For Pacific Mole Crabs It’s Dig or Die | Deep Look

Pacific mole crabs, also known as sand crabs, make their living just under the surface of the sand, where they’re safe from breaking waves and hungry birds. Some very special physics help them dig with astonishing speed.

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Among the surfers and beach-casting anglers, there’s a new visitor to San Francisco’s Ocean Beach shoreline.

Benjamin McInroe is there for only one reason — to find Pacific mole crabs, a creature commonly known as “sand crabs” — and the tiny animals whose burrowing causes millions of small bubbles to appear on the beach as the tide comes in and out.

McInroe is a graduate student from UC Berkeley studying biophysics. He wants to know what makes these little creatures so proficient at digging their way through the wet sand.

McInroe hopes that he can one day copy their techniques to build a new generation of digging robots.

— What are Pacific Mole Crabs?

Pacific mole crabs, also known as sand crabs, are crustaceans, related to shrimp and lobsters. They have four pairs of legs and one pair of specialized legs in the front called uropods that look like paddles for digging in sand. Pacific mole crabs burrow through wet sand and stick their antennae out to catch bits of kelp and other debris kicked up by the breaking waves.

— What makes those holes in the sand at the beach?

When the waves recede, mole crabs burrow down into the sand to keep from being exposed. They dig tail-first very quickly leaving holes in the wet sand. The holes bubble as water seeps into the holes and the air escapes.

— What do birds eat in the wet beach sand?

Shore birds like seagulls rush down the beach as the waves recede to catch mole crabs that haven’t burrowed down quickly enough to escape. The birds typically run or fly away as the next wave breaks and rolls in.

—+ Read the entire article on KQED Science:

https://ww2.kqed.org/science/2018/02/13/for-pacific-mole-crabs-its-dig-or-die/

—+ For more information:

Benjamin McInroe, a Ph.D. student at UC Berkeley, studies how Pacific mole crabs burrow
https://www.ocf.berkeley.edu/~bmcinroe/

Professor Robert Full directs the Poly-PEDAL Lab at UC Berkeley, where researchers study the physics of how animals and use that knowledge to build mechanical systems like robots based on their findings.
http://polypedal.berkeley.edu/

—+ More Great Deep Look episodes:

Decorator Crabs Make High Fashion at Low Tide | Deep Look
https://youtu.be/OwQcv7TyX04

These Fish Are All About Sex on the Beach | Deep Look
https://youtu.be/j5F3z1iP0Ic

Sea Urchins Pull Themselves Inside Out to be Reborn | Deep Look
https://youtu.be/ak2xqH5h0YY

There’s Something Very Fishy About These Trees … | Deep Look
https://www.youtube.com/watch?v=rZWiWh5acbE&t=1s

—+ See some great videos and documentaries from the PBS Digital Studios!

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https://www.youtube.com/watch?v=aOeFRg_1_Yg

Why Is Blue So Rare In Nature?
https://www.youtube.com/watch?v=3g246c6Bv58

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—+ About KQED

KQED, an NPR and PBS affiliate in San Francisco, CA, serves Northern California and beyond with a public-supported alternative to commercial TV, Radio and web media.

Funding for Deep Look is provided in part by PBS Digital Studios. Deep Look is a project of KQED Science, which is supported by the S. D. Bechtel, Jr. Foundation, the Dirk and Charlene Kabcenell Foundation, the Vadasz Family Foundation, the Gordon and Betty Moore Foundation, the Fuhs Family Foundation Fund and the members of KQED.

This Giant Plant Looks Like Raw Meat and Smells Like Dead Rat | Deep Look

With rows of Dr. Seuss-like flowers hidden deep inside, the corpse flower plays dead to lure some unusual pollinators.

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DEEP LOOK is a ultra-HD (4K) short video series created by KQED San Francisco and presented by PBS Digital Studios. See the unseen at the very edge of our visible world. Get a new perspective on our place in the universe and meet extraordinary new friends. Explore big scientific mysteries by going incredibly small.

* NEW VIDEOS EVERY OTHER TUESDAY! *

For a plant that emits an overpowering stench of rotting carcass, you’d think the corpse flower would have a PR problem.

But it’s quite the opposite: Anytime a corpse flower opens up at a botanical garden somewhere in the world visitors flock to catch a whiff and get a glimpse of the giant plant, which can grow up to 10 feet tall when it blooms and generally only does so every two to 10 years.

A corpse flower’s whole survival strategy is based on deception. It’s not a flower and it’s not a rotting dead animal, but it mimics both. Pollination remains out of sight, deep within the plant. KQED’s Deep Look staff was able to film inside a corpse flower, revealing the rarely-seen moment when the plant’s male flowers release glistening strings of pollen.

It’s not that the corpse flower is the only plant to attract pollinators like flies and beetles by putting out bad smells. Nor is it the only one that produces male and female flowers at the same time.

“The fact that it does all of this at this outsized scale – all of this together – is what’s so unique about it, biologically,” said Pati Vitt, senior scientist at the Chicago Botanic Garden.

When a titan arum is ready to flower, a stalk starts to grow out of the soil. Once it has reached four to 10 feet, a red “skirt” unfurls. Though it has the appearance of a petal, it’s really a modified leaf called a spathe that looks like a raw steak.

The yellow stalk underneath is called the spadix and it gives the plant its scientific name, Amorphophallus titanum, or roughly “giant deformed phallus.”

In its native Sumatra, the corpse flower opens for only 24 hours. In captivity, it often lasts longer. With just a day to reproduce, the stakes are high.

