« May 2007 | Main | July 2007 »
One-month-old baby hippopotamus Paul made his first public appearance
at Berlin Zoo Friday.
The BBC Web site, where this picture comes from, suggests Paul may pull attention away from the hugely popular polar bear Knut. Paul's looks alone may not be able to achieve that, but Knut is growing fast (he's six-months-old now) and rapidly losing the heart-melting adorableness of his youth.
Most folks just assume all bats are blind because of a certain maxim. But scientists have long known fruit bats are the exception - having decent night vision. And now, new research shows they see pretty well during daylight hours too.
First, a primer on how vision works: For most mammals, the eye's retine has two types of photoreceptor cells, or neurons that absorb the light. Cones, are used for daylight and color vision, while the more sensitive rods are used for night vision.
Many nocturnal bats are, in fact, blind. They have only have rods (which are overwhelmed by the intense light of day) and use echolocation to get around a find food.
But fruit bats fly at twilight and occasionally during the day, prompting scientists to speculate they must have some cones in their eyes.
Researchers stained the retinas of several fruit bat species and found that, while the number of cones is small, they do exist.
The fruit bats’ daylight-sensitive cones help them stay alert to predatory birds while they roost in large open treetops during the day, but come dinnertime, the more sensitive rods are still the go-to photoreceptors.
Photo:Dana LeBlanc, Lubee Bat Center
A tiny critter is causing a huge sensation at the Tennessee Aquarium. It's a rare Beal's four-eyed turtle, named for two white spots on the
back of its head that look like another pair of eyes.
Reptile experts at the Chattanooga facility say the turtle "may represent the first successful reproduction of Sacalia bealei in a North American institution."
The baby turtle weighed only two-tenths of an ounce and was one-and-a-half inches long when it hatched June 9. It will not be put on display until it is much older.
There are only 18 known Beal's four-eyed turtles in the United States and Europe.
Only two of the twenty Columbia Basin pygmy rabbits released into the wild in March remain in the release area in central Washington. Luckily it was one male and one female, and researchers say they have done what rabbits do best - breed.
They had to dodge coyotes, badgers, hawks and other predators but still found time to start a family. A researcher found the female digging a burrow and lining it with grass, an indication she was preparing to give birth - and later spotted a juvenile rabbit near another burrow from what is believed to be a second litter of babies.
The Sagebrush Flat Wildlife Area where the captive rabbits were released is considered the last native home of the Columbia Basin pygmy rabbit. The rabbit was listed as a state endangered species in 1993 and protected under the federal Endangered Species Act in 2003.
The reasons the Columbia Basin rabbits declined are not precisely known, although scientists suspect inbreeding among such a small population was a major factor. Range fires, farming, disease and predators also are thought to have taken their toll.
Washington State University, the Oregon Zoo and Northwest Trek near Tacoma, working with the Washington Department of Fish and Wildlife and the U.S. Fish and Wildlife Service, are raising between 75-100 pygmy rabbits for eventual release. One is scheduled for this fall, and additional steps will be taken to protect the females, such as erecting fences or cages around burrows to keep predators out.
Today's backyards look very different than 40 years ago - because once common birds aren't as plentiful.
A new analysis shows the populations of 20 common birds, including meadowlarks, pintail ducks and bobwhites are half what
they were in the 1980s.
The National Audubon Society blames suburban sprawl, climate change and other invasive species. Many of the species listed as declining in the new study depend on open grassy habitats that are disappearing.
Some of the birds, such as the evening grosbeak, used to be so plentiful that people would complain about how they crowded bird-feeders and finished off 50-pound sacks of sunflower seeds in just a couple days. But the colorful and gregarious grosbeak's numbers have plummeted 78%.
Affected species include the northern pintail, greater scaup, boreal chickadee, common tern, loggerhead shrike, field sparrow, grasshopper sparrow, snow bunting, black-throated sparrow, lark sparrow, common grackle, American bittern, horned lark, little blue heron and ruffed grouse.
The northern bobwhite had the biggest drop among common birds. In 1967, there were 31 million of this distinctive plump bird. Now they number closer to 5.5 million.
While these common birds are in decline, others are taking their place or even elbowing them aside. The wild turkey, once in deep trouble, is growing at a rate of 14 percent a year. The double-crested cormorant, pushed nearly to extinction by DDT, is growing at a rate of 8 percent a year and populations of the pesky Canada goose increase by 7 percent yearly. The Eurasian collared-dove, which first entered Florida in the 1980s, it now is the most prevalent bird in the Sunshine State and is in more than 30 states.
