Posts Tagged ‘Mammals’

Bee Species Outnumber Mammals And Birds Combined

June 18, 2008

Scientists have discovered that there are more bee species than previously thought. In the first global accounting of bee species in over a hundred years, John S. Ascher, a research scientist in the Division of Invertebrate Zoology at the American Museum of Natural History, compiled online species pages and distribution maps for more than 19,200 described bee species, showcasing the diversity of these essential pollinators. This new species inventory documents 2,000 more described, valid species than estimated by Charles Michener in the first edition of his definitive The Bees of the World published eight years ago.

“The bee taxonomic community came together and completed the first global checklist of bee names since 1896,” says Ascher. “Most people know of honey bees and a few bumble bees, but we have documented that there are actually more species of bees than of birds and mammals put together.”

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Mammalian Neurogenesis Breaks Into The Most Static Brain Region

June 9, 2008

Fifteen years ago, the discovery of adult neurogenesis (the production of new neurons) in the highly static, non-renewable mammalian brain was a breakthrough in neuroscience. Most emphasis was put on the possibility to figure out new strategies for brain repair against the threath of neurodegenerative diseases. Yet, unlike lower vetebrates, which are characterized by widespread postnatal neurogenesis, neurogenic sites in mammals are highly restricted within two very small regions. Hence, the fact that protracted neurogenesis in mammals is an exception rather than the rule slowes down hopes for generalized brain repair.

Work carried out in the recent past at the University of Turin, involving Federico Luzzati and Paolo Peretto at the Department of Animal Biology, and Giovanna Ponti and Luca Bonfanti at the Department of Veterinary Morphophysiology, revealed striking examples of structural plasticity and neurogenesis in the nervous system of rabbits. These Lagomorphs show remarkable differences under the profile of neurogenesis with respect to their close relatives Rodents (mice and rats).

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New Zealand Bird Outwits Alien Predators

June 8, 2008

New research led by Dr Melanie Massaro and Dr Jim Briskie at the University of Canterbury, which found that the New Zealand bellbird is capable of changing its nesting behaviour to protect itself from predators, could be good news for island birds around the world at risk of extinction.

The introduction of predatory mammals such as rats, cats and stoats to oceanic islands has led to the extinction of many endemic island birds, and exotic predators continue to threaten the survival of 25 percent of all endangered bird species worldwide

[…] But their study on the bellbird, an endemic New Zealand bird, has identified the ability of a previously naïve island bird to change its nesting behaviour in response to the introduction of a large suite of exotic mammalian predators by humans.

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Memory In Honeybees: What The Right And Left Antenna Tell The Left And Right Brain

June 8, 2008

It is widely known that the right and left hemispheres of the brain perform different tasks. Lesions to the left hemisphere typically bring impairments in language production and comprehension, while lesions to the right hemisphere give rise to deficits in the visual-spatial perception, such as the inability to recognize familiar faces.

In the last few years, we have become used to the idea that functional asymmetry between the left and right sides of the nervous system is not unique to humans: fishes, amphibians, birds and mammals have functional and anatomical asymmetries.

So, the idea that all vertebrate species, even non-human ones without any linguistic skills, have an asymmetric brain seems to be finally accepted. Now, this process of extension among species is going on and brain lateralization has been extended beyond the class Vertebrata. Insects, with their nervous system so different from that of vertebrates, are also “lateralized”, as shown in a paper published in PLoS ONE by Lesley J. Rogers of the Centre for Neuroscience and Animal Behaviour, University of New England (Australia), and Giorgio Vallortigara, of the Centre for Mind/Brain Sciences, University of Trento (Italy).

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Family Feuds: Why Close Relatives Keep Their Distance In The Animal Kingdom

May 30, 2008

Mammals cannot share their habitat with closely related species because the need for the same kind of food and shelter would lead them to compete to the death, according to new research out on May 28, 2008 in Proceedings of the Royal Society B: Biological Sciences.

The team behind the study says this is important because the retreat of natural habitats like rainforests caused by habitat destruction and climate change could inadvertently force closely-related species to live closer together than before.

Lead author of the study Natalie Cooper, a postgraduate student in Imperial College London’s Department of Life Sciences, explains: “Mammal species that share a recent common ancestor have similar needs in terms of food and other resources. Our study shows that this has naturally resulted in closely related species keeping their distance from each other in the wild. Without this separation, one species outcompetes the other.

“The danger is that if mankind’s reduction of natural habitats throws these close relatives together in small geographical areas they could struggle to survive.”

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Mice Mothers Devote Energies To Offspring When Life Is Threatened

May 30, 2008

An Iowa State University researcher has found that sick female deer mice devote their energy to producing healthier offspring.

Lisa Schwanz, a researcher in the department of ecology, evolution and organismal biology, studied the size of offspring for both infected and healthy mice and found that females that had been infected with a parasite produced larger offspring than healthy females.

This finding was unexpected because most mammals tend to focus on their own survival when they are threatened with sickness or infection.

