Field of Science


On the Road with the Shambulance

Hello from the land of boxes!

I'm about to move across the country, so there will be a brief hiatus from new stories here. But in the meantime, please enjoy some travel-themed reruns.

The Shambulance is a vehicle with an identity crisis (it might travel by land, sea, or space, and is potentially horse-drawn). It's also a series on this blog examining dubious health fads. Below, you'll find its complete voyages.

It has been, I think you'll agree, a twisted journey.

* * * * * * * * * * * * * * *

Ionic Foot Detox Baths (June 2012)
Hint: Don't.

Ab Toning Belts (or, Muscle Tone Is All in Your Head) (July 2012)
This goofy infomercial product blew my mind. But not because it works.

Zero-Calorie Noodles? (August 2012)
The only Inkfish post ever to involve a taste test.

Infrared Body Wraps (September 2012)
Be glad this doesn't work.

5 Reasons Not to "Cleanse" Your Colon (October 2012)
#3: It's rude to firehose your friends.

Copying Roger Clemens Won't Help You Lose Holiday Pounds (November 2012)
The dirt on vitamin B12 shots.

Enough Already with the Juice Cleanses (January 2013)
In which a salesperson suggests I fast for five straight weeks.

Deer Antlers Are Not Unicorn Horns (February 2013)
Some professional athletes are confused about this.

Reflexology and Other Stories (April 2013)
Non-traditional non-Chinese medicine.

Laser Lipo Only Kind of Sucks (July 2013)
Surprisingly, the least sketchy place the Shambulance has traveled.

If you'd like to suggest a future destination for the Shambulance to drive, climb, dive, or teleport to, leave your suggestion in the comments!

Image: taken by me with my iPhone because we already packed the camera cord.

Fish Grow Big Fake Eyes When Predators Are Near

If you're a young, edible animal, a little flexibility about how you develop can save your behind. Or, if you're a damselfish, it can get a few bites taken out of your behind but ultimately save your life.

The damselfish Pomacentrus amboinensis lives on coral reefs in the western Pacific, where it spends its days nibbling algae and trying to avoid being swallowed. As juveniles, these small fish have a pronounced eyespot toward the back of their bodies—a cartoonish false eye drawn on the body, like you might see on a butterfly's wing. Normally, the eyespot fades as the fish matures.

Researchers from James Cook University in Australia and the University of Saskatchewan in Canada asked just how flexible damselfish are while those false eyes are fading away. Can fish opt to keep their false eyes in certain situations? And if they do, does this not-very-subtle disguise actually do anything to protect them?

The scientists raised damselfish in tanks divided into compartments. Some damselfish lived alongside a natural predator of theirs: Pseudochromis fuscus, the "dusky dottyback." Thanks to the special tanks' clear windows and shared water, the young damselfish could see and smell the predator all the time. Other damselfish were raised on their own, or in tanks shared with a harmless vegetarian fish.

After maturing for six weeks in their respective tanks, the fish showed some clear differences. Compared to the other fish, damselfish that had lived near predators had larger false eyes. And their real eyes—startlingly to the scientists—were actually smaller.

"I was very surprised by the result," says lead author Oona Lonnstedt, a PhD student at James Cook University. "It just goes to show the lengths small prey will go to minimize predator attention on their front end."

This assumes that the point of all this camouflaging—growing a big fake eye near your tail and minimizing the actual eyes on your face—is to focus predators' attention on the wrong end of your body. The researchers didn't test predatory fish to see which part of a damselfish they chomped down on. But they did put the damselfish from their experiment onto isolated reef patches in the wild to see how they fared.

Within two days, up to half of the control fish (those raised alone or with non-predators) had disappeared from the reefs, and were presumed eaten. Damselfish that had grown up in a tank with predators, though, radically outperformed the others. Four days after being released onto the reefs, 90% of them were still alive and well.

Their large eyespots and minimized eyes may have made predators chase their back end, where a bite isn't as fatal as one to the head. These fish had also grown up taller in the spine-to-belly dimension, which gives an added challenge to hunters limited by the size of their mouths (and may give the damselfish better bursts of speed too). In the lab, these fish were less active and spent more time hiding; their reticence may also have helped them survive in the wild.

There's a trade-off happening, Lonnstedt says. Damselfish that live with predators and grow large false eyes also have stunted eye growth, which probably impairs their vision. It's not bad enough, though, to keep them from avoiding predators on the reef. In the end, being flexible about how their bodies develop allows them to survive and swim another day.

