animalphiles

Squirrels try a little snake-oil

From Reuters:
It's scary being a little, tasty squirrel, but some species of the rodents have come up with an intimidating camouflage -- snake smells.    

California ground squirrels and rock squirrels chew up rattlesnake skin and smear it on their fur to mask their scent, a team at the University of California Davis reported.

"They're turning the tables on the snake," Donald Owings, a professor of psychology who helped lead the research, said in a statement.

Barbara Clucas, a graduate student in animal behavior, watched ground squirrels and rock squirrels chewing up pieces of skin shed by snakes and then licking their fur.

The scent probably helps to mask the squirrel's own scent, especially when the animals are asleep in their burrows, they wrote in the journal Animal Behavior.

Photo: Reuters/Vasily Fedosenko

First wild footage of "Mickey Mouse" of the desert

Scientists for the Zoological Society of London have gotten the first-ever video of long-earred jerboas doing their thing in the wilds of the Gobi desert in Mongolia.

Jerboas have enormous ears on a rodent-like body and they hop around like mini-kangaroos. Unfortunately, their numbers are dwindling rapidly.

Conservationists hope it's "cute" factor will help convince the public to support preservation efforts. One biologists say the jerboa is so "charismatic" it could  become the panda of the small-mammal world, meaning it's quite marketable.

Jerboas are one of the most evolutionarily-distinct animals in the world. Dr. Jonathon Baille of the Zoological Society of London says, “It’s an extraordinary animal that looks as if it’s been designed by committee - kangaroo legs, snowshoe feet, huge ears and a pig’s nose.

Hospital takes in lame hedgehogs

From the Daily Mail:
A British animal hospital is caring for a number of lame baby hedgehogs that are casualties of the chaotic weather.

They should be asleep for the winter - but instead they are nursing their broken bones at Tiggywinkles Wildlife Hospital.

The RSPCA says its rescue centers are looking after hundreds of abandoned hedgehogs born during the exceptionally mild autumn and who are too small or weak to hibernate.

The odd weather has also led to a shortage of their favourite grubs, beetles, slugs and caterpillars.

RSPCA wildlife scientist Adam Grogan said: "They need to gain weight before they can hibernate."

Plan to rid Rat Island of rats

From Associated Press:
More than 200 years ago, rats jumped ship for Rat Island. The muscular Norway rat climbed ashore on the rugged, uninhabited island in far southwestern Alaska in 1780 after a rodent-infested Japanese ship ran aground. It was the first time rats had made it to Alaska.

Since then, Rat Island, as the piece of rock was dubbed by a sea captain in the 1800s, has gone eerily silent. The sounds of birds are missing.

That is because the rats feed on eggs, chicks and adult seabirds, which come to the mostly treeless island to nest on the ground or in crevices in the volcanic rock.

"As far as bird life, it is a dead zone," said Steve Ebbert, a biologist at the Alaska Maritime National Wildlife Refuge, whose 2,500 mostly uninhabited islands include the Aleutian chain, of which Rat Island is a part.

State and federal wildlife biologists are gearing up for an assault on the rats of still-uninhabited Rat Island, hoping to exterminate them with rat poison dropped from helicopters. If they succeed, the birds will sing again on Rat Island. And it will be the third-largest island in the world to be made rat-free.

A visitor to the island 1,700 miles doesn't have to look far to find evidence of vermin. The landscape is riddled with rat burrows, rat trails, rat droppings and chewed vegetation. Certain plants are all but gone.

The same for songbirds and seabirds.

Rats have all but wiped out the seabirds on about a dozen large islands and many smaller islands in the refuge, which is home to an estimated 40 million nesting seabirds. Puffins, auklets and storm petrels are most at risk because they leave their eggs and young for extended periods while foraging.

The rats jumped ship beginning in the late 1700s, a problem that worsened in the 1800s when Russian merchant vessels plied the islands, and grew more serious in the 1940s, when hundreds of military ships visited the Aleutian Islands during World War II.

Now, the islands are vulnerable to "rat spills" from freighters traveling the quickest route from the West Coast to Asia. The Aleutians receive about 400 port calls from vessels each year.

