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Feral cats can roam over great distances, a new study finds (image courtesy of flickr user 37prime)

Do feral kitties live good lives? The Washington Post asked that question last week in a story that examined the practice of controlling feral cat populations by trapping cats, spaying or neutering them, and then releasing them back into their former home environments (it’s often called Trap-Neuter-Return or TNR).

The Humane Society of the United States, the ASPCA and other supporters say the nation’s estimated 50 million to 150 million feral felines often live healthy lives. They also say TNR has added benefits: After a cat colony is sterilized, nuisance behaviors such as fighting and yowling are reduced, and the feral population stabilizes. Feral cats can keep rats in check, too.

Skeptics, including People for the Ethical Treatment of Animals (PETA) and some veterinarians, argue the life of an alley cat is rarely pleasant. In many cases, they say it’s actually more humane to euthanize cats, rather than condemn them to a harsh life on the streets.

Some insight into the lives of both feral and owned kitties comes from a new study, published in the Journal of Wildlife Management, in which researchers set out to track free-roaming feral and owned cats by placing radio transmitters on 42 kitties in and around Urbana-Champaign, Illinois. Twenty-three of those transmitters also had tilt and vibration sensors that measured activity.

The scientists found that the feral cats had home ranges that stretched across large areas; one male kitty’s range covered 1,351 acres (2.1 square miles). They roamed over a wide variety of habitats, most often in urban areas and grasslands, including a restored prairie. In winter, they preferred urban spots, forests and farmland, all places that would provide greater shelter from bad weather and help them keep warm. Cats that had owners, meanwhile, tended to stick close to home, with their range sizes averaging a mere 4.9 acres.

Feral kitties were also more active than cats that had homes. Unowned cats spent 14 percent of their time in what the scientists classified as “high activity” (running or hunting, for example), compared with only 3 percent for kitties with owners. “The unowned cats have to find food to survive, and their activity is significantly greater than the owned cats throughout the day and through the year, especially in winter,” says study co-author Jeff Horn of the University of Illinois.

In addition, the feral cats’ daily activity patterns—sleeping during the day and being active at night, which likely reflects the behavior of their prey, small mammals, as well as lets them better avoid humans—was very different from kitties with homes. Those animals were most active in the morning and evening, when their owners were likely home and awake.

Only one owned kitty died during the study, compared with six feral cats. Two of the feral cats were killed by coyotes, and the researchers believe that at least some of the others were killed by other cats, as the owned kitty was. Cats that live outdoors, even just part of the time, are at risk of death from other cats as well as diseases such as rabies, feline leukemia and parasites, the researchers note.

And of course there’s the fact that cats, owned and unowned, kill wildlife. “Owned cats may have less impact on other wildlife than unowned cats because of their localized ranging behavior, or conversely, they may have a very high impact withing their smaller home ranges,” the scientists write. “Free-roaming cats do kill wildlife and pose a disease risk; cat owners should keep pets indoors.”

But there’s nothing in this study that convinces me that feral cats are living such harsh lives that death would be better, as PETA and other TNR skeptics have contended. Feral cats do have harder and shorter lives than our pets. They have to find their own food and water and shelter, and this isn’t easy. But that’s what any wild creature has to do, and to imply that their lives are worthless because they are hard is, frankly, ridiculous.

Scientists use satellite images of the kelp canopy (here, as seen from underwater) to track this important ecosystem over time (Credit: Stuart Halewood)

I remember an analogy from one of my marine science classes, that studying the ocean is sometimes like trying to study a forest by dropping a bucket from a helicopter. It explains why we know comparatively little about ocean ecosystems, even when they’re situated close to populous areas of land, like the forests of giant kelp (Macrocystis pyrifera) in the Santa Barbara Channel off California. These kelp ecosystems are important because they provide food and habitat for a variety of fish and other species. And now a group of scientists led by the University of California, Santa Barbara found a new way to study the kelp, which enabled them to look at long-term changes in this ecosystem for the first time. (Their results appear in Marine Ecology Progress Series.)

The scientists were able to use images of the area made by the Landsat 5 satellite from 1984 through 2009. (Scientists were not previously able to use the extensive collection of imagery because of the cost; in 2009, Landsat images were made freely available.) “Giant kelp forms a dense floating canopy at the sea surface that’s distinctive when viewed from above,” the researchers wrote. They used the imagery to document the changes in the kelp forests over time and found that, during most years, the forests go through an annual cycle, rapidly growing in spring and summer and dying back during the winter. In some regions, huge waves limit the kelp’s growth, while in others they are held back by a lack of nutrients.

“We know from scuba observations that individual kelp plants are fast-growing and short-lived,” says study co-author Kyle Cavanaugh of UCSB. “The new data show the patterns of variability that are also present within and among years at much larger spatial scales. Entire kelp forests can be wiped out in days, then recover in a matter of months.”

Kelp biomass off Santa Barbara, 1984-2009, as measured by the Landsat 5 satellite (Credit: NASA; SBC LTER Site)

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Most fatal black bear attacks are carried out by hungry males (photo courtesy of flickr user Arthur Chapman)

Black bears (Ursus americanus) can be found as far south as northern Mexico and well into Canada and Alaska. One study estimated that there were 750,000 to 900,000 black bears distributed across North America, and their numbers have been growing. A recent study in the Journal of Wildlife Management documented 59 fatal black bear attacks, resulting in 63 human deaths, in the United States and Canada from 1900 through 2009. And the scientists learned that many of our assumptions about bear dangers are wrong. The most important finding is that it is lone, hungry males—not mothers with young—who are most often the killers. Some advice from the researchers on avoiding a fatal attack:

1 ) Travel in groups of three or more. Fatal attacks were more common when people traveled singly or in pairs. Larger groups are likely louder, and a bear may find them more intimidating.

