The Lonely Dinosaurs

This story was inspired by yesterday’s New York Times article about a pair of fossil dinosaur skeletons that are going up for auction. The two dinos may have died locked in combat, and they could each be new kinds of dinosaurs, both traits that would make them incredibly important from a scientific perspective. But if they end up in a private collection, paleontologists may never get a chance to study them. I couldn’t help thinking, though, about how lonely the pair would get.

The men left, carrying away the wooden box and packing peanuts, the tape and the tools, closing the door and dimming the lights, leaving behind two fossil dinosaurs, half stuck in the rock where they had rested for millions of years.

“Hello, there,” said a big white bird. It was a dodo, stuffed. “Welcome to the Collection.”

“What? Where are we?” one of the dinosaurs asked. He glanced around. The room was cavernous. On three walls were two levels of shelves made of a rich, dark wood. Most were packed with books, leather and gold trimmed. Some were fronted with glass, enclosing treasures, like jade statues and odd-colored stones and one-of-a-kind gadgets. The fourth wall was all windows, with overstuffed chairs poised to look out over an expanse of green.

“The Collection,” the dodo repeated. “I’m so glad to have company. It’s been so quiet here. I’m Dee. What are you called?”

“Hmm,” the dinosaur said. “Well, I’m a Nanotryannus, so I suppose you can call me Nanny. My friend here is a Chasmosaurine.”

“Call me Chaz.”

The dodo hopped down from her shelf and walked around the pair. “You can’t move out of that rock, can you?” she asked.

“No,” said Chaz. “We’ve been stuck like this for forever.”

“Pity. There’s an ancient bowling game around here somewhere. It would be nice to have someone to play against,” Dee said. “I haven’t had any friends since I left the museum.”

“Museum? What’s that?” asked Nanny.

“Oh, you didn’t come from the museum? I used to live in one. It was kind of like the Collection, but fewer books and more stuff, especially stuff like you and me,” Dee explained. “And during the day lots of humans would come and visit. I miss the little ones. Even if they were noisy and screamed sometimes. It’s so quiet here. No one ever visits. Only the cleaning lady.”

“We got bought in an auction,” said Chaz. “We overheard one of the moving guys talking about it while we were in the box. He said we cost millions of dollars.”

“What are dollars?” Nanny wondered.

“He also said that a rich guy bought us,” Chaz went on. “But I don’t know what that means.”

“The rich guy owns everything in the Collection,” Dee said. “Including you and me. But he never comes here. I’ve only seen him once. He brought in someone who took lots of pictures. Hasn’t been back since. Do you like Asimov?”

“Asimov? What’s that?” Nanny asked.

“Isaac. Author. There’s first editions of all his works here,” Dee said. “I’m currently working my way through them. I read Darwin and Austen last year. Newton the year before that. Or if you don’t like science fiction, we could try Tolstoy. I could read aloud to you. Since you can’t bowl.”

“I suppose it’s better than what we have been doing,” Nanny said.

“Which was nothing,” Chaz muttered.

“Though I liked your description of a museum,” Nanny said. “I should have liked to have gone to one. Maybe met other dinosaurs like me.”

“It could be worse. We could be alone,” said Chaz. “We might not be able to move, but at least we’re together. And now we’ve got Dee.”

“So,” Dee said, “Asimov is OK then?”

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Image from the Natural History Museum in London courtesy of flickr user Kit

July 31, 2013Permalink 1 Comment

Yellowstone Wolves Good For Grizzlies

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The reintroduction of wolves to Yellowstone National Park, starting in 1995, has had some good effects on the food web there: The wolves keep the elk population in check, and with fewer elks to graze on the vegetation, plants including aspen and willows have rebounded. There’s further evidence that this greater availability of plants has been a boon to the beaver and bison populations in the park.

Now comes a study, just published in the Journal of Animal Ecology, that shows that grizzly bears have also gotten a boost to their diet from the wolves’ return.

