Male koalas have hefty mating call
Based on their size, male koalas should have a mating call that sounds like a human baby’s cry. But the call is actually closer in pitch to an elephant’s rumble.
That is because koalas have a special sound-producing organ not previously seen in any land-dwelling mammal, researchers say.
“In the larynx the vocal cords were normal, but outside there were these fleshy lips,” said David Reby, a researcher at the University of Sussex in England who was involved with the study, described in the journal Current Biology.
The fleshy lips are found in the koala’s soft palate, at the junction of the oral and nasal cavities.
Reby’s colleague Benjamin Charlton, the study’s lead author, inserted a pump and an endoscopic camera into the trachea of a euthanized koala in Australia to observe how the vocal folds vibrated and produced sound.
“When the koalas inhale they tense these lips, and it allows them to exaggerate their size through sound,” Reby said.
As a rule, an animal’s size reflects the dimensions of its vocal folds, which limit the lowest frequency an animal can reach. Smaller species tend to have calls with a higher frequency.
“The message here is that when there is a need to communicate something, evolution can lead to the emergence of new organs,” Reby said.
An inexpensive way to print metal parts
Low-cost 3-D plastic printers can produce almost anything, from clothes and toys to household items and furniture.
Now, researchers from Michigan Technological University say they have developed an affordable 3-D metal printer.
For years, large companies have used metal printers to make items like automobile parts and titanium body implants, said Joshua Pearce, a materials scientist at Michigan Tech who led the research and wrote about it in the journal IEEE Access.
“Those printers are awesome, but they start at a half a million dollars and go up,” he said.
The researchers’ 3-D metal printer cost less than $1,500. They used open-source software and off-the-shelf components, including a microcontroller and a small welding machine, and made a sprocket with it.
Pearce cautioned that the printer was more dangerous to use than a 3-D plastic printer, requiring more safety gear. Still, he said, the technology would give small companies an inexpensive, rapid way to build prototypes. Scientists could use the printer to build tools for research. And developing countries could use it to print repair parts for machines like windmills.
– New York Times