Image: Lonnstedt et al. (The fish on top grew up in the predator tank.)

Lönnstedt OM, McCormick MI, & Chivers DP (2013). Predator-induced changes in the growth of eyes and false eyespots. Scientific reports, 3 PMID: 23887772

Multitaskers Make the Best Lovers, Say Tree Frogs

It's not an impossible demand. It's just that a male tree frog can choose to spend his energy doing one thing or another thing, and females prefer that he does more of both. The best multitasker might be allowed to fertilize her eggs.

"The males gather in ponds in the evening and begin to call," says University of Minnesota ecologist Jessica Ward, setting the scene. The species in question is called Cope's gray tree frog. Next, she says, females come to the pond and spend a few minutes listening to nearby males. Then they choose for mates the ones whose calls they find most attractive.

What's attractive? There are a couple of ways a Cope's gray tree frog can make his song stand out from others in a chorus. The frogs can increase the speed of their calls, making more trills per minute. Or they might make each one of those trills last longer.

Ward and her colleagues set out to test whether male frogs can only devote energy to one of these factors at a time. And, they asked, are females more attracted to "multitaskers" who can manage both at once?

By haunting parks in the middle of the night with recording equipment, the researchers captured a thousand total calls from 50 different frogs. They found that males who called more often made shorter calls, and those who called less often made longer calls. In other words, there's a trade-off: when a frog puts more energy into one aspect of his song, he has to skimp elsewhere.

Next, the researchers interrupted male and female frogs that were already clasped together to do the deed and carried them back to the lab. The females were put into sound chambers, where they heard two different male frog songs at a time and could choose one to approach. The artificially generated songs had varying call lengths and speeds. Female frogs, it turned out, preferred the songs that had the best combination of long and frequent calls: the more male effort a song would have required, the more a female liked it.

Male frogs, meanwhile, were put into a kind of competition. They sat in a sound chamber and trilled away first on their own, then while hearing the sound of other frogs singing. Males adjusted their own songs when their neighbors were singing at the same time, making each call longer. But they also called less frequently, so the total amount of effort they put into each call stayed the same.

Males may already be expending almost all the effort they can to sing, Wade says. She thinks males who can make their calls faster and longer at the same time are somehow more fit than others. A study in a related species showed that frogs who put more effort into their calls were better swimmers, for example. So females may be onto something when they choose the male with the most difficult song to father their eggs.

This type of multitasking, where a tradeoff exists between different aspects of an animal's performance, has also been studied in birds. Wade says this is the first multitasking study in frogs. Though it's tempting to imagine humans caught in our own version of this trap—asked to attend to an impossible number of factors at once to be maximally attractive—Wade thinks of a different species next. "The multitasking hypothesis may also apply to some spiders," she says.

Image: Cope's gray treefrog by Geoff Gallice (via Flickr)

Jessica L. Ward, Elliot K. Love, Alejandro Vélez, Nathan P. Buerkle, Lisa R. O'Bryan, & Mark A. Bee (2013). Multitasking males and multiplicative females: dynamic signalling and receiver preferences in Cope's grey treefrog Animal Behaviour, 86 (2), 231-243 DOI: 10.1016/j.anbehav.2013.05.016

12 Things I Found Exploring the California Seafloor (and You Can Too)

If for some reason you haven't been invited on a submersible ride-along, the next best thing is probably 340 miles' worth of raw video footage from the ocean floor.

The U.S. Geological Survey just released a whole mess of data from its California Seafloor Mapping Program. Together with many partners, it's working on building maps of the California coast that include seafloor depth, habitat type, and other geological features. There's also video footage from cameras towed a few feet above the seafloor, as well as 87,000 still photos taken at regular intervals.

At the project's website, visitors can explore an interactive map that's layered with whichever types of data interest them. I know somebody out there is into bathymetry, but I opted to explore the library of photos and videos. Below is a selection of things I spotted. 

The videos are kind of tedious but will reward the patient viewer with an occasional sea cucumber or alarmed fish. And the up-and-down bouncing of the camera as it travels over the seafloor might induce seasickness, so I'm guessing it's a realistic experience. If I ever get that invitation, I'll let you know.

Local color.

Cauliflower trees (disclaimer: I am not a marine biologist)...

...which the camera smashed into.