Yellowstone grizzly bears are a bit different than grizzlies elsewhere — they don’t eat many berries. Studies of the bears that were conducted in the late 20th century found that Yellowstone grizzlies had some of the lowest berry consumption in the interior of North America. That was a bit weird because from July to October, female grizzlies usually gorge on the fleshy fruits. Berry calories can be easily converted to and stored as fat, perfect for bulking up for the long hibernation as well as the pregnancy and birth that usually take place during winter.

“Wild fruit is typically an important part of grizzly bear diet,” William Ripple, an ecologist at Oregon State University and coauthor on the new study, said in a statement. “At certain times of the year [berries] can be more than half their diet in many places in North America.”

Ripple and his colleagues have been studying how the reintroduction of wolves to Yellowstone has affected the Yellowstone food web, and they thought that the berry situation for the Yellowstone grizzlies might have changed with wolves’ return. The issue is more than just a note of academic interest. After the wolf population reached sufficient numbers that the government wasn’t worried they’d die out, the wolves were removed from the endangered species list in 2011, letting hunting of them start up again. If it turns out that the wolves have an impact on other endangered critters, such as grizzly bears, conservationists might have a better case for stopping the hunt.

Since asking grizzly bears to complete a survey of their diet isn’t exactly practical, the researchers analyzed bear poop, comparing scat collected from 2007 to 2009 with data from 1968 to 1987. That latter time was one when elk were increasing in numbers (they went from 3,000 in 1968 to 19,000 in 1994) and bears weren’t doing so well. The bears lost their easy meals in 1971 when the park closed all of its garbage dumps. That led to a lot more bear-human conflicts, and many bears were removed or killed. By 1975 the grizzlies were listed as threatened.

The team found that the percentage of fruit in bear scat declined from 1968 to 1987, as the elk were increasing. But after the wolves had come back into the picture, the bears began eating a lot more berries. In August, for example, the male diet was as much as 29 percent fruit and a female’s up to 39 percent.

What’s happening is that with fewer elk to munch on the park’s vegetation, the berry plants can thrive and bears can eat their fill. It’s likely that other critters, including birds and rodents, are benefiting from the recovering fruit harvest as well, the researchers say.

“Studies like this also point to the need for an ecologically effective number of wolves,” study coauthor Robert Beschta, of Oregon State University, said in a statement. “As we learn more about the cascading effects they have on ecosystems, the issue may be more than having just enough individual wolves so they can survive as a species. In some situations, we may wish to consider the numbers necessary to help control overbrowsing, allow tree and shrub recovery, and restore ecosystem health.”

Photo courtesy of Yellowstone National Park

July 29, 2013Permalink Leave a comment

Fish Feels Its Way With Fins

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Cartoon animators have got it right — fish really do use their fins for more than just swimming. Or at least bluegill sunfish (Lepomis machrochirus) do. They use their pectoral fins — those are the ones on the sides — to reach out and touch obstacles, helping them to navigate. That’s the finding from a new study from two Harvard biologists published in the Journal of Experimental Biology.

Bluegill sunfish may be familiar because they’re the a popular sportfish in the eastern United States. Throw out a hook with a worm into the local lake, and you might just catch yourself a bluegill supper.

These fish live in the littoral zone, close to shore, an area that can be full of vegetation that the fish have to navigate through. The fish have decent vision, and they also have help from their lateral line, a special organ that helps detects movement and vibration in the water.

But maybe the fish have another way to help them spot obstacles in the water, the Harvard team thought. The researchers began by creating an obstacle course for the fish, with evenly spaced acrylic tubes in a big tank. Then they filmed fish swimming through the tank. To cut off the fish’s vision, they turned out the lights. To disable its lateral line, they treated the fish with cobalt chloride.

The scientists had hypothesized that only when its others senses were disabled would the fish reach out with their fins. To their surprise, however, the fish used their fins to touch the acrylic tubes even when they could see and/or use their lateral line. The bluegill sunfish would use their pectoral fins to propel themselves forward between posts, but they would also wrap those same fins around the obstacles.

