Elephants Out-compete Rhinos at Salad Bar

http://animalzoon.blogspot.in/

Elephants get first dibs at the African savannah salad bar, which may force rhinos to dine on lower quality food and a more limited diet.

When elephants abound in an ecosystem, a South African study found that black rhinos (Diceros bicornis) tend to eat more grass than in nearby areas with fewer elephants. Grass contains more fiber per the amount of energy it contains, and thus provides rhinos with less nutrition per pound than other floral food sources.

However, when African elephants (Loxodonta africana) are absent, an analysis of rhino poop found evidence that the horn-headed herbivores devour a wider variety of vegetation, including leaves from shrubs, succulent plants and liana vines.

Top 10 Things Poop Makes Better

“Despite extensive evidence of the effects of elephant on food resources in the Addo Elephant National Park (where the study was conducted) and elsewhere few studies have investigated the consequences of this for other large herbivores,” wrote the authors in the journal PLOS ONE. “Surprisingly, where this information exists, the emphasis has been on demonstrating that elephant facilitate herbivore access to habitat and increase the availability and quality of food. This is despite clear evidence that elephants limit herbivore abundances across ecosystems through their ability to monopolize resources.”

The elephant-enforced diet may harm rhino health. Analysis of the chemical composition of rhino droppings found that levels of the important nutrient phosphorus were lower in rhinos living in areas where pachyderms predominated.

Geese Police and Other Crime-Fighting Critters

http://animalzoon.blogspot.in/

An elite gaggle of geese “police,” is now employed to ward off troublemakers in China’s rural Xinjiang province. But they're just the latest example of unexpected security animals hard at work around the world.

The geese are “extremely vigilant” and seem to be “better than dogs” at preventing crime, says Zhang Quansheng, a police chief in Xinjiang’s Shawan county.

Male Fish Lure Females With Genital Claws

http://animalzoon.blogspot.in/

When male guppies fail to win over females with their good looks and dance moves, they turn to another, more aggressive set of tools: claws on the tips of their genitalia.

The Weirdest Animal Penises
The diversity of evolution is downright amazing, and we're not just talking wings and eyeballs -- we're talking animal penises!
DCI
Biologists have long speculated that guppies — freshwater fish native to the Caribbean — use tiny claws on the tips of their genitalia to secure mates. But, until now, nobody has tested this theory experimentally. A group of biologists from the University of Toronto conducted an experiment to test the role of the claws in mating, and found that the grippers helped males seal the deal with females that were otherwise unwilling to mate, the researchers report today (July 23) in the journal Biology Letters.

At first, male guppies take on a peaceful approach to mating and put on a bit of a show to attract females. When they are lucky, the females willingly approach them when the show is over. [Top 10 Swingers in the Animal Kingdom]

Amazing Nature Photos That Will Blow Your Mind
"The male will display to the female, extending his body in an S shape and then shimmering, showing these bright spots," said Lucia Kwan, a graduate student at the University of Toronto and a co-author of the report. "If the female is receptive, she glides over to the male."

But, if females don't show interest, males continue to pursue them. They sneak around the female from behind or below, and try to force sperm into her without her cooperation. This behavior is common in guppies in the wild, Kwan said.

To test the role of claws in this mating tactic, the team used a scalpel to slice off the claws from a subset of test guppies, leaving the claws intact in the rest of the test group for comparison. They then placed each male in a tank with a virgin female and waited up to two hours to observe mating behavior. At the end of each trial, the team extracted the females from the tanks and dissected them, removing and quantifying the amount of sperm within each female.

Less Ice Equals More Seal Strandings

http://animalzoon.blogspot.in/

Harp seals mate and rear their young on the sea ice off the east coast of Canada in the spring and move north as the weather warms. But increasing numbers of seals are ending up stranded along the U.S. East Coast, as far south as the Carolinas, far away from where they should be at this time of year.

The Ocean Is In Danger!
A look at the dire state of perhaps the most interesting and diverse part of our planet.
STOCKBYTE/GETTY IMAGES
As ice levels in the North Atlantic have declined, the number of seals that have wound up on beaches, either dead or in poor health, has increased, new research shows.

The study, published this month in the journal PLOS ONE, suggests that the decline of sea ice is at least partially responsible for the increase in seal strandings, said Brianne Soulen, a study co-author and biologist at the University of North Texas. Demographic factors also play a major role: A large portion of stranded seals are young, and the majority (62 percent) are male, said Soulen, who performed the research while a graduate student at Duke University. [Gallery: Seals of the World]

On Earth's Cold Edge: Photos
Males may be more likely to get stranded because they tend to wander farther afield once on their own, Soulen told LiveScience.

The study was able to mostly rule out the possibility that strandings are due to inbreeding, finding that stranded seals are just as genetically diverse as non-stranded seals.

"Genetics didn't seem to have an influence," Soulen said.

The snow-colored harp seals mate and give birth on sea ice, then mothers nurse and stay with their young. After that, the pups are on their own. The researchers hypothesize that in years with less ice, the ice that exists becomes crowded, and some seals are forced into the water before they've learned how to navigate or how and where to fish, Soulen said. This may lead them to follow groups of fish moving south, or allow them to become disoriented, she added.