Archive for the ‘Zoology’ Category
A female mosquito can not tell if the male has mated which is fertile or otherwise is unable to fertilize their eggs, according to results of recent research.
A precise knowledge of this limitation may help scientists in their mission to prevent the spread of malaria. This knowledge can be the basis for developing strategies to interfere with the reproductive success of mosquitoes. The strategies would induce sterility in high enough numbers of male mosquitoes, and take advantage of the ignorance of the females in this regard.
Malaria is a severe disease that affects more than 300 million people every year, killing nearly 800,000 annually. In Africa a child dies of malaria every 45 seconds. Read the rest of this entry »
The Colugo, the closest living evolutionary relatives of primates, is remarkable for their ability to plan from tree to tree cover considerable distances. When they jump, they display the large membrane spanning the space through his legs and tail, to cover distances of up to 150 meters. They had always believed that these glides were used to move at the lowest possible energy consumption.
New research brings unexpected results at all. The team of Greg Byrnes from the University of California at Berkeley, USA, was followed for six of these amazing mammals in Singapore. To do so, they joined an accelerometer and a radio transmitter device. Analyzing glide paths, the research team realized that Colugo climbed to an altitude of only relatively small to achieve its long gliding at low altitude. Read the rest of this entry »
A new study challenges the validity of previous findings showing that apparently humans are the only primates altruistic. In light of what now discovered, chimpanzees are also able to act altruistically.
The authors of the new research have shown that chimpanzees have a natural inclination toward prosocial behavior. This contradicts the findings of previous studies of chimpanzees described as reluctant to behave altruistically, and led to believe that human altruism emerged as an evolutionary oddity in just the last six million years after humans are evolutionarily separated from apes.
According to the team of Victoria Horner and Frans de Waal, Yerkes National Center for Primate Research, part of the Emory University, U.S., chimps have shown prosocial behavior in other studies due to problems of design of experiments, such as the complexity of the devices used to deliver the rewards to the animals, and distance between each individual. Read the rest of this entry »
The hummingbirds are known mostly for their amazing ability to stay still in the air like a helicopter, but the peak is also a portent of natural engineering.
The shape of the beak of a flying hummingbird of insect trap allows a small