Thursday April 25, 2013
The more stressed a mother squirrel is, the stronger and more robust the offspring she produces are, a new study by researchers from the Univeristy of Guelph in Ontario reveals. During pregnancy and after young are borne, female squirrels listen for cues about their social environment.
In crowded environments were squirrel populations are dense, female squirrels pick up on more frequent and louder rattles and calls (sounds made to declare territory). In response to these sounds, the females produce higher levels of stress hormone. In areas where squirrel populations are dense, the fastest growing squirrels are more likely to survive. When female squirrels were fed peanut butter with added sress hormontes, their pups grew faster than pups of females with low stress hormones. The study shows that despite the many negative aspects of stress, in some cases it can result in benefits.
Photo © Ryan Taylor / Univeristy of Guelph.
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Thursday April 25, 2013
Think Elephants International, an organizaton that promotes elephant conservation through research and education, joined forces with 12-14 year old students at East Side Middle School in New York City to design and conduct an experiment on how elephants perceive the world around them. The study focused on how elephants process visual clues made by humans and also examined how elephants responded to vocal commands. The study found that elephants do not easily interpret visual clues such as pointing. Instead, they process vocal commands more successfully.
The findings are important because they can contribute to better conservation strategies for protecting elephants. If elephants do not use visual information as a primary method of navigating their environemnt, we need to understand better what kind of information they do use whether it be, for example, sound or smell.
Conservationists at Think Elephant point out the importance of elephant conservation and estimate that without intervention in the next fifty years we could see elephants become extinct. Think Elephant plans to extend similar research programs to involve sutdents at schools in Thailand.
Photo © Paula Bronstein / Getty Images.
Tuesday April 23, 2013
A recent study has revealed that the Asian subspecies of great bustard, one of the world's heaviest birds, migrates over 2,000 miles round-trip between its breeding grounds in northern Mongolia and its winter range in Shaanxi province, China. The discovery was made by a team of scientists led by Arizona State University biologist Mimi Kessler.
The research team spent two years in Eurasian grasslands studying many aspects of the great bustards' biology including the birds' habitat use, population genetics, causes of mortality and migration routes. Kessler and colleages carefully captured and fitted several great bustards with GPS transmitters so they could track the birds' migratory routes and for the first time find out how far the various populations of great bustards travelled each year.
They discovered that the various subspecies migrate different distances based on the climates they inhabit. The great bustards that live in Spain migrate less than a dozen miles each year; those in western Russia migrate about 600 miles each way between winter and breeding seasons. The Asian great bustards that breed in Mongolia, are the longest migrating subspecies, covering an impressive 1200 miles each way between breeding and wintering grounds.
Male Asian great bustards can weigh up to 35 pounds, while females are much smaller, weighing up to 11 pounds. The Asian subspecies is threatened and is declining due to poaching for sport and meat. They also face threats along their migratory route due to collissions with power lines and cables.
Photo © B.S. Chun / ASU.
Monday April 22, 2013
In 1938, a local fish trawler delivered a handful of fish specimens he had recently caught to a small natural history museum in East London, South Africa. The curator of the museum, Marjorie, courtenay-Latimer, examined the specimens and one in particular caught her eye. It was over a meter long, bluish in color and had fleshy fins that looked similar to the limbs of a frog or other terrestrial vertebrate. The species is today known as the African coelacanth, a member of a group of fish that was, until 1938, thought to have become extinct over 70 million years ago. The fact that a living specimen of coelacanth had been discoverd was remarkable. The discovery is considered among the most important zoological finds of the twentieth century.
Now, a team of scientists from the A*STAR Institute of Molecular and Cell Biology and their colleagues have sequenced the genome of the African coelacanth and in doing so have opened the way for a deeper understanding of the evolution of early tetrapods.
The fossil record suggests that coelacanths have changed little during the the past 300 million years. An understanding of the coelacanth's genetic profile gives scientists a glimpse back in time to better decipher the development of fins, tail, ear, eye, brain and olfaction systems in early terrestrial vertebrates.
Coelacanths are large fish that live in deep sea caves. They are most notable for their fleshy fins, which resemble the limbs of land vertebrates. In 1997, a second species of coelacanth was discoverd in Indonesia.
Photo © Institute of Molecular and Cell Biology.