July 30, 2009
It turns out there’s more to a toucan’s bill than pretty colors and a penchant for Fruit Loops.
Originally described as “grossly monstrous” by the Comte de Buffon, the toucan’s beak was theorized by Charles Darwin to be related to sexual selection. The toucans with the biggest bills were thought to have the most success attracting a mate and reproducing, the same explanation used for the extravagant plumes on peacocks.
However, scientists now have evidence that the long beak of a toucan regulates heat distribution, acting as a thermal radiator of sorts. Glenn J. Tattersall of Brock University and Denis V. Andrade and Augusto S. Abe of Sao Paulo State University studied the toco toucan (Ramphastos toco), the largest member of the toucan family that also has the largest bill relative to body size of any bird.
Using infrared thermography and thermal imaging cameras, the team monitored the toucans’ response in a temperature-controlled chamber. Below a temperature of about 60 degrees Fahrenheit, the beak was somewhat colder than ambient temperature, meaning that the blood vessels between the bony core of the bill and its hornlike covering were constricted.
Conversely, as temperatures increased above 70 degrees, blood flow increased, making the bill warmer and helping the bird cope with the extra heat load.
In a recent paper published in Science researchers note:
Our results indicate that the toucan’s bills is, relative to its size, one of the largest thermal windows in the animal kingdom, rivaling elephants’ ears in its ability to radiate body heat … Given the rapid radiation of bill structures and diversity of beak morphologies of birds, thermal constraints from bill heat loss may prove to be a common feature among many avian fauna.
July 18, 2009
On July 16, 1969, NASA launched Apollo 11, the mission that put two men on the moon four days after lift-off.
Forty years later, historians and NASA officials are still trying to gauge the legacy of the Apollo program. On Thursday, five panelists met at NASA headquarters to discuss its impact.
Many of their conclusions were expected: Apollo was one of, if not the, greatest achievement of the 20th century, a claim that all five participants repeated throughout the hour. Humans will remember this moment not only for arriving at the moon, but also for leaving this planet. Photos from Apollo of Earth showed a fragile orb surrounded by the darkness of space and gave a boost to the environmental movement, said Roger Launius, curator at the National Air and Space Museum, as he noted Earth Day was first celebrated in 1970.
Craig Nelson, author of Rocket Men: The Epic Story of the first Men on the Moon, observed that before Apollo, space travel was science fiction—and now it’s a form of transportation. The geopolitical context of the Cold War was the driving force behind the Apollo mission and President Kennedy’s support of the program, as John Logsdon of the Air and Space Museum reminded us.
But there were some unexpected critiques of the program, too. Apollo had one goal, which was to reach the moon before the Soviets. President Kennedy gave a timetable of accomplishing that goal by the end of the 1960s. While this was good for mobilizing public support, it created a precedent that makes it hard for multi-goal programs today, like Constellation, to gather similar support (Constellation has eight main goals and a 20-year timeline for achieving them). This was something that all of the panelists agreed with, including Cristina Guidi, director of Constellation’s exploration systems mission directorate.
In addition to scholarly discourse, the Apollo anniversary is an opportunity for celebration and inspiration. You can follow the action on Twitter, watch archival footage of the first steps on the moon or chronicle the entire flight of Apollo 11 in realtime.
June 10, 2009
Anyone who has visited a zoo can attest to the human-like qualities of our close relatives. Whether you’re watching chimpanzees, bonobos, orangutans or gorillas, it’s the facial expressions and social interactions that most make them appear similar to humans. Now researchers have evidence of another behavior shared between humans and nonhuman primates: laughter.
A study released last Thursday in Current Biology suggests that the origins of human laughter can be traced back 10 to 16 million years ago, to the last common ancestor of humans and all the modern great apes.
Marina Davila Ross and her fellow researchers recorded and analyzed the acoustics of “tickle-induced vocalizations” (see video below) in infant and juvenile orangutans, gorillas, chimpanzees, bonobos and humans. The similarities support the idea that laughter is an emotional expression shared among all five species.
According to Davila Ross’ study, the laughter of our last common ancestor probably consisted of long, slow calls in a short series. Human laughter evolved distinctive features, like regular vocal cord vibrations that are more even, as a result of selection from variation present in that last common ancestor.
The study’s findings also add evidence to the theory of continuity between nonhuman primates’ displays and human expressions—something that Charles Darwin posited in his 1872 book, The Expression of the Emotions in Man and Animals. Darwin’s work was popular not only for the text, but also the photographs and sketches that showed the striking similarities among humans, nonhuman primates and other animals as they expressed emotions like helplessness and anger.
Darwin focused on the involuntary signs of emotions in humans and animals in this 1872 work:
We can understand how it is, that as soon as some melancholy state passes through the brain, there occurs a just perceptible drawing down of the corners of the mouth, or a slight raising up of the inner ends of the eyebrows, or both movements combined, and immediately afterwards a slight suffusion of tears … The above actions may be considered as vestiges of the screaming fits, which are so frequent and prolonged during infancy.
While both Darwin and Davila Ross note similarities in emotional expressions, something is still missing. Davila Ross ends her paper about laughter by writing:
The question left unaddressed is of course why those particular acoustic properties emerged, and what functions they may have served as laughter became a pervasive and characteristic component of human social communication.
We know that we’ve been laughing for millions of years, but we’re still not sure why.