Crabs making friends with starfish.

An ex-starfish? Note the impression in the ground. Maybe it got friendly with the wrong arthropod.

Further evidence for my theory that at the bottom of the sea, everything is either terrifying...

...or shaped like a penis. (What? I edit a kids' science magazine. YOU try finding a photograph of a bone-eating worm that's appropriate for 12-year-olds. Go Google it right now. I'll wait.)

We crashed into the ground again. Maybe the little crabs that keep scurrying away from the camera have the right idea.

Fodder for the future BuzzFeed article "45 Ocean-Floor Animals That Are Totally Waving Hello."

And something incognito. Does anyone know what it is?

Golden, Nadine E., & Cochrane, Guy R. (2013). California Seafloor Mapping Program video and photograph portal U.S. Geological Survey data set : 10.5066F7J1015K

Images: Golden, Nadine E., and Cochrane, Guy R., 2013, California Seafloor Mapping Program video and photograph portal. U.S. Geological Survey data set, doi.10.5066F7J1015K

Gibbon Moms Help Daughters Practice Their Singing for Future Mates

Before their daughters grow up and leave home, mothers may impart some lessons in the womanly arts—for example, the proper way to whoop and hoot with your mate while sitting in a tree branch. As an adult, a female gibbon sings elaborate duets with her male partner. But before she leaves the family, her mother seems to take responsibility for the daughter's vocal lessons.

Young gibbons spend many years learning to vocalize like adults. By age six or so, "sub-adult" apes can match the vocal prowess of a grownup. Mothers and daughters often sing at the same time, though it's not clear why. Researchers traveled into the rainforests of Sumatra to make audio recordings of gibbon families and try to figure out whether these sing-alongs are significant.

Lead author Hiroki Koda of Kyoto University and his colleagues studied six families of agile gibbons (that's a species name, not just a descriptor). Koda explains that gibbons are monogamous, and male and female young grow up with their parents before departing the group to find their own partners. Each family in the study included a nearly adult daughter, and the researchers captured recordings of these daughters and their mothers singing together.

They found that some daughter gibbons were better than others at singing in sync with their mothers. They were also better at matching their mothers' tunes. But these talented daughters actually duetted with their mothers less often. Koda thinks that's because the ones who "showed more skillful songs" are the most mature, and are nearly ready to leave home. Daughters who still need the practice sing with their mothers more often.

Here, a mother and daughter gibbon match each other's calls as they sing together:

The researchers also found that mothers who sing more often with their daughters—the ones who are still giving lessons—modify their own songs more when they do so. Koda says this may be similar to the "motherese" that humans speak to their babies. Like human moms talking slowly and at a high pitch, gibbon moms alter their vocalizations when duetting with their daughters.

Koda says that in the past, primate calls have been seen as "completely different from human language development." Rather than learning from their parents, young monkeys and apes seem to figure out their calls on their own. But this is the first evidence of mothers helping offspring learn to vocalize in gibbons—or any other nonhuman primate.

By paying more attention to vocal interactions between parents and offspring, Koda thinks scientists might discover other examples of primate parents getting involved in their children's learning. (After that, maybe they'll discover primate parents getting too involved. "Don't you take that tone with me, young lady! I heard what you just hooted!")

Images: Top, singing gibbon by patries71, via Flickr (not, as far as I know, the study species). Bottom, a mother gibbon from the study by Hiroki Koda.

Hiroki Koda, Alban Lemasson, Chisako Oyakawa, Rizaldi, Joko Pamungkas, & Nobuo Masataka (2013). Possible Role of Mother-Daughter Vocal Interactions on the Development of Species-Specific Song in Gibbons PLOS ONE DOI: 10.1371/journal.pone.0071432

Why Yellowstone's Grizzlies Should Be Grateful for Wolves

There's only one time a giant domino chain isn't fun: when you're a domino. Humans are great knockers-down of ecosystem domino chains, and sometimes we don't even know which species we've felled until we start propping things back up. When we knocked every last wolf out of Yellowstone National Park, for example, we didn't know how we were hitting bears at the other end of the chain.

When Yellowstone was first created, visitors were free to kill the animals. Then in the early 20th century, government "predator control" efforts gradually finished the job of wiping out the park's wolves. The last ones were killed in 1926. Wolves remained absent from Yellowstone until the mid-1990s, when officials lugged pens of them into the park and set them free.