“Fish did not appear to push off of the posts to change heading or move forward. Forward motion did not initiate until the beat following the tapping contact with the obstacle posts,” the researchers write.

The pectoral fins act a bit like our arms while we’re swimming, propelling and steering a fish through the water and helping it to feel its way through the weeds.

Image from U.S. Fish and Wildlife Service, via Wikimedia

July 25, 2013Permalink Leave a comment

The Smell Of A Corpse Flower? Meh

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Even up close, the titan arum doesn’t look real. But I didn’t wait in a long line outside the U.S. Botanic Garden just to see the plant. I wanted to smell it — would the “corpse flower” live up to its name?

No.

Not that I’ve ever smelled a corpse and could compare that. But I’ve encountered enough other awful scents (trash rotting in a heat wave, burned brakes on a Metro train, a New York City sidewalk) to know that this one was not too bad. A fellow visitor said that the scent reminded him of fish rotting on the seashore. I got a whiff of really bad body odor (which could have been just really bad b.o. — everyone is pretty gross and smelly this time of year in D.C.). It was much less than I was expecting, and less than others expected as well. Perhaps the plant had already dispensed the nastiest of its smells before I got there.

The titan arum employs its rotten scent as a lure for insect pollinators. Researchers have determined that a chemical called dimethyl trisulfide is responsible for the smell. Dimethyl trisulfide is also produced during the cooking of onions and leeks, as well as in the early decomposition of a human body; so corpse flower is actually an accurate term.

For me, though, it was the flower’s size — eight feet tall — that was really amazing. The plant looked more like a prop for a sci-fi movie than something you’d find here on earth. But the flower can be found growing in the wild, in the forests of Sumatra in Indonesia. And I suppose that, compared to the tame vegetation around Washington, Sumatra would appear to be other-worldly.

One weird thing I discovered today, though, is that titan arum isn’t the plant’s real name. It’s scientific name is Amorphophallus titanum. (The genus name means “misshapen phallus.”) The name titan arum was made up by famed BBC presenter David Attenborough — he didn’t think that saying Amorphophallus made for appropriate television and came up with the alternative. The name stuck.

Image by the author

July 23, 2013Permalink Leave a comment

The Iberian Lynx Is Doomed — Maybe

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The world’s most endangered cat is not the lion or cheetah or tiger; it’s the Iberian lynx. Already at risk for a number of reasons I’ll get into below, a new study from Nature Climate Change predicts that the lynx could be extinct by 2060, driven off the planet by anthropogenic climate change.

As its name suggests, the Iberian lynx belongs on the Spanish-Portuguese peninsula, where it exists in a few isolated places in southwestern Spain and perhaps Portugal (though no one really knows). The IUCN estimates the lynx population at a mere 84 to 143 adult cats; recent counts suggest there may be as many as 250 of these kitties. Even the high number is a pretty small population — thus, the classification as Critically Endangered.

The lynx’s habitat has shrunk from 15,700 square miles in the 1950s to just 460 square miles, estimated in 2005. Like its North American counterpart, the Iberian lynx depends on rabbit for sustenance, but the cats’ bunny meal, the European rabbit, has gone through a major decline because of disease, hunting, and habitat loss. The lynx have also suffered from people trapping and poaching them, and hitting them with cars. (Generally cars and wild cats do not mix well.)

The good news for the lynx is that they have a lot of fans and conservation efforts have been well funded. There have been captive breeding programs, work towards restoring their bunny prey, and other efforts to make the world more friendly to the Iberian lynx, all in the hope that the cat population can grow larger, or at least not die out.

The problem, say researchers in the new study, is that none of these plans account for climate change. When they created a computer model of the lynx and rabbit populations that included the expected alterations to temperature and precipitation, they discovered that the lynx would die out within the next 50 years.

“Our models show that the anticipated climate change will lead to a rapid and dramatic decline of the Iberian lynx and probably eradicate the species within 50 years, in spite of the present-day conservation efforts. The only two populations currently present will not be able to spread out or adapt to the changes in time,” coauthor Miguel Araújo, an ecologist at the University of Copenhagen, said in a statement.