— How many chemicals make up the smell of the corpse flower?
More than 30 chemicals make up the scent of the corpse flower, according to the 2017 paper “Studies on the floral anatomy and scent chemistry of titan arum” by researchers at the University of Mississippi, University of Florida, Gainsville, and Anadolu University in Turkey:
http://journals.tubitak.gov.tr/botany/issues/bot-17-41-1/bot-41-1-6-1604-34.pdf

Some of the chemicals have a pleasant scent. But mostly, the corpse flower at first smells like funky cheese and rotting garlic, as a result of sulphur-smelling compounds. Hours later, the stink changes to what Vanessa Handley, at the University of California Botanical Garden at Berkeley describes as “dead rat in the walls of your house.”

—+ Read the entire article:
https://ww2.kqed.org/science/2018/01/23/this-giant-plant-looks-like-raw-meat-and-smells-like-dead-rat/

—+ For more information:
Great illustration on the lifecycle of the corpse flower by the Chicago Botanic Garden:
https://www.chicagobotanic.org/titan/faq

University of California Davis Botanical Conservatory:
http://greenhouse.ucdavis.edu/conservatory/

—+ More Great Deep Look episodes:

This Mushroom Starts Killing You Before You Even Realize It
https://www.youtube.com/watch?v=bl9aCH2QaQY

A Real Alien Invasion Is Coming to a Palm Tree Near You
https://www.youtube.com/watch?v=S6a3Q5DzeBM

—+ See some great videos and documentaries from PBS Digital Studios!

It’s Okay To Be Smart: How to Figure Out the Day of the Week For Any Date Ever
https://www.youtube.com/watch?v=714LTMNJy5M

Above The Noise: Can Genetically Engineered Mosquitoes Help Fight Disease?
https://www.youtube.com/watch?v=CB_h7aheAEM

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—+ About KQED

KQED, an NPR and PBS affiliate in San Francisco, CA, serves Northern California and beyond with a public-supported alternative to commercial TV, radio and web media.

Funding for Deep Look is provided in part by PBS Digital Studios. Deep Look is a project of KQED Science, which is supported by the S. D. Bechtel, Jr. Foundation, the Dirk and Charlene Kabcenell Foundation, the Vadasz Family Foundation, the Gordon and Betty Moore Foundation, the Fuhs Family Foundation Fund and the members of KQED.

Why the Male Black Widow is a Real Home Wrecker | Deep Look

Sure, the female black widow has a terrible reputation. But who’s the real victim here? Her male counterpart is a total jerk — and might just be getting what he deserves.

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DEEP LOOK: a new ultra-HD (4K) short video series created by KQED San Francisco and presented by PBS Digital Studios. See the unseen at the very edge of our visible world. Get a new perspective on our place in the universe and meet extraordinary new friends. Explore big scientific mysteries by going incredibly small.

We’ve all heard the stories. She mates and then kills. Her venom is 15 times stronger than a rattlesnake’s. One bite could kill you. With a shiny black color and a glaring red hourglass stomach, she has long inspired fear and awe.

But most species of widow spider (there are 31), including the western black widow found in the U.S., don’t kill their mates at all. Only two widow spider species always eat their mate, the Australian redback and the brown widow, an invasive species in California.

And the male seems to be asking for it. In both of these species, he offers himself to her, somersaulting into her mouth after copulation.

He may even deserve it. During peak mating season, thousands of males will prowl around looking for females. Females set up their webs, stay put and wait.

Once the male arrives at her silken abode, he starts to wreck it, systematically disassembling her web one strand at a time. In a process scientists call web reduction, he bunches it into a little ball and wraps it up with his own silk.

Then, while mating, he will wrap her in fine strands that researchers refer to as the bridal veil. He drapes his silk over her legs, where her smell receptors are most concentrated.

After all of that, he is most likely to crawl away, alive and unscathed.

— Why does the black widow spider eat her mate?

No one really knows, but scientists assume his body supplies her with nutrition for laying eggs. Sometimes she eats him by accident, not recognizing him as a mate.

— How harmful are black widows to people?

We couldn’t find a documented case of a human death from a black widow spider in the U.S., but a bite will make you sick with extreme flu-like symptoms. Luckily, black widows aren’t aggressive to people.

— Why do black widows have a red hourglass?

It’s a warning sign, a phenomenon common in nature that scientists call aposematicism, which is the use of color to ward off enemies.

—+ Read the entire article on KQED Science:

https://ww2.kqed.org/science/2018/01/09/why-the-male-black-widow-is-a-real-home-wrecker

—+ For more information:

Black widow researcher Catherine Scott’s website: http://spiderbytes.org/

—+ More Great Deep Look episodes:

Why Is The Very Hungry Caterpillar So Dang Hungry?
https://www.youtube.com/watch?v=el_lPd2oFV4

Everything You Never Wanted to Know About Snail Sex
https://www.youtube.com/watch?v=UOcLaI44TXA

—+ See some great videos and documentaries from the PBS Digital Studios!

Origin of Everything: Why Does Santa Wear Red?
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PBS Eons: ‘Living Fossils’ Aren’t Really a Thing
https://www.youtube.com/watch?v=mPvZj2KcjAY

—+ Follow KQED Science:

KQED Science: http://www.kqed.org/science
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—+ About KQED

KQED, an NPR and PBS affiliate based in San Francisco, serves the people of Northern California and beyond with a public-supported alternative to commercial media. Home to one of the most listened-to public radio station in the nation, one of the highest-rated public television services and an award-winning education program, KQED is also a leader and innovator in interactive media and technology, taking people of all ages on journeys of exploration — exposing them to new people, places and ideas.

Funding for Deep Look is provided in part by PBS Digital Studios and the John S. and James L. Knight Foundation. Deep Look is a project of KQED Science, which is supported by HopeLab, The David B. Gold Foundation; S. D. Bechtel, Jr. Foundation; The Dirk and Charlene Kabcenell Foundation; The Vadasz Family Foundation; Smart Family Foundation and the members of KQED.