William Ripple, an ecologist at Oregon State University, and his colleagues investigated how the return of wolves affected grizzly bears in Yellowstone. They compared data from old studies of bear scat to data collected after the wolves came back. Specifically, they wanted to know how many berries bears had been eating.

What do wolves have to do with berries? Nothing. But wolves kill elk—and elk eat all kinds of plants, including berry shrubs that bears would otherwise dine on.

For a few decades after wolves were wiped out of Yellowstone, the booming elk population was culled to keep it under control. But the elk culling ended in the 1960s. Ripple found that in the late 1960s, while the elk population was still low, bears had a relatively high percentage of fruit in their dung. Over the next 20 years, as the elk population more than tripled, the grizzlies' berry diet dropped to almost nothing. And in the late 2000s, after wolves had reestablished themselves in the park and elk numbers had dropped, a hearty helping of berries returned to bear diets.

The researchers also looked at berries themselves, choosing a representative plant called serviceberry. They saw that plants in fenced-off areas (where elk and other grazers can't reach them) had been growing for decades. Outside the fences, though, the berry plants were young—they had all sprung up after wolf reintroduction. The evidence all pointed the same way: more wolves means fewer elk, which means more berries, which means better-fed bears.

Berries are good for a grizzly's diet, the authors explain, because bears use them to fatten up before entering hibernation. Female bears will give birth during their winter doze, so having enough energy stored is crucial to the population's survival.

Ripple says there's not yet any evidence that having more berries in their diets is actually helping bears—his study didn't ask that question. But he is optimistic about the future of grizzlies in Yellowstone. "It is good to see that the bears can at times get significant calories from...the berries," he says. Berries made up as much as 39% of female grizzlies' diets in recent years.

Other studies have shown that beaver and bison numbers both increased after wolves came back to the park. This might be, the authors write, because herbivores have less competition now from the once-ubiquitous elk. All the species that were knocked down while the wolves were gone can now stand back up and give them a thank-you.

Images: Grizzly bear and wolf at Yellowstone from YellowstoneNPS (via Flickr); diagram from Ripple et al.; bear hug card from OldEnglishCo on Etsy (available for $4.71!).

William J. Ripple, Robert L. Beschta, Jennifer K. Fortin, & Charles T. Robbins (2013). Trophic cascades from wolves to grizzly bears in Yellowstone Journal of Animal Ecology DOI: 10.1111/1365-2656.12123

Fish Fear Robotic Predators, Unless They're Drunk

Scientists swear they had a really good reason for building a robotic fish, getting some other fish drunk, and then chasing them around with it.

The robotic bird head, too.

Researchers at the Polytechnic Institute of New York University and the Istituto Superiore di Sanità in Rome were interested in zebrafish. These thumb-sized, striped fish are laboratory favorites because their genome is well understood, they reproduce quickly, and their embryos are totally transparent.

One area of research that employs zebrafish is the study of emotions, including anxiety and fear. Outside of a lab, people may not spend much time pondering fish anxiety. But study coauthor Simone Macrì of the Istituto Superiore di Sanità says zebrafish can help unravel complex environmental and genetic interactions, such as emotion, because their genetics are not a mystery. Their simple brains are useful for "clarifying some fundamental aspects [of] emotions," he says.

It's easy to spook a little fish; all you have to do is show it a predator. But wrangling live predatory animals such as birds or other fish is inconvenient. It also adds an unwanted variable to an experiment, since your predator may not behave consistently (or may have moods of its own). So Macrì and his colleagues wondered if they could build robotic predators good enough to be stand-ins in these experiments.

They carefully crafted robots that looked like a natural zebrafish enemy, the Indian leaf fish. ("The visual appearance of the robotic fish was obtained by spray-painting the robot with an ivory base color followed by the hand painting of brown color patterns typical for this species," the authors write—in case this is a project you want to try at home—"as well as the attachment of small plastic eyes.") A motor let the robot fish wave their tails at various speeds. There was also a robotic heron head that plunged toward the water as if hunting.

To find out whether their robots made the same impression on zebrafish as a real predator, the researchers let the animals meet each other. Sure enough, zebrafish swam to the far side of their tank when a robotic leaf fish was in the water. When a robotic heron struck from above, zebrafish darted under a shelter.