All hope is not lost yet, though. If policymakers incorporate climate change into their plans for the lynx, the cats can survive, the scientists say. If climate change were considered in the planning of reintroduction efforts, those efforts could result in there being as many as 900 Iberian lynx by 2090.

The establishment of wildlife corridors along climate pathways might also help. The research team cautions, however, that the immediate nature of the threat, high costs of the corridor creation, and the fact that translocating lynx is technically feasible means that it’s probably easier to just move the cats rather than try to get them to move on their own through a corridor.

“The risk of extinction faced by Iberian lynx within the next 50 years is high,” the researchers write. But with good planning, extinction of the lynx might still be avoided.

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Images Credit: Hector Garrido, CSIC Andalusia Audiovisual Bank, via EurekAlert

July 21, 2013Permalink Leave a comment

It Took Almost 25 Years, But They Finally Identified (A) Waldo

waldoWhere’s Waldo? The more relevant question here is, what’s a Waldo? Waldo is a genus name, belonging to a group of bivalves that have been found in various spots around the world. Now two scientists working on the Pacific Coast of North America have found a new species — Waldo arthuri — though it took nearly 25 years to figure it all out. The scientists report their findings in Zookeys.

Back in 1989, two scientists found a peculiar tiny mollusk, a type of clam, in locations 1,000 miles apart, off the coasts of Santa Barbara, California and Vancouver Island in Canada. The researchers had met up at a scientific conference and talked clams over one of the breaks, quickly realizing they had each found the same thing. But they couldn’t figure out exactly what they had found.

The bivalves were tiny, only a few millimeters in length, with thin, translucent shells and long tentacles. One of the researchers, Diarmaid Ó Foighil of the University of Michigan’s Museum of Zoology, was able to collect some live specimens. “We were looking closely at sea urchins and noticed something crawling on the fine spines covering the urchin body,” Ó Foighil said in a statement. “We were amazed to see that there were minute clams crawling all over the sea urchin.” (In the image above, the clam can be seen among sea urchin spines.)

Why it took a couple decades to determine that the mollusk was a new species isn’t completely described in the paper, but it seems that W. arthuri looks a lot like other members of its genus. Eventually the researchers turned to DNA sequencing — using the help of another scientist who’s a specialist in clam DNA — to tease out the differences in the bivalves. W. arthuri is indeed a species separate from its closest relative, which lives all the way in the south Atlantic off the coast of Argentina.

The researchers write that finding sister taxa in separate ocean basins isn’t an uncommon phenomenon, but it’s a little odd in this case because all the other known Waldo species live far away in high-latitude southern oceans.

The true range of W. arthuri may be even larger than the stretch from California to Canada. The sea urchin Brisaster latifrons, on which the clam lives, can be found from the Galapagos Islands to the Bering Sea, off the coast of Alaska. It’s possible, the scientists say, that the new Waldo can be found all along that area as well.

Image by Diarmaid O’Foighil, via EurekAlert

July 18, 2013Permalink Leave a comment

More Than Just Seagulls Munch On The Seashore

journal.pone.0068221.g005Walk along pretty much any beach and at the high tide mark will be a line of debris. There may be seaweed or shells, bits of driftwood or plastic debris. You probably won’t see any fish, though. And that’s a little odd, because fish do die, and their bodies have to go somewhere. Surely some would wash ashore.

A group of researchers in Australia think that they’ve figured out where the fish go – the fish quickly get scavenged by the critters that live along the shore. But there’s more than just seagulls finding their meals here, the team reports in PLOS One.

The scientists set up a series of experimental plots along a sandy beach on North Stradbroke Island on the east coast of Australia. They picked a spot far from humans, where dogs and beachgoers would be scarce. Then they set out 20 plots, three meters by 10 meters each, and for eight days added about five kilograms of flathead mullet fish to half the plots about two hours before sunset.

