Archives of animal science blog

 

Archives of animal science blog

April 21, 2007, 8:25 AM CT
Lemmings And Global Warming

                                                                                               

Credit: Don Reid/Wildlife Conservation Society
Contrary to popular belief, lemmings do not commit mass suicide by leaping off of 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 lock up their food in ice, as per the Wildlife Conservation Society, which 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 many 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 a number of 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.........

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April 21, 2007, 7:34 AM CT
Not Your Average Easter Bunny

                                                                                                 

Sumatran striped rabbit
© WCS
Hippity, hoppity.....click! One of the world's rarest rabbits hopped in front of a camera trap planted by Wildlife Conservation Society (WCS) scientists in an Indonesian rain forest. The photos, taken in Bukit Barisan National Park, are only the third images of the Sumatran striped rabbit ever recorded; the rabbit was last photographed there in 2000.
Before the first photo was taken in 1998, the foot-long Sumatran striped rabbit had not been seen alive since 1972. Only 15 specimens exist in museums, all dating from before 1929. The rabbit is only known to inhabit the forested, mountainous spine of its island namesake. It is listed by the World Conservation Union (IUCN) lists as Critically Endangered.

"This rabbit is so poorly known that any proof of its continued existence at all is great news and confirms the conservation importance of Sumatra's forests," said Colin Poole, director of WCS's Asia Program.

Until recently, the Sumatran striped rabbit was believed to be the sole representative of its genus. In 1999, however, scientists discovered another striped rabbit in the Annamite Mountains, which straddle Lao PDR and Vietnam. Eventhough the two species resemble each other, genetic samples revealed them to be closely related but distinct, having diverged about 8 million years ago.........

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April 21, 2007, 7:13 AM CT
Tracking Six-Week-Old Tiger Cubs

                                                                                    
Researchers from the Wildlife Conservation Society (WCS) and their Russian colleagues from the Sikhote-Alin Reserve have fitted three six-week-old Siberian tiger cubs with tiny radio collars (below). They are the youngest wild tigers ever to be tracked by scientists. The collars--made of expandable elastic and designed to fall off the cubs as they grow--weigh just over five ounces and would fit well on a large housecat. Radiotracking has given scientists crucial insights into the lives of tigers in the Russian Far East and has led to methods to improve the survival and reproduction of the largest of the cat species.
"Through radio-telemetry, we've learned a great deal about the needs of Siberian tigers, animals so elusive that few field scientists have seen them in their natural habitat," says WCS biologist John Goodrich (left), who heads the Siberian Tiger Project. "Now we can finally get some idea of what causes the deaths of tiger cubs, which suffer a mortality rate of nearly 50 percent in their first year. If we can somehow improve their chances, we can make a big difference in helping the population grow."

The radio transmitters emit a "mortality" signal if the unit remains stationary for more than one hour. Finding an animal quickly is crucial in determining cause of death.........

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April 21, 2007, 6:58 AM CT
Uganda's mountain gorillas

Image courtesy of geoex.com

                                                                                  
The most recent census of mountain gorillas in Ugandas Bwindi Impenetrable National Parkone of only two places in the world where the rare gorillas existhas observed that the population has increased by 6 percent since the last census in 2002, as per the Uganda Wildlife Authority, the Wildlife Conservation Society, the Max Planck Institute of Anthropology and other groups that participated in the effort.

This is great news for all of the organizations that have worked to protect Bwindi and its gorilla population, said Wildlife Conservation Society researcher Dr. Alastair McNeilage, who is also the director of the Institute of Tropical Forest Conservation in Bwindi. There are very few cases in this world where a small population of a endangered primates is actually increasing.

As per the census, which also successfully used for the first time genetic samples from fecal specimens, Bwindis gorilla population now numbers 340 individual gorillas, up from 320 in 2002, and 300 in 1997.

The census was conducted between April and June 2006 to determine the size and makeup of the Bwindi population, in addition to their distribution and to gauge human impacts on the gorillas. During that time, survey teams set out with the intention of counting every family group in the population, a method possible only with small animal populations in a relatively small area; Bwindi Impenetrable National Park is approximately 127 square miles in size.........