Then, to make sure the fish were responding to the robots out of fear or anxiety, the researchers gave the zebrafish a drug that reduces anxiety: alcohol. After letting their subjects swim around in ethanol-spiked water, the researchers gave them the same tests. Now they didn't flee the robot fish and were slow to seek shelter after the robotic heron attack.

As the researchers had hoped, sober fish feared robotic predators, and alcohol lessened those fears. The results are published in PLOS ONE.

Macrì thinks this technique could help researchers who study anxiety with zebrafish improve their methods. As long as scientists are looking at simple behaviors, he says, "the robots are ideally suited." And after being chased by a giant robotic predator, zebrafish might need a drink anyway.

Images: left by Azul, via Wikimedia Commons; right Cianca et al. (In reality, the robotic fish were several times larger than the zebrafish.)

Valentina Cianca, Tiziana Bartolini, Maurizio Porfiri, & Simone Macrì (2013). A Robotics-Based Behavioral Paradigm to Measure Anxiety-Related Responses in Zebrafish PLOS ONE DOI: 10.1371/journal.pone.0069661

Man Develops Synesthesia after Stroke, Finds James Bond Theme "Orgasmic"

It wasn't only James Bond. Nine months after suffering a stroke, a 45-year-old happened to notice that the wailing horns in a Bond movie's opening credits gave him strange, ecstatic feelings. But any high-pitched brass instrumentals would do the trick. A musical segment during the Beijing Olympics gave him the same feelings. The man's doctors came to realize that when his brain rebuilt itself after the stroke, he had developed synesthesia.

Associating letters or numbers with specific colors is the most common kind of synesthesia. Other sensory combinations, like experiencing tastes when hearing certain sounds, are rarer. In some cases, colors, sounds, or other sensations may trigger emotions.

The recovered stroke victim, whom doctors and researchers at St. Michael's hospital in Toronto described in the journal Neurology, turned out to have more than one trigger for his emotional synesthesia. High-pitched horns gave him very good feelings, but words written in the color blue made him feel "disgusted." Yellow words were also disgusting, though a little less so.

To confirm what the patient said he was experiencing, the authors did fMRI scans of his brain, along with six non-synesthetic subjects of the same age. All the subjects listened to the Bond theme in the scanner, and their brain activity was compared to what happened when they heard a solo euphonium—a tuba-like instrument that didn't excite the patient at all.

Control subjects responded to the Bond theme no differently than the euphonium, but the stroke victim's brain had a much stronger response to the theme song. The activity in his brain, spread out across many different areas, fit with "intense emotional arousal," the authors write, "rather than simply...a pleasant musical experience." Apparently, the music really was sending him to double-oh-heaven.

In the scanner, subjects also viewed blocks of text written in yellow, blue, or black. While control subjects' brains didn't respond differently to the different colors, the synesthetic man's brain did. His neural activity when reading blue or yellow words suggested he was processing an emotional stimulus, the authors say.

There's only been one other case recorded of someone developing synesthesia in mid-life. That person's experience—a tingling sensation when hearing certain sounds—also came after a stroke. Both patients had damage in the same region of their brains: the thalamus. Tom Schweizer, director of neuroscience research at St. Michael's hospital and the lead author of the paper, says this is significant.

Schweizer describes the walnut-sized thalamus as a "central relay station" for the brain. It's densely packed with fibers that connect neurons in different brain regions. Schweizer thinks that in trying to repair itself after the stroke, the thalamus may have gotten some wires crossed.

The patient's synesthesia isn't exactly like traditional synesthesia, which develops in childhood. For example, he's able to suppress his feelings if he tries, while synesthesia is usually defined as involuntary. Nevertheless, Schweizer says this case "could be a rare window" into how synesthesia develops and the role the thalamus might play.

Even the authors of the study couldn't resist a Bond pun, titling their paper "From the Thalamus with Love." (Why not "License to Thrill"? Or "Dr. No...More Jokes Please; Don't You Know This Makes It Really Awkward When People Invite Me to Jazz Concerts?") Yet his case gives a serious clue as to how the brain's wires can get double-crossed.

Image: Paul-W (via Flickr)

Tom A. Schweizer, PhD, Zeyu Li, BSc, Corinne E. Fischer, MD, Michael P. Alexander, MD, Stephen D. Smith, PhD, Simon J. Graham, PhD, & Luis Fornazarri, MD (2013). From the thalamus with love: A rare window into the locus of emotional synesthesia Neurology DOI: 10.1212/WNL.0b013e31829d86cc