News on Animals By Cathy Chang Snakes Starting Questions What are the characteristics of snakes? Do you see them as essential to the environment or just dangerous reptiles? How is the image of snakes usually used in places like books, movies, etc.?
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By Cathy Chang
The diverse and deadly array of venomous snakes living today all arose from a single fanged ancestor, a new study suggests.
Vipers, cobras, and other snakes that have fangs at the fronts of their jaws surprisingly begin life like snakes that have poisonous fangs at the back of their jaws, said a team led by Freek Vonk of Leiden University in the Netherlands.
The discovery suggests venomous fangs--the lethal evolutionary invention that led to snakes becoming so successful--arose only once about 60 million years ago.
The origins of venom-injecting snakes have long been the source of scientific controversy, because the contrasting fang positions of diverse snake groups pointed to independent evolution.
But a study of the embryos of eight front- and rear-fanged species has found that fangs always first appear at the back of the upper jaw before migrating forward in vipers and cobras.
This previously unidentified transformation in the unborn young occurs due to "rapid growth of some parts of the upper jaw relative to the others," Vonk explained. (Source)
Young female red-fronted lemurs in Madagascaradopt male coloration to dupe their aggressive female group-mates, a new study found.
These "cross dressing" primates thus avoid the wrath of older females, which would attack them to reduce sexual competition.
All red-fronted lemurs are born with the same grayish brown fur and rusty-red crowns that distinguish adult males.
At 7 to 17 weeks later, females' coats change to a cinnamon hue, and their crowns become white.
"We knew from our longer-term observations that there was a lot of female aggression in red-fronted lemurs," said study author Claudia Fichtel of the University of Göttingen's German Primate Center.
"Females compete fiercely over limited breeding opportunities, and we wanted to know if hiding femininity was a way to avoid being attacked," Fitchtel said. (Source)
After years of being attacked by crows, a colony of seabirdsnesting in Tokyo is getting an unlikely ally: the tiny honeybee.
Conservationists hope bees will repel the crows, based on the insects' tendency to attack anything dark-colored that approaches their hives.
This year beehives from rural areas were relocated to the top of a large water-treatment facility near Tokyo's international airport, where as many as 4,000 birds known as little terns nest after a long migration from Australia, New Zealand, and Papua New Guinea.
Although they are not endangered internationally, little terns are listed as "vulnerable" in Japan's Red Data Book of threatened species.
That's because the terns' nesting sites in the country are being destroyed by construction work and other human activities, so the birds are considered potentially at risk in the future.
The terns near the airport have long been victims of Tokyo's crows.
Members of a rare chameleon species all hatch in the same month, then die only four to five months later--making them the shortest-lived four-limbedvertebrates, a new study says.
Labord's chameleon had been identified in 1872 in the arid southwest of the island of Madagascar off the east coast of Africa. But it wasn't until 2003 that a zoologist noticed there was something strange about this particularspecies.
"It was just bizarre, because I could find only adults and no juveniles whatsoever," said study co-author Kristopher Karsten of Oklahoma State University.
"So I thought, Well, either my eye isn't trained very well to find these juveniles, or they're not there. And if they're not there, maybe that means that every one is the same age and they're an annual species.
"After studying the chameleons for three more seasons, Karsten and his colleagues were certain that the entire population of Labord's chameleon (Furcifer labordi)turns over every year.
Like avid travelers picking up local languages, migrating birds appear to learn and understand the common calls of unrelated bird species that they encounter during their long journeys, new research reveals.
Birds that remain in one location throughout the year have no difficulty identifying predators, such as hawks, ferrets, and snakes.
Migrators, however, constantly face the threat of encountering predators in their travels that they do not immediately recognize as dangerous.
Some ecologists had previously suggested that long-distance travelers pick up cues from local species to obtain information on unfamiliar predators, but evidence for this theory has been thin.
To explore the possibility, researchers at Queen's University in Ontario, Canada, played predator warning calls made by both local and foreign species to birds passing through Belize on long migrations as well as to local birds and monitored their reactions.
“Animal News.” National Geographic. 1 Aug 2008. <http://news.nationalgeographic.