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April 19, 2007, 8:12 PM CT
Bison Calf

                                                                            
Springtime means the coming of new life for most animals. From the moment of birth, life for animals in Wind Cave National Park is a constant fight for survival. Fortunately, animals are born with certain protective mechanisms.

Bison Calf

This May 50 to 60 bison calves will be born to Wind Cave's herd of about 350 bison. Most cows give birth to one calf each year. Two or three days after the birth the seventy pound, red-coated youngsters will roam with the herd. As bison are gregarious creatures, group protection of calves creates a safe environment. A bison is fully mature at two years.........

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April 19, 2007, 7:49 PM CT
New Deep-Sea Hydrothermal Vents

                                                                                                             

A new type of jellyfish has been discovered at deep-sea hydrothermal vents in the Pacific Ocean.

                                                                               
Credit: WHO                                                                     
A new "black smoker"--an undersea mineral chimney emitting hot springs of iron-darkened water--has been discovered at 8,500-foot depths by an expedition funded by the National Science Foundation (NSF) to explore the Pacific Ocean floor off Costa Rica.

                                                                                            
Researchers from Duke University, the Universities of New Hampshire and South Carolina, and the Woods Hole Oceanographic Institution in Massachusetts have named their discovery the Medusa Hydrothermal Vent Field.

The scientists chose that name to highlight the presence there of a unique pink form of the jellyfish order stauromedusae. The jellyfish resemble "the serpent-haired Medusa of Greek myth," said expedition leader Emily Klein, a geologist at Duke University.

The bell-shaped jellyfish sighted near the vents may be of a new species "because no one has seen this color before," said Karen Von Damm, a geologist at the University of New Hampshire.

As per Von Damm, stauromedusae are commonly found away from high-temperature hydrothermal vents, where the fluids are a little bit cooler, not close to the vents as these are.

Aboard the Research Vessel (R/V) Atlantis, the scientists are studying ocean floor geology of the East Pacific Rise, one of the mid-ocean ridge systems where new crust is made as the earth spreads apart to release molten lava.........

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April 19, 2007, 7:31 PM CT
New Genus Of Frogmouth Bird In Solomon Islands

                                                                                                             

A new genus of frogmouth bird is seen in the top right of this photograph taken April 18, 2007. It was found in the Solomon Islands by Florida Museum of Natural History ornithologists Andrew Kratter and David Steadman.

Your bird field guide may be out of date now that University of Florida researchers discovered a new genus of frogmouth bird on a South Pacific island.

New genera of living birds are rare discoveries - fewer than one per year is announced globally. David Steadman and Andrew Kratter, ornithologists at the Florida Museum of Natural History, turned up the surprising new discovery on a collecting expedition in the Solomon Islands. Theirs is the first frogmouth from these islands to be caught by researchers in more than 100 years. They immediately recognized it was something different.

Kratter and Steadman are co-authors to a study analyzing the frogmouth's morphology, or physical form, and DNA compared to two other living genera of frogmouths. The findings appear in the April print edition of Ibis: The International Journal of Avian Science, in a paper that describes the bird as a new genus and species, now named Rigidipenna inexpectata.

"This discovery underscores that birds on remote Pacific islands are still poorly known, scientifically speaking," Steadman said. "Without the help of local hunters, we probably would have overlooked the frogmouth".

Originally, the bird was misclassified as a subspecies of the Australian Marbled Frogmouth, Podargus ocellatus. The blunder went undetected for decades, until a collecting trip led by Kratter in 1998 turned up a specimen on Isabel, a 1,500-square-mile island in the Solomons. Today, the only museum specimen of this bird in the world, with an associated skin and skeleton, is housed at the Florida Museum.........

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April 19, 2007, 7:26 PM CT
Why some aphids can't stand the heat

                                                                                                                                                                                                           

Mother Giving Birth
A pea aphid, Acyrthosiphon pisum, gives birth to a baby aphid
Credit: Copyright 2007 Nancy A. Mor
For pea aphids, the ability to go forth and multiply can depend on a single gene, as per new research.
An overheated aphid with a mutation in that gene can't reproduce.