Rats have been the scourge of islands worldwide. According to the California-based group Island Conservation, rats are to blame for between 40 percent and 60 percent of all seabirds and reptile extinctions, with 90 percent of those occurring on islands.

"Rats are one of the worst invasive species around," said Gregg Howald, program manager for Island Conservation, which is working with the U.S. government on a plan for Rat Island.

Norway rats typically have four to six litters a year, each containing six to 12 babies. One pair of rats can produce a population of more than 5,000 rats in an area in one year.

The state is joining forces with federal wildlife biologists in a multi-pronged attack to drive the rats from Alaska.

State regulations went into effect this fall requiring mariners to check for rats and try to eradicate them if found. Violators face a year in jail and a $10,000 fine. Corporations could be fined up to $200,000.

The state also is mailing out 15,000 "Stop Rats!" brochures to educate mariners on how to control rats aboard boats and keep them from going ashore.

The brochure tells mariners to kill every rat on board, have traps set at all times, keep trash and food in rat-proof containers, use line guards — funnel-shaped devices that go around mooring lines — to keep rats from getting off or coming aboard, and never throw a live rat over the side. Rats are excellent swimmers.

The assault on the rats of 6,871-acre Rat Island could begin as early as next October. The plan — which involves the use of a blood thinner that will cause the rodents to bleed to death — still must be reviewed and sent out for public comment.

Scientists want to see how the project goes before deciding whether to try to exterminate the rats on other islands.

Fear is in the nose of the beholder

From the journal Nature:
Just a whiff of the urine from snow leopards sends shivers down the spines of normal mice. But deleting a key group of olfactory cells turns mice fearless in the face of this odor, even though the mice can still smell it, and be taught to fear it later in life.

The surprising result suggests that smells pass through distinct circuits along the path from nose to brain: one for innate fear, another for the learned kind. A single smell could activate both paths at the same time.

When a scent, noxious or pleasant, hits the nose of a mouse or any mammal, it activates a combination of olfactory neurons. Mice boast about a thousand types of these neurons, which reach from the nose to the brain. The combination of cells activated, like the notes in a piano chord, determines the scent experienced by the animal.

The olfactory neurons are located in a special structure in the nasal cavity called the olfactory epithelium, which has two major regions: dorsal and ventral To determine the difference between the dorsal and ventral neurons, Hitoshi Sakano, a neuroscientist at the University of Tokyo, and his team engineered a strain of mice that had no olfactory neurons in their dorsal epithelium. They then tested the mice for their response to a handful smells, good and bad.

Normal mice were drawn to smells of peanut butter and mouse urine; but couldn’t flee fast enough from the scents of rotting food, fox glands, and the urine of snow leopards.

But mice without these neurons showed less interest in the sweet smells and little aversion to spine-tingling ones, the team reports in Nature. The mice could still detect these smells, the researchers found, and could learn to hate the odors if researchers made the mice sick while delivering the 'nasty' smells.

The team concludes that the dorsal olfactory neurons transmit innate fear responses to the brain, whereas the ventral neurons convey learned aversion.

The work is a big step forward in explaining how odors are translated into actions, says Catherine Dulac, a neuroscientist at Harvard University in Cambridge, Massachusetts. Humans probably have a similar system for discerning smells, says Sakano. But learned behaviours can sometimes over-rule innate ones, he notes.
Photo: Ko and Reiko Kobayakawa

Rats and cats working together to save lives

Some rats are hanging out with their natural enemies in order to become better disciplined in the art of mine detection. 

There are more than 100,000 landmines planted through-out Colombia, most left by leftist rebels. Rats are better than dogs for sniffing them out, because they are light-weight enough not to trigger an explosion.

The rodents are taught to freeze in front of mines, but had difficulty staying put for fear of being attacked by predators.

So, Colombian police decided to raise the rats tolerance levels by caging them with cats. The cats wore shields on their nails so they can't injure the rats, and the two species actually play together.