The beach was nearly picked clean. Over the eight days, 720 fish were set out and 97 percent were completely eaten. Gulls (silver gulls in this case) ate some of the mullet, but there were several other birds species as well: Torresian crows, whistling kites (b in image above), brahminy kites (a), and white-bellied sea eagles (c and d)

These avian scavengers scoured the beach most often at sunrise and in the first few hours of morning. On three occasions at night, however, red foxes (f) visited the plots, snapping up the easy meal. And on one day, a lace monitor (e) – a large, carnivorous lizard – was spotted on the beach snacking away. That was a surprise because there have been few reports of terrestrial reptiles scavenging on a beach.

One invertebrate also got in on the action. The researchers measured the diameter of ghost crab burrows and, using burrow size as a proxy for crab size, discovered that when they added fish to the experimental plots, bigger ghost crabs moved in to take advantage of the free food.

But birds were the dominant consumers of the carrion fish. And they probably play an important role in this seashore ecosystem, the researchers say, helping to transfer nutrients from the sea onto land and providing a vital link between water and soil.

Image used under Creative Commons license, Schlacher TA, Strydom S, Connolly RM, Schoeman D (2013) Donor-Control of Scavenging Food Webs at the Land-Ocean Interface. PLoS ONE 8(6): e68221. doi:10.1371/journal.pone.0068221

July 17, 2013Permalink Leave a comment

How Silky Sharks Lose Out In Our Quest For Tuna

silkysharkSharks are pretty amazing creatures, as I pointed out yesterday. But since humans tend not to respect these animals — whether out of fear or other feelings — we kill a lot of them. Just take a look at the infographic below. The image, though, which has been making the rounds on the internet lately, might be off, at least a little. That’s because a team led by the Institut de recherche pour le développement in France just estimated the number of silky sharks (above) killed by fish aggregating devices set to catch tuna, and the numbers are shocking. Their study appears in Frontiers in Ecology and the Environment.

Fish aggregating devices (FADs) are huge structures of bamboo and netting that are set adrift in the open water. Tuna have a natural tendency to aggregate among floating objects, so fishermen can use satellite tracking to monitor the devices and just motor up to them and catch a whole bunch of fish.

But a lot of other critters can get tangled up in FADs, including sea turtles, marine mammals and silky sharks, a pelagic species that got its name from its silky smooth skin. In the new study, the researchers tagged and tracked 29 silky sharks off of the Seychelles and in the northern part of the Mozambique Channel. Over the next 94 days, four of the sharks became entangled in FADs.

Extrapolating from their tagged sharks, and assuming that there are some 3,750 to 7,500 active FADs in the Indian Ocean, the researchers calculate that 480,000 to 960,000 silky sharks are killed by the devices in the Indian Ocean each year, and perhaps as many as 2 million worldwide.

“FADs have been used with increasing frequency worldwide for the past 20 to 30 years,” the researchers write, “but it is only now that the unexpected impact on silky sharks in the Indian Ocean has been detected.”

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Top image courtesy of flickr user Syn

July 11, 2013Permalink Leave a comment

Shark’s Tail Is A Deadly Weapon (If You’re A Sardine)

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As if sharks weren’t scary enough, now there’s definitive proof that pelagic thresher sharks (Alopias pelagicus, above) can hunt with their tails, not just their teeth. Even worse, they’ve got two ways of thrashing their tail around, so you’d never know from where death was coming.

But don’t worry. These shark tails are only dangers to sardines.

There had been rumors for years that pelagic threshers could kill small fish with their tails (even the flickr page of the image above mentions it). So a team from the Thresher Shark Research and Conservation Project in the Philippines and Bangor University in Wales set out, armed with underwater video cameras and SCUBA gear, to get the action on film and find out how the sharks accomplished their kills. The results of their study appear in PLOS One.

The researchers dove into the waters off the small coral island of Pescador in the Phillippines many times from June to October 2010, eventually capturing 25 shark hunting events, 22 in which the shark swung its tail overhead and three sideways.

