Earthweek: a diary of the planet

Cats vs. rats

The first study to look at how talented feral cats are at killing wild rats found that the felines just aren’t very good at that task.

Writing in the journal Frontiers in Ecology and Evolution, lead researcher Michael H. Parsons of Fordham University in New York said the findings add to the growing evidence that any benefit of using cats to control city rats is outweighed by the threat they pose to birds and other urban wildlife.

Earlier studies found that cats prefer smaller, defenseless prey such as birds and smaller native wildlife, which makes cats a threat to urban ecosystems.

Earthquakes

More than 1,400 people have been confirmed dead — and that number is expected to climb perhaps to 2,000 — on the Indonesian island of Sulawesi where a magnitude 7.5 earthquake caused violent ground motion and a subsequent tsunami devastated the city of Palu. Earth movements also were felt

on the Indonesian island of Flores and in interior parts of Southern California.

Eruptions

Mount Soputan spewed ash over Indonesia’s Sulawesi Island following the disastrous magnitude 7.5 quake that struck there. Also this week, Mexico City was dusted by volcanic ash after the Popocatepetl volcano produced 183 emissions of ash and vapor during a 24-hour period.

Tropical cyclones

Powerful Typhoon Trami killed four people and injured more than 120 others as it

raked the heart of Japan. Typhoon Kong-Rey approached southern Japan and South Korea at the end of the week. If it makes landfall in Japan, it would be the ninth tropical storm to hit the island nation this year.

Also this week, Hurricanes Walaka and Sergio churned the eastern Pacific, while remnants of Hurricane Rosa unleashed flooding in Mexico and the U.S. Southwest. Meanwhile, Hurricane Leslie formed in the Atlantic.

Canine smarts

Dog lovers around the world might be disappointed to hear that researchers have found that man’s best friend probably is not as smart as they think.

“Dogs are special, but they’re not exceptional,” says Britta Osthaus of Canterbury Christ Church University in England. “They’re smart, but they’re not stand-out smart.”

She and fellow researcher Stephen Lea compared the brain power of dogs with wolves, bears, lions and hyenas, and found that the abilities of canines were at least matched by several species in each group. “We are doing dogs no favor by expecting too much of them,” said Osthaus.

Bovine gas control

The burps and flatulence of cows contribute to about 4 percent of all greenhouse gas created worldwide, but a Swiss company is touting a way to reduce those bovine emissions.

Kurt Schaller, co-founder of Agolin, told Reuters that his company’s special feed can cut those gases by about 10 percent per cow. Schaller told the agency that trials have shown its product also helps increase milk yield and feed efficiency. The company says this is achieved by using additives based on botanical compounds.

Summer melt

The Arctic’s sea ice melted to its sixthlowest coverage on record in late September. The annual minimum of 1.77 million square miles measured on Sept. 19 and 23 followed the second-lowestever wintertime expanse seen earlier this year.

“This year’s minimum is relatively high compared to the record low extent we saw in 2012, but it is still low compared to what it used to be in the 1970s, 1980s and even the 1990s,” said Claire Parkinson, a climate change senior scientist at NASA’s Goddard Space Flight Center in Maryland.