The nation's rat project was recognized last month as one of the five most innovative projects at a conference of behavior psychologists in Mexico, and its initial findings will soon be presented at a similar conference in Argentina.
Photo: AP

White squirrels a hit in Norcross

There are millions of squirrels in Georgia, but one group in the Atlanta suburb of Norcross is getting more attention than most. They are white (but not necessarily albino).

There are probably three of them - and they hang out at Thrasher Park. A photo of one now appears on the city's Web site under the headline, "New mascot???"

An unidentified blogger on the site wrote these lyrics about the unusual rodents: "As far as we know it's a family of three, jumping and playing in all our trees. Seen it in the park, Seen it on my street, We all think he's pretty neat ..."

Even if the squirrel may not be very special, city clerk Susan Brooks told the Atlanta Journal Constitution folks around town seem to like the newcomer. "It just shows that there is a lot diversity in Norcross."

Capybaras, monkeys - unlikely friends

Capybaras and squirrel monkeys don't cross paths in the wild (even though both are native to South America). But some are living in the same enclosure at a Japanese zoo and they've developed a friendship of sorts.

It's a somewhat one-sided relationship. The monkeys ride on the capybara's backs and even kiss the giant rodents. The capybaras, say zoo officials, generally just tolerate the monkeys.

Since local media reported on the odd pairing, hundreds of visitors have visited the zoo to see the animals in action.

South Carolina barber "a little squirrelly"

For three years, a squirel named "Stubs" has been a daily visitor to Charlie Cox's barber shop in Charleston, South Carolina.

When she shows up, Cox stops everything he's doing to give her a peanut. Stubs (named for her short tail)  comes inside the shop and gently takes the nut from Cox's hand.

The relationship started when Cox threw some peanuts to her on the sidewalk. Stubs eventually grew more accustomed to the particularly friendly human and Cox says "we're pretty close now." He even calls her "my girl."

One customer says Cox has always been "a little squirrelly." Shop regulars are used to the daily routine. Read more about it in the Charleston Daily Mail.
photo: Tom Hindman/CDM

Climate change a "cliff" for lemmings?

Contrary to popular belief, lemmings do not commit mass suicide by leaping off cliffs into the sea. In fact, they are quite fond of staying alive. A bigger threat to the rodents is climate change, which could deprive them of the snow they need for homes and to lock up their food in ice, according to the Wildlife Conservation Society. The organization is launching a study to examine how these tiny but important players in the ecological health of the far North will fare in the age of global warming.

“We need to know how climate change will affect a variety of resident and migratory predators that rely in large part on these small arctic rodents,” said WCS Canada researcher Dr. Don Reid. “The ability of lemmings to adapt to these changes will have a significant impact on the entire food web, so we need to understand more about lemming ecology within the context of climate change.”

Lemmings serve as an important prey species for a number of predators, including arctic foxes, red foxes, rough-legged hawks, peregrine falcons, snowy and short-eared owls, jaegers, gulls, weasels, wolverines, and grizzly bears. In fact, the population of many predators fluctuates in response to dips in lemming numbers. One of the key ingredients for lemming abundance and productivity is likely snow. Sufficient snow depth insulates the rodents from frigid temperatures, allowing them to devote more energy to breeding and less to avoiding predators.  Later arrival of autumn snows, and earlier spring melts, could subject lemmings to longer periods of sub-freezing temperatures. Also, the tundra is experiencing unusual warm periods in winter, including freezing rain and episodes of thawing and freezing, which can coat much of the lemmings’ foods (sedges and dwarf shrubs) in ice.

Lemming predators also have to adapt to these changes.  Predators that specialize on eating lemmings, such as snowy owls and arctic foxes, may suffer if lemmings are no longer so productive.   Other predators may benefit.  For example, there is evidence that red foxes have usurped considerable areas from arctic foxes in recent decades.  Warmer temperatures may have increased the productivity of the red foxes’ diverse prey (ground squirrels, birds and lemmings), and improved their ability to survive the tundra winters. Researchers will investigate these possibilities, and track the productivity of foxes and raptors for comparison to historic data.