Here’s how an overhead strike works: A shark lunges toward a school of sardines then draws its pectoral fins down, which changes the shark’s pitch and stalls its movement forward. The tail whips overhead, all the way to the shark’s snout, striking at the sardines. Finally, the shark turns a full 180 degrees and chomps up the stunned fish. All this happens in just a few seconds, and the shark’s tail reaches speeds as fast as 48 miles per hour.

The sideways tail-slap takes a little longer, but it’s more of a follow-up weapon. The sharks observed carrying out this move had already completed a successful overhead strike.

The tail-slap worked about a third of the time, but it had the added advantage of being able to catch a shark more than one fish in just one move. That’s a definite advantage; the researchers note that carnivorous ocean-dwelling sharks usually only pursue one piece of prey at a time (perhaps this should make swimmers feel slightly safer after a shark has gone after one of their fellow beachgoers).

Bigger sharks are faster tail-slappers, the scientists found. That’s likely because their longer tails make better whips.

Image courtesy of flickr user Rafn Ingi Finnsson

July 10, 2013Permalink Leave a comment

Rare Lemur Spots Danger By Listening To Other Species’ Alarms

394px-Lepilemur_sahamalazensis_bYou’ve probably never heard of the Sahamalaza sportive lemur (Lepilemur sahamalazensis). The Madagascan species was only discovered in 2006, living in a tiny area on the northwest coast of the island off Africa. Though the lemur’s home recently received protection, the animals are threatened by agriculture and charcoal production. And their rareness prompted the IUCN to move the sportive lemur into the Critically Endangered category just this month.

Unlike some other more familiar lemur species, like the ring-tailed lemurs often seen in zoos, Sahamalaza sportive lemurs are solitary critters that are active at night. During the day, they rest outside tree holes or among tree tangles. It lets them soak up the sun, but staying out in the open also makes them vulnerable to predators, such as the Madagascar harrier hawk, a cat-like carnivore called a fossa, and — perhaps — the Madagascar tree boa. Plus, there are human poachers to worry about.

How do the lemurs manage to keep an eye out for all these threats? They listen to other species that are on the lookout for them, say researchers led by the Bristol Conservation and Science Foundation in the UK. They report their findings in PLOS One.

The scientists traveled to the Ankarafa Forest in the UNESCO Biosphere Reserve and National Park on the Sahamalaza Peninsula in Madagascar to study the lemurs in their home territory. The researchers found 19 Sahamalaza sportive lemurs and, between September and November 2011, played the primates recordings of the vocalizations of other species and watched how the lemurs reacted. Those calls were from two birds, the Madagascar magpie-robin and the crested coua, and another lemur, the blue-eyed black lemur. The researchers played alarm calls that warn of predators as well as sounds the birds and lemurs make when coming into contact with each other, called contact calls.

When the sportive lemurs heard the playbacks of alarm calls that warn of an aerial threat, they became more vigilant and began looking up into the sky. But when they heard terrestrial alarm calls or contact calls, the lemurs didn’t react. (The researchers aren’t sure if the Sahamalaza sportive lemur’s non-reaction to the terrestrial alarm calls mean that they don’t recognize them as a sign of danger or that they decided that it’s just not worth their time.)

“Our results indicate that the Sahamalaza sportive lemur is capable of gleaning information on predator presence and predator type from the referential signals of different surrounding species,” lead author Melanie Seiler, of the Bristol Zoo and the University of Bristol, said in a statement. “Examples for cross-species semantics in lemurs are rare, and this is the first record of lemurs using information across vertebrate classes.”

This ability to listen in on other species is especially important for a solitary creature like the Sahamalaza sportive lemur, the scientists say, because these animals can’t rely on a group of buddies like the ring-tailed lemur can. If they want to avoid predators, eavesdropping can give this sportive lemur a heads up on some of the dangers they face.

Image courtesy of R. Hilgartner, via wikimedia commons

July 8, 2013Permalink Leave a comment