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Pilot Whales Are “Cheetahs of the Sea,” Study Finds

May 23, 2008

Short-finned pilot whales off the Canary Islands race like cheetahs after prey over long distances in the deep Atlantic waters, new research reveals.

Like all whales, pilot whales need to come to the surface to breathe, but they can hold their breaths for extended periods.

Short-finned pilot whales are known to dive to more than 3,200 feet (1,000 meters), but their behavior in the deep ocean has been a mystery.

Researchers monitored the whales near Tenerife, the largest island in the Spanish-controlled archipelago (see map), by attaching tags to 23 of the animals with suction cups.

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Success By Learning: Smallest Predator Recognizes Prey By Its Shape

May 22, 2008

The Etruscan shrew (Suncus etruscus) is one of the world’s smallest mammals. It is about four centimetres long and weighs merely two grams. Being a nocturnal animal, it hunts predominantly with its sense of touch. Professor Michael Brecht (Bernstein Center for Computional Neuroscience, Berlin) now reported on the particularities of its hunting behaviour at the international conference “Development and function of somatosensation and pain” at the Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch, Germany. “As quick as a flash, the Etruscan shrew scans its prey and adapts, when necessary, its hunting strategy,” explained Brecht in his talk. “Thus, no prey escapes.”

The smaller an animal is, the greater is its loss of warmth over its surface. To avoid starvation, the Etruscan shrew has to constantly compensate for this life-threatening energy loss. Thus, it consumes twice its weight every day and feeds on crickets, cockroaches, and spiders. Since the prey are nearly as big as their predator, the shrew has to attack fast and well directed.

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Some dolphins are party animals, some are not

May 19, 2008

Some people are betting at mixing than others, and research shows that dolphins are just the same. Research into bottlenose dolphin behaviour in Cardigan Bay has confirmed that they too have individuals who are social brokers par excellence!  The research provides vital information to help guide the future management of the Bay, which has been designated a Special Area of Conservation in order to give added protection to the dolphins.

Edita Magileviciute, who is Sightings Officer for the Sea Watch Foundation, compared the interactions recorded by the organisation over five years between more than two hundred bottlenose dolphins living in Cardigan Bay in West Wales. On average a bottlenose dolphin has 20 others they associate frequently with during a year – although some can have many more while others have far fewer.

She found that certain dolphins play a key role within their social groups and that one in particular seems to be a constant link between the different social groupings. This dolphin, known as Flint is amongst a number which researchers in the Bay can recognize from its markings recorded as part of an intensive photo ID project which has been running for six years.

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Fur Seal Caught Trying to Mate With Penguin

May 13, 2008

An Antarctic fur seal has been caught on camera trying to have sex with a penguin.

This seems to be the first known example of a sexual escapade between a mammal and another kind of vertebrate such as a bird, reptile or fish, “although some mammals are known to have attempted sexual relief with inanimate — including dead things — objects,” said researcher Nico de Bruyn, a mammal ecologist at the University of Pretoria in South Africa.

One summer morning, scientists observing elephant seals on a beach on Marion Island near the Antarctic spotted a young male Antarctic fur seal subduing a king penguin.

“At first we thought it was hunting the penguin, but then it became clear that his intentions were rather more amorous,” de Bruyn recalled Monday via e-mail.

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Sniffing Dogs Detect Feces To Help Monitor And Protect Threatened Animals In Brazil

May 13, 2008

It’s a tough job, but somebody, or at least some dogs, have to do it.

In the Cerrado region of Brazil, four dogs trained to detect animal feces by scent are helping researchers monitor rare and threatened wildlife such as jaguar, tapir, giant anteater and maned wolf in and around Emas National Park, a protected area with the largest concentration of threatened species in Brazil.

The researchers analyze feces found by the dogs to learn about where and how the threatened mammals live. Data such as numbers, range, diet, hormonal stress, parasites and even genetic identity contribute to a study of how the mammals use environments inside and outside the park, especially on privately owned lands of the region.

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Platypus Genome Explains Animal’s Peculiar Features; Holds Clues To Evolution Of Mammals

May 8, 2008

The duck-billed platypus: part bird, part reptile, part mammal — and the genome to prove it.

An international consortium of scientists, led by Washington University School of Medicine in St. Louis, has decoded the genome of the platypus, showing that the animal’s peculiar mix of features is reflected in its DNA. An analysis of the genome, published today in the journal Nature, can help scientists piece together a more complete picture of the evolution of all mammals, including humans.

The platypus, classified as a mammal because it produces milk and is covered in a coat of fur, also possesses features of reptiles, birds and their common ancestors, along with some curious attributes of its own. One of only two mammals that lays eggs, the platypus also sports a duck-like bill that holds a sophisticated electrosensory system used to forage for food underwater. Males possess hind leg spurs that can deliver pain-inducing venom to its foes competing for a mate or territory during the breeding season.