A deaf Atlantic bottlenose dolphin delivered her calf this week at the Marine Mammal Conservancy in the Florida Keys. The calf is 42 inches long and weighs about 30
pounds.
The mother, Castaway, has been vocalizing to the calf and the baby has answered back. But vets believe Castaway cannot process the baby's sounds.
The mama dolphin vocalizes in a monotone, much like deaf humans speak. In order for the calf to become properly socialized with dolphin language, vets have wired the nursery with sound - electronically connecting to a lagoon at Dolphins Plus a few miles away.
Mother and calf are to remain at the Conservancy for at least six months before relocating to a more permanent facility.
A new study says the world's wild tigers are on a
"catastrophic" path to extinction - because of increased poaching, habitat destruction and
poor governmental conservation efforts.
The big cats currently occupy a mere 7% of their original homelands. Some former habitats, like the Caspian region, Bali and Java have no more tigers at all.
The report, titled "The Fate of Wild Tigers," is published in the journal BioScience. It says tigers as a species are not likely to go extinct within the next half-century, but wild populations are on track to disappear from many more places.
Despite widespread trade bans, poaching remains a serious
problem where products made from tigers, such as skins and
bones used in traditional Chinese medicines, are coveted by
consumers in China, Japan, South Korea, Vietnam and the United States. The greatest threat could be China's plans to lift its 1993 ban on the domestic trade
of tiger parts.
The report calls for an international "tiger summit" aimed at securing a global pledge to protect the wild heritage of Asia.
Elephants don't need to put their ear to the ground to hear far-away sounds. They can just use their feet.
A report in New Scientists say it's a common practice, but elephants react most if the calls they hear come from elephants they know.
Elephants are already known for their ability to emit low-frequency sounds to communicate with herds up to several miles away.
Researchers led by Caitlin O'Connell-Rodwell of Stanford University Medical Center in California also suspected that these rumblings generate seismic waves that travel through the ground, enabling elephants to pick up the signals through their surprisingly sensitive feet.
Her team recorded alarm calls in Namibia and Kenya made by elephants when lions were lurking.
They then played just the seismic portion of the sound through the ground to herds at watering holes in Namibia.
The elephants "reacted dramatically, first freezing and then clumping in tight groups, with babies in the middle," the British weekly reports in next Saturday's issue.
But the farther the elephants lived from the herd which made the call, the less they reacted.
The study is to be published in the Journal of the Acoustical Society of America, New Scientist says.
photo:AFP/DDP/Marcus Brandt
A new study estimates at least 400 species of birds could become endangered within the next
50 years because of global warming , deforestation and the conversion of grassland to crop fields.
“We found in our study that under certain assumptions by the year 2100, 950 to 1,800 bird species may be imperiled or even driven to extinction by climate change and habitat destruction,” said lead author Walter Jetz of the University of California, Davis. “Most of these species are currently not recognized as imperiled.”
Climate change will be the primary driver of extinctions at higher latitudes, as suitable habitats begin to shrink, the authors state.
For tropical birds, direct habitat destruction will be more of a problem: birds in tropical climates tend to be highly specialized to small habitat ranges. As soon as their home is gone, they have nowhere to go.
The projections from the Millennium Ecosystem Assessment are detailed in the online journal PLoS Biology.
photo:stock/xchng
While
promiscuity in the animal kingdom is generally a male thing,
researchers for the Wildlife Conservation Society and the Zoological
Society of London (ZSL) have found that, in cheetah society, it’s the
female with the wandering eye.
Researchers
found that about 43 percent of cheetah litters with more than one cub
were fathered by more than one male. “It seems that female cheetahs are
highly promiscuous with no detectable mate fidelity between breeding
seasons,” said Dr. Sarah Durant, a researcher with the Wildlife
Conservation Society/Tanzania Cheetah Conservation Program and project
leader.
Female cheetahs occupy a home range averaging some 833 square kilometers in size, whereas a male’s territory averages 37 square kilometers. In many carnivore species, it’s the males that have larger ranges that encompass several female ranges.
“The picture that emerges is that of wide-ranging females mating with a number of males, which could be an advantage in terms of helping to maintain genetic diversity,” said ZSL’s Dada Gottelli, the study’s lead author.
Findings from the study are significant for conservation efforts for the species, which is threatened by a number of human-related causes. Further, cheetahs have always existed in low densities, due to competition from larger predators such as the lion and hyena. “Our study shows that more fathers are contributing to the next generation than we thought,” added Durant. “This is good news for cheetahs, and a reminder that future conservation strategies need to encompass large landscapes if females are to continue to have access to many males.”