2 ) Learn to recognize signs that bears are in the area.

3 ) Keep food and garbage away from bears. Food or garbage was present in 38 percent of the documented fatal black bear attacks, and the scent may have attracted the bears. In addition, the scientists speculate the presence of food may make the bears more aggressive, thus increasing the possibility of an attack.

4 ) Carry bear spray (which has capsaicin, the chemical that makes chili peppers hot) if you’re going to be in bear territory. No one who has been killed by a black bear in the past was carrying bear spray with them. That doesn’t mean that the spray is guaranteed to fight off an attacking bear, but it could help.

5 ) Learn to recognize the behavior of a black bear that is considering you for its next meal. These bears silently stalk their prey, sometimes for hours, before quickly rushing to attack.

6 ) A black bear that is stalking you may be deterred by aggressive actions, such as shouting, spraying it with bear spray or hitting it with rocks, sticks or even fists. Avoid harassing bears that are just going about their business, though; females seldom attack humans except when provoked by people or dogs.

7 ) Be extra careful in August, when hungry bears are filling up with high-energy foods in preparation for winter denning. Fatal attacks most often occur in this month.

8 ) Don’t assume that there’s less danger in Canada and Alaska simply because there are fewer encounters between black bears and humans. A greater proportion of fatal attacks occur in the northern parts of the black bear’s range, perhaps because these bears are less habituated to people or more food-stressed than southern bears.

Fatal attacks are not more likely among any age group or in response to any specific human activity. And this advice does not apply to other species of bears (among brown bears, for example, mama bears with young are responsible for more fatal attacks). But it’s a good reminder for anyone planning to take advantage of North America’s great outdoors this summer to prepare for any predators you might meet along your way.

What bits of the universe are legal to own? (credit: NASA)

If someone tries to sell you the Brooklyn Bridge, you know it’s a hoax. But what about a meteorite, moon or star? Here’s a quick guide to owning anything with origins outside the Earth:

Lunar Property: The 1967 Outer Space Treaty prohibits nations from claiming property rights on the Moon or anywhere else in space (including planets, asteroids, comets and anything else you can think of). Dennis Hope, a Nevada entrepreneur, thinks that the treaty has a loophole, however, and doesn’t prohibit a person—who, after all, is not a nation—from claiming rights to extra-terrestrial objects. And so he claimed the Moon in 1980, later set up the Lunar Embassy, complete with its own government, and started selling. An acre of “prime” lunar property goes for $19.99 (plus $1.51 in tax, $12.50 shipping and handling and an extra $2.50 if you want your name printed on the deed). Good luck trying to claim that land, though.

Lunar Resources: A 1979 treaty set out guidelines for managing the Moon’s natural resources, though hardly anyone signed that agreement. That’s not a problem for now, but it does present an extra layer of uncertainty on any future plans to colonize our nearest neighbor.

Moon Rocks: These might seem to be an obtainable way to own a bit of Earth’s biggest satellite, but you’d be out of luck. NASA owns every bit of the 840 pounds of the stuff that Apollo astronauts brought back to Earth from 1969 to 1972. Scientists can request bits of lunar material to study, but it’s illegal to own or sell any of it. Those who can afford to buy a piece of space history, however, might get a tiny bit of Moon dust if they buy an object used by one of the Apollo astronauts.

Meteorites: In the United States, meteorites belong to whoever owns the property where it lands (although that’s not always straightforward), and then they can be sold or donated wherever the owner likes. Most meteorites originate in the solar system’s Asteroid Belt, but some come from the Moon or Mars, making meteorites the easiest way to own a bit of those faraway places.

Stars: Stars and other astronomical objects have strict naming conventions overseen by the International Astronomical Union (which means that there’s far less fun in these names than in naming critters and plants). That hasn’t stopped any number of companies from selling stars, though. But, as the IAU notes, all you really get is “an expensive piece of paper and a temporary feeling of happiness, like if you take a cup of tea instead of the Doctor’s recommended medicine.”

Scientists have access to other bits of the universe, too, such as a sample of asteroid collected by the Japanese Haybusa mission or pieces of comet brought back by NASA’s Stardust. But for the rest of us, we’ll just have to make do with visiting a museum.

Llamas can still be found at Machu Picchu today (image courtesy of flickr user Santiago S.V.)

The Incas dominated much of South America for centuries, building a vast empire that stretched high into the Andes where the terraced city of Machu Picchu still inspires wonder. Now scientists in France and Peru, reporting in the journal Antiquity, reveal what made it all possible: llama dung.

The researchers analyzed mud cores from the bottom of a lake near the Incan town of Ollantaytambo in Peru. These sediment samples contain a record of past environmental conditions in the area. (In some places, scientists have found cores that give records stretching back tens of thousands of years). In the Peruvian sample, the researchers found a sudden increase in maize (corn) pollen starting around 2,700 years ago. Unlike the wild-grown quinoa that the Incas had previously relied upon to survive, cultivated maize provided more energy and could be stored or transported long distances, perfect for fueling a growing empire. But how were they able to grow maize high up in the mountains?

The mud samples also provide that answer. About the same time that there was an increase in maize pollen, there was an increase in oribatid mites, tiny insects that live in soil and feed on feces. The researchers conclude that dung from llamas—which the Incas had domesticated hundreds of years previously—provided food for all those mites. Llamas “defecate communally so [their dung] is easily gathered,” Alex Chepstow-Lusty of the French Institute of Andean Studies explained to the Guardian. The Incans could then use the poop as fertilizer for their maize fields, which reached elevations up to 11,000 feet above sea level. “This widespread shift to agriculture and societal development was only possible with an extra ingredient—organic fertilizers on a vast scale,” Chepstow-Lusty says.