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New Age of ‘Pocket Pet’ Medicine Begins

May 4, 2008

The American Veterinary Medical Association ( AVMA ) has granted provisional recognition to the first completely new veterinary specialty since 1993. The new specialty will focus on small mammals including rabbits, ferrets, guinea pigs, mice and other small mammals, commonly known as “pocket pets.”

The new Exotic Companion Mammal ( ECM ) specialty was granted provisional recognition by the AVMA Executive Board on April 12, 2008, following recommendation from the AVMA American Board of Veterinary Specialties ( ABVS ) and Council on Education.

“The public and the profession will see these specialists as providing that next level of care of small exotic pets,” explains Dr. Beth Sabin, assistant director of the AVMA’s Education and Research Division. “This new specialty is really the outgrowth of the growing and ever increasing knowledge base of the particular needs of these animals in order to keep them healthy.”

Americans own 6.2 million pet rabbits, 1.2 million hamsters, 1.1 million ferrets, and a million guinea pigs, according to the 2007 AVMA U.S. Pet Ownership & Demographics Sourcebook. The new ECM practice area includes these and other more unusual small pets, including hedgehogs and sugar gliders, but doesn’t include illegal pet species—sometimes referred to as “fad pets”—which have been linked to the spread of zoonotic diseases. In 2003, prairie dogs and Gambian giant pouched rats kept as pets were linked to a serious monkeypox outbreak.

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Roaring Bats: New Scientific Results Show Bats Emitting More Decibels Than A Rock Concert

May 3, 2008

Researchers studying the echolocation behavior in bats have discovered that the diminutive flying mammals emit exceptionally loud sounds — louder than any known animal in air.

Annemarie Surlykke from the Institute of Biology, SDU, Denmark, and her colleague, Elisabeth Kalko, from the University of Ulm, Germany, studied the echolocation behavior in 11 species of insect-eating tropical bats from Panamá, the findings of which are reported in this weeks’ PLoS ONE.

The researchers used microphone arrays and photographic methods to reconstruct flight paths of the bats in the field when these nocturnal hunters find and capture their insect prey in air using their sonar system. Surlykke and Kalko took this information as a base to estimate the emitted sound intensity and found that bats emit exceptionally loud sounds exceeding 140 dB SPL (at 10 cm from the bat’s mouth), which is the highest level reported so far for any animal in air. For comparison, the level at a loud rock concert is 115-120 dB and for humans, the threshold of pain is around 120 dB.

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Legless Lizard And Tiny Woodpecker Among New Species Discovered In Brazil

April 30, 2008

Researchers discovered a legless lizard and a tiny woodpecker along with 12 other suspected new species in Brazil’s Cerrado, one of the world’s 34 biodiversity conservation hotspots.

The Cerrado’s wooded grassland once covered an area half the size of Europe, but is now being converted to cropland and ranchland at twice the rate of the neighboring Amazon rainforest, resulting in the loss of native vegetation and unique species.

An expedition comprising scientists from Conservation International (CI) and Brazilian universities found 14 species believed new to science — eight fish, three reptiles, one amphibian, one mammal, and one bird — in and around the Serra Geral do Tocantins Ecological Station, a 716,000-hectare (1,769,274-acre) protected area that is the Cerrado’s second largest.

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Nature’s great pretenders

April 14, 2008

The firefly, a male Photinus pyralis, winks his best come-on wink as he flies through the summer night: Turning on his light for precisely half a second while swooping upward, he scribes a tiny illuminated “j” in the blackness. Light off, he cruises seven seconds, then—swoop, blink, another “j.” Over and over, he trips his light fantastic in seven-second cadence. On the grass below, an appreciative female answers each “j” three seconds later with a half-second glow, a response that identifies her as a P. pyralis too, and a willing one at that. Encouraged, he draws near and lands next to his newfound mate. The female turns to him, grasps him in her forelegs—and, crushing his body between powerful jaws, devours her would-be lover’s juicy innards.

Such are the dining habits of female Photuris fireflies, a whole different genus. Having cracked the code of the others’ love talk, they lure in tasty Photinus males—and meals—by mimicking the come-hither flashes of Photinus females.

Sneaky? Yes, but hardly unique in nature. Mimicry—the practice of imitating something you’re not to gain some kind of advantage—is widespread. Bugs do it, birds do it, reptiles and amphibians and even mammals do it. It’s a predator-eats-prey world out there, and a little evolved trickery can mean survival.

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Cute animals ‘skewing’ extinction debate

April 2, 2008

Global extinctions are rarer than commonly believed and the extinction debate is too narrowly focused on pin-up images of charismatic birds and mammals, an Australian zoologist says.

Instead Professor Nigel Stork, of the University of Melbourne, urges greater focus on threats facing invertebrates and local extinctions.

Stork says statements about “100 extinctions a day” have become accepted, cited by organisations such as the United Nations and repeated in the popular media.

But Stork believes the science does not back this.

“The truth at the moment is we don’t have enough information to talk about hundreds of species dying out,” says Stork, the head of the university’s School of Resource Management and Geography.

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