The gene isn't even in the insect -- it's in tiny symbiotic bacteria housed inside special cells inside the aphid.

"It's the first time a mutation in a symbiont has been shown to have a huge impact on host ecology," said Nancy A. Moran, Regents' Professor of ecology and evolutionary biology at The University of Arizona in Tucson. "One version of the gene is good if the aphids experience heat, and the other version is good if they are in cool conditions".

Neither organism can survive on its own. The Buchnera aphidicola bacteria, which cannot live on their own, supply the aphids, Acyrthosiphon pisum, with essential nutrients.

UA scientists Helen E. Dunbar, a senior research specialist, Alex C. C. Wilson, now at the University of Miami in Coral Gables, Fla., Nicole R. Ferguson, a member of UA's Undergraduate Biology Research Program, and Moran are publishing their findings in the May 2007 issue of PLoS Biology.

Their research paper is titled "Aphid Thermal Tolerance is Governed by a Point Mutation in Bacterial Symbionts." The research was funded by the National Science Foundation and the National Institutes of Health. Howard Hughes Medical Institute provides funding for the UA's Undergraduate Biology Research Program.........

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April 17, 2007, 5:00 AM CT
Unraveling Intricate Animal Patterns

                                                                                                                                                                             
There is a scene in the animated blockbuster "Finding Nemo" when a school of fish makes a rapid string of complicated patternsan arrow, a portrait of young Nemo and other intricate designs. While the detailed shapes might be a bit outlandish for fish to form, the premise isnt far off. But how does a school of fish or a flock of birds know how to move from one configuration to another and then reorganize as a unit, without knowing what the entire group is doing? New research by University of Alberta researchers shows that one movement started by a single individual ripples through the entire groupa finding that helps unravel the mystery that has plagued researchers for years.

"It is known that there is a correlation between the signals animals use to communicate with each other and their behaviour," said Raluca Eftimie, a graduate student in the U of As Centre for Mathematical Biology. "But until now, the correlation between the complex spatial group patterns that we can see in nature and the different ways animals communicate, has not been stated explicitly".

For decades people have puzzled about how animalsfish schools, locust swarms, large flocks of birds--form large complex dynamical groups. It is clear individuals in the group are only communicating with nearby neighbours, but then the groups somehow emerge spontaneously with complicated patterns of their own. Eftimie and her co-authorsDr. Mark Lewis and Dr. Gerda de Vries, also from the Centre for Mathematical Biology housed in the U of As Department of Mathematical and Statistical Sciences--used a one-dimensional mathematical model to describe the formation and movement of animal groups. The work is reported in the prestigious journal, "Proceedings of the National Academy of Sciences".........

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April 17, 2007, 4:57 AM CT
The cost of long tongues

                                                                                                          

Orchid bee Eulaema
Credit: G. Dimijia
Orchid bees use their extraordinarily long tongues to drink nectar from the deep, tropical flowers only they can access. Scientists have long suspected that this kind of exclusive access came with a mechanical cost. As per common sense and a classic law of fluid mechanics, it's just plain hard to suck thick, viscous nectars up through a long straw. Now, Brendan Borrell at the University of California, Berkeley has confirmed this prediction for the first time: orchid bees with long tongues suck up their nectars more slowly than bees with shorter tongues.

Borrell spent three years collecting bees in forests all over Costa Rica and Panama and measuring their feeding rates at artificial flowers. He observed that the smallest bees sometimes had the longest tongues and the largest bees sometimes had the shortest tongues. But after taking into account all that variation in body size, he says long tongues really do impose a mechanical cost on bees. Everyone knows just how busy bees can be, but orchid bees are basically sacrificing speed at flowers for exclusive access to them. Borrell thinks this may be because the rewards at these flowers can be tremendous, up to ten times the quanity of nectar provided by typical bee flowers.........

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Excerpted from Archives of animal science blog
http://www.biology-blog.com/blogs/archives/Animal-science-blog/1798365085-May-17-2007.html
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Date - Jan - 29 - 2011.