BS Thurner Hof via Wikimedia Commons // CC BY-SA 3.0
BS Thurner Hof via Wikimedia Commons // CC BY-SA 3.0

Noise Keeps Animals From Recognizing the Scent of Danger

BS Thurner Hof via Wikimedia Commons // CC BY-SA 3.0
BS Thurner Hof via Wikimedia Commons // CC BY-SA 3.0

Picture this: you’re driving somewhere you’ve never been before, blasting your favorite tunes. As you approach your destination and start checking house numbers, your hand reaches for the dial and turns the radio down. Without even realizing it, you’ve decided to redirect your attention from sounds to sights. Now imagine that your passenger has interfered. They’ve turned the radio all the way up and opened all the windows, filling the car with the roar of traffic and wind as you’re trying to focus. Harder now, isn’t it? And it isn’t just us; scientists say mongooses exposed to traffic noise overlook crucial clues from their other senses—clues that could mean the difference between life and death. Their findings were published today in the journal Current Biology.

We’ve known for a long time that pollution and urbanization are bad news for everyone. Much of our research has focused on the physical effects like smog, water contamination, and habitat destruction. We haven’t paid too much attention to the toxic effects of too much noise until recently, but what we’ve learned is troubling.

Studies have shown that exposure to anthropogenic, or human-made, noise causes intense stress for animals, can interfere with their communication, and may even keep them from migrating and having sex. All of these issues could mess with a species’ chances of survival in the long run.

The short-term effects have been less understood, says biologist Amy Morris-Drake of the University of Bristol. She and her colleagues decided to test the immediate consequences of noise on one species, the dwarf mongoose (Helogale parvula), whose South African habitat is increasingly bounded by cities and roads.

The dwarf mongoose has many predators, including jackals, hyenas, civets, servals, honey badgers, wildcats, bigger mongooses, and an assortment of reptiles. The key to survival, consequently, is constant olfactory vigilance: sniffing the air for the scent of predator poop.

The research team headed into mongoose territory with audio recordings of traffic noise and Ziploc baggies of poop from servals, wildcats, and giraffes. (Because giraffes present no threat to mongooses, their poop was used as a control group.) The researchers set out the poop and played their road sounds, watching the mongooses to see how they would respond.

The results were not encouraging. Exposure to traffic noises significantly decreased the mongooses’ vigilance. They spent less time investigating the predator poop; they were less likely to scan the area for potential threats; and they were less likely to retreat to the entrance of their burrow to prepare for an attack. If the scientist-provided poop, and therefore the threat, had been real, those mongooses would have found themselves in significant danger.

"Our study suggests that noise pollution can have a negative effect in terms of information use,” said co-author Andy Radford. “Given the demonstrated effects, considering the interactions among multiple sensory channels is critically important if we are to understand fully the consequences of human-induced environmental change."
 
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These Sparrows Have Been Singing the Same Songs for 1500 Years
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iStock

Swamp sparrows are creatures of habit—so much so that they’ve been chirping out the same few tunes for more than 1500 years, Science magazine reports.

These findings, published in the journal Nature Communications, resulted from an analysis of the songs of 615 adult male swamp sparrows found in six different areas of the northeastern U.S. Researchers learned that young swamp sparrows pick up these songs from the adults around them and are able to mimic the notes with astounding accuracy.

Here’s what one of their songs sounds like:

“We were able to show that swamp sparrows very rarely make mistakes when they learn their songs, and they don't just learn songs at random; they pick up commoner songs rather than rarer songs,” Robert Lachlan, a biologist at London’s Queen Mary University and the study’s lead author, tells National Geographic.

Put differently, the birds don’t mimic every song their elders crank out. Instead, they memorize the ones they hear most often, and scientists say this form of “conformist bias” was previously thought to be a uniquely human behavior.

Using acoustic analysis software, researchers broke down each individual note of the sparrows’ songs—160 different syllables in total—and discovered that only 2 percent of sparrows deviated from the norm. They then used a statistical method to determine how the songs would have evolved over time. With recordings from 2009 and the 1970s, they were able to estimate that the oldest swamp sparrow songs date back 1537 years on average.

The swamp sparrow’s dedication to accuracy sets the species apart from other songbirds, according to researchers. “Among songbirds, it is clear that some species of birds learn precisely, such as swamp sparrows, while others rarely learn all parts of a demonstrator’s song precisely,” they write.

According to the Audubon Guide to North American Birds, swamp sparrows are similar to other sparrows, like the Lincoln’s sparrow, song sparrow, and chipping sparrow. They’re frequently found in marshes throughout the Northeast and Midwest, as well as much of Canada. They’re known for their piercing call notes and may respond to birders who make loud squeaking sounds in their habitat.

[h/t Science magazine]

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ZUMA Press, Inc., Alamy
5 Fascinating Facts About Koko the Gorilla
ZUMA Press, Inc., Alamy
ZUMA Press, Inc., Alamy

After 46 years of learning, making new friends, and challenging ideas about language, Koko the gorilla died in her sleep at her home at the Gorilla Foundation in Woodside, California on June 21, 2018. Koko first gained recognition in the late 1970s for her ability to use sign language, but it was her friendly personality that made her a beloved icon. Here are five facts you should know about the history-making ape.

1. SHE KNEW OVER 1000 SIGNS.

Francine "Penny" Patterson, then a graduate student at Stanford University, was looking for an animal subject for her inter-species animal communication experiment in the early 1970s when she found a baby gorilla at the San Francisco Zoo. Originally named Hanabiko (Japanese for "fireworks child," a reference to her Fourth of July birthdate), Koko took to signing quickly. Some of the first words Koko learned in "Gorilla Sign Language," Patterson's modified version of American Sign Language, were "food," "drink," and "more." She followed a similar trajectory as a human toddler, learning the bulk of her words between ages 2.5 and 4.5. Eventually Koko would come to know over 1000 signs and understand about 2000 words spoken to her in English. Though she never got a grasp on grammar or syntax, she was able to express complex ideas, like sadness when watching a sad movie and her desire to have a baby.

2. SHE CHANGED WHAT WE KNEW ABOUT LANGUAGE.

Not only did Koko use language to communicate—she also used it in a way that was once only thought possible in humans. Her caretakers have reported her signing about objects that weren't in the room, recalling memories, and even commenting on language itself. Her vocabulary was on par with that of a 3-year-old child.

3. SHE WASN'T THE ONLY APE WHO SIGNED.

Koko was the most famous great ape who knew sign language, but she wasn't alone. Michael, a male gorilla who lived with Koko at the Gorilla Foundation from 1976 until his death in 2000, learned over 500 signs with help from Koko and Patterson. He was even able to express the memory of his mother being killed by poachers when he was a baby. Other non-human primates have also shown they're capable of learning sign language, like Washoe the chimpanzee and Chantek the orangutan.

4. SHE HAD FAMOUS FRIENDS.

Koko received many visitors during her lifetime, including some celebrities. When Robin Williams came to her home in Woodside, California in 2001, the two bonded right away, with Williams tickling the gorilla and Koko trying on his glasses. But perhaps her most famous celebrity encounter came when Mr. Rogers paid her a visit in 1999. She immediately recognized him as the star of one of her favorite shows, Mister Rogers' Neighborhood, and greeted him by helping him take off his shoes like he did at the start of every episode.

5. SHE WAS A LOVING CAT MOM.

Koko was never able to have offspring of her own, but she did adopt several cats. After asking for a kitten, she was allowed to pick one from a litter for her birthday in 1985. She named the gray-and-white cat "All Ball" and handled it gently as if it were her real baby, even trying to nurse it. She had recently received two new kittens for her 44th birthday named Ms. Gray and Ms. Black.

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