Now this raven-sized early bird has had its brain examined. Amy Balanoff and her colleagues from the American Museum of Natural History recently took CT scans of more than two dozen specimens, including modern birds, Archaeopteryx, and closely related non-avian dinosaurs such as tyrannosaurs, to size up the different species’ brain power.

“Bird-brained” is actually a misnomer. (Crows demonstrate this again and again.) Modern birds are distinguished from reptiles by their brains, which are enlarged compared to body size. This “hyperinflation,” most obvious in the forebrain, is important for providing the superior vision and coordination required to fly.

By stitching together the CT scans, the scientists created 3D reconstructions of the skulls’ interiors. In addition to calculating the total volume of each digital brain cast, the research team also determined the size of each brain’s major anatomical regions, including the olfactory bulbs, cerebrum, optic lobes, cerebellum, and brain stem.

The researchers found that in terms of volumetric measurements, Archaeopteryx is not in a unique transitional position between non-avian dinosaurs and modern birds. Several other non-avian dinosaurs sampled, including bird-like oviraptorosaurs and troodontids, actually had larger brains relative to body size than Archaeopteryx.

“If Archaeopteryx had a flight-ready brain, which is almost certainly the case given its morphology, then so did at least some other non-avian dinosaurs,” Balanoff says.

“Archaeopteryx has always been set up as a uniquely transitional species between feathered dinosaurs and modern birds, a halfway point,” she says. “But by studying the cranial volume of closely related dinosaurs, we learned that Archaeopteryx might not have been so special.”

If not unique, where should we place Archaeopteryx in the tree of life? More research is needed. The current study is published this week in Nature.

Image: Amy Balanoff, American Museum of Natural History

Shocking news? Perhaps… When capturing insects in their webs, spiders get a little help from electricity, according to a new study by UC Berkeley scientists.

Postdoc Victor Manuel Ortega-Jimenez, working in Berkeley’s Animal Flight Laboratory, usually studies hummingbird flight, but became interested in how spider webs attract insects while playing with his four year-old daughter. “I was playing with my daughter’s magic wand, a toy that produces an electrostatic charge, and I noticed that the positive charge attracted spider webs,” he says. “I then realized that if an insect is positively charged too, it could perhaps attract an oppositely charged spider web to affect the capture success of the spider web.”

As mentioned in our “Bee Positive” video, as insects fly through the air, they naturally become positively charged. Spider webs, on the other hand, are normally negatively or neutrally charged.

To test his spider web hypothesis, Ortega-Jimenez found cross-spider (Araneus diadematus) webs along streams in Berkeley and brought them into the lab. He then used an electrostatic generator to charge up dead insects—aphids, fruit flies, green-bottle flies and honeybees—and drop them into a neutral, grounded web.

“Using a high-speed camera, you can clearly see the spider web is deforming and touching the insect before it reaches the web,” he says. Insects without a charge did not do this. (Video is available here.)

Ortega-Jimenez also suspects that light, flexible spider silk, the kind used for making the spirals built on top of the stiffer silk that forms the spokes of a web, may have developed because it more easily deforms in the wind and the presence of electrostatic charges to aid prey capture.

“Electrostatic charges are everywhere, and we propose that this may have driven the evolution of specialized webs,” he says.

The findings were published last week in Scientific Reports.

Photo by Victor Manuel Ortega-Jimenez, UC Berkeley

In life, you must make choices. You can’t succeed at everything. For example, Tiger Woods is an excellent golfer, but a terrible husband. Shaquille O’Neal? Great at basketball, but acting? Not so much. (Bo Jackson could be the exception.)

Penguins realized this about 70 million years ago, when they gave up flying for diving and swimming. Now, a study in the Proceedings of the National Academy of Sciences explains why.

Researchers from the University of Manitoba studied murres, a type of auk—a family of birds that is similar to penguins but not at all related. Apparently, this species didn’t get the message about excelling at one skill. The murres both fly and swim. But research shows the dual skills come at a very high cost.

The scientists measured the energy usage of the birds. According to National Geographic News Watch,

They injected the birds with stable isotopes of oxygen and hydrogen to serve as tracers to mark the physical costs of their activities.

The team found that when flying, the murres’ sustained the highest metabolic rates ever measured for any animal. (Previously, the bar-headed goose held the record, but they are the world’s high-altitude flying champions.) In fact, the energy costs of the murres were 33% higher than the biologists expected after doing biomechanical modeling of the bird. The birds are sufficient swimmers, but researchers found that the birds’ energy costs while swimming were higher than penguins, who are specialists in the sea.

Lead-author Kyle Elliott remarks in both Nature News and ScienceNOW that the murres are at “the edge of what a bird can do.” And the team suggests that such high flight costs may have led aquatic birds, like penguins, to develop their wings for  propelled diving in response to foraging opportunities at increasing depths, behavioral adaptations that led, finally, to flightlessness.

In short, good flippers don’t fly well. But they’re great for swimming and diving. Fine choice, penguins.

Image: Ken FUNAKOSHI/Flickr

Not only are they the only mammals that can fly, but bats also show off with their immunity to viruses and other diseases. What gives?

Well, according to a recent study in Science, these two abilities—flight and immunity—might be related in the winged animals.

A group of international researchers sequenced the entire genomes of two species of bats—the fruit bat Pteropus alecto and the insectivore Myotis davidii. These two species are from the two distinct sub-orders of bats—P. alecto is a megabat and M. davidii, a microbat. By comparing and contrasting the two species’ genomes and those of other mammals (human, rhesus macaque, mouse, rat, dog, cat, cow, and horse), the scientists could refine bats’ place in the tree of life as well as determine the evolution of some of their bat-traits.

Study co-author Chris Cowled, of the Australian Animal Health Laboratory, describes how remarkable these traits are. “Bats are a natural reservoir for several lethal viruses, such as Ebola and SARS, but they often don’t succumb to disease from these viruses. They also live a long time compared to animals similar in size.”

It turns out the trick for this trait is flight. Flying is a very energy intensive activity that also produces toxic by-products, and bats have developed some novel genes to deal with the toxins. Some of these genes are implicated in the development of cancer or the detection and repair of damaged DNA.

“What we found intriguing was that some of these genes also have secondary roles in the immune system,” says Cowled. “We’re proposing that the evolution of flight led to a sort of spill over effect, influencing not only the immune system, but also things like aging and cancer.

“A deeper understanding of these evolutionary adaptations in bats may lead to better treatments for human diseases, and may eventually enable us to predict or perhaps even prevent outbreaks of emerging bat viruses,” says Cowled.

Sounds bat-tastic.

Image: James Niland/Wikipedia

But here’s an interesting twist to the tale. A recently designed robot at the Biomimetic Millisystems Lab at UC Berkeley is now shedding light on flight evolution.

A research team, led by Ron Fearing—we highlighted some of his early biomimicry work a few years ago here—wanted their robotic cockroach, DASH, to move faster. DASH is a lightweight, speedy robot made of inexpensive, off-the-shelf materials first launched in 2009. Its small size makes it a candidate for deployment in areas too cramped or dangerous for humans to enter, such as collapsed buildings.

But compared with its biological inspiration, the cockroach, DASH had certain limitations as to where it could scamper. Remaining stable while going over obstacles is fairly tricky for small robots, so the researchers affixed DASH with lateral and tail wings borrowed from a store-bought toy to see if that would help.

The researchers ran tests on four different configurations of the robotic roach, now called DASH+Wings. The test robots included one with a tail only and another that just had the wing’s frames, to determine how the wings impacted locomotion.

With its motorized flapping wings, DASH+Wings’ running speed nearly doubled, going from from 0.68 meters per second with legs alone to 1.29 meters per second. The robot could also take on steeper hills, going from an incline angle of 5.6 degrees to 16.9 degrees.

“With wings, we saw improvements in performance almost immediately,” says Kevin Peterson, a Ph.D. student in Fearing’s lab. “Not only did the wings make the robot faster and better at steeper inclines, it could now keep itself upright when descending.

The engineering team’s work caught the attention of animal flight expert Robert Dudley, a UC Berkeley professor of integrative biology, who noted that the most dominant theories on flight evolution have been primarily derived from scant fossil records and theoretical modeling.

He referenced previous computer models suggesting that ground-dwellers, given the right conditions, would need only to triple their running speed in order to build up enough thrust for takeoff. The fact that DASH+Wings could maximally muster a doubling of its running speed suggests that wings do not provide enough of a boost to launch an animal from the ground. This finding is consistent with the theory that flight arose from animals that glided downwards from some height.

“The fossil evidence we do have suggests that the precursors to early birds had long feathers on all four limbs, and a long tail similarly endowed with a lot of feathers, which would mechanically be more beneficial for tree-dwelling gliders than for runners on the ground,” says Dudley.

Dudley said that the winged version of DASH is not a perfect model for proto-birds – it has six legs instead of two, and its wings use a sheet of plastic rather than feathers – and thus cannot provide a slam-dunk answer to the question of how flight evolved.

“It’s still notable that adding wings to DASH resulted in marked improvements in its ability to get around,” Fearing adds. “It shows that flapping wings may provide some advantages evolutionarily, even if it doesn’t enable flight.”

Their research was published online today in the journal Bioinspiration and Biomimetics.

Image by Kevin Peterson, Biomimetic Millisystems Lab