vampire Bats Evolved To Drink Blood

Vampire bats subsist solely on blood: In technical terms, they’re what’s called “obligate sanguivores.” And the three species of vampire bats are the only mammals to have ever evolved this particular diet.

Living on blood is hard work. Blood is a low-calorie food with a lot of water volume, and very little of it is fat or carbohydrates. To survive this lifestyle, vampire bats have made numerous physical adaptations—stretchy stomachs, tricks to deal with high amounts of iron, even specialized social systems related to sharing food.

But how, genetically, did they manage it? Guest host John Dankosky talks to Dr. Michael Hiller, co-author on new research published this week in Science Advances looking at some of the specific genes vampire bats lost in order to gain these unique abilities.

Difficult Brain Science Brings Difficult Ethical Questions

In recent weeks, we’ve told you about efforts to explore and map the human brain through tissue donations, and the troubling tale of a bionic eye implant startup that left users without tech support. The two stories point to different aspects of the rapidly advancing field of neuroscience—and each comes with its own set of ethical questions.

As humans advance in their ability to understand, interpret, and even modify the human brain, what ethical controls are in place to protect patients, guide research, and ensure equitable access to neural technologies?

John Dankosky talks with neurotech ethicist and strategist Karen Rommelfanger, the founder of the Institute of Neuroethics Think and Do Tank, about some of the big ethical questions in neuroscience—and how the field might try to address the challenges of this emerging technology.

The Brief And Wondrous Lives Of The Cicada

The Staten Island Museum in New York has been home to the eye-catching room full of insect art since 2021’s emergence of the Brood X cicadas. In bell jars and cabinet drawers and under glass display cases, colorful cicadas from species around the world participate in scenes of human-like activities—they read miniature books, arrange dried flowers, create textile art, converse with animal skulls, lounge on and in jelly jars, and more. It’s all part of artist Jennifer Angus’ exhibition “Magicicada,” an homage to our reliance on the insect world.

Producer Christie Taylor talks to Angus and Staten Island Museum entomologist Colleen Evans about the wonder of insects. Plus, how art and science can complement each other and teach even the most bug-shy visitor to appreciate the natural world.

Transcript

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0:00.0

This is Science Friday. I'm John Dankoski. Ira is away.

0:04.6

Later this hour we'll talk about the ethics of research on brains. But first, do you shudder at the

0:10.4

thought of a blood-drinking vampire bat? Pretty creepy, right? Well, it turns out that a diet of

0:16.0

blood isn't exactly the best way to eat. And so, vampire bats have to consume more than their

0:22.2

bodies weight in blood every single night. In fact, vampire bats are the only mammals on earth where

0:28.1

blood is the only thing on the menu. So, how do they evolve to rely on this nocturnal

0:34.2

nourishment? My next guest went looking at their genes for clues and found some surprising changes.

0:41.2

Dr. Michael Hiller is professor of comparative genomics at the Center for Translational

0:46.0

Biodiversity Genomics. He's based in Frank for Germany. Welcome to Science Friday, Dr. Hiller,

0:51.2

thanks for being here. I know. So, we've talked about vampire bats in the show before. In fact,

0:55.6

they're one of our charismatic creatures that we've spoken of. But tell us how does drinking blood

1:01.5

require vampire bats to be different from other bats? So, drinking blood is a very unique diet

1:08.0

that among mammals evolved only once in this lineage that comprises these three living vampire

1:15.0

bats species. And so, blood is, as you already said, not a really good diet. It has a low caloric

1:21.9

value. Most of it is fluid. Of the nutrients, most of what these vampire bats get is protein.

1:28.8

So, it's really a challenge to live and survive with such a diet. Typically, you need sugars,

1:35.6

for example, to nourish your brain and other organs. Fatty acid are very powerful,

1:42.4

or very energy-rich nutrients. And proteins are not so much. So, it challenges really that

1:48.8

these vampire bats get these highly biased diets. So, essentially, of the dry mass of blood,

1:56.2

people estimate about 93% is protein, and only about 1% each is carbohydrates,

2:02.5

so sugars and fat. They have to drink an awful lot of blood to get what they need to be able to

2:09.2

survive, to fly around all night. Yeah, that's right. This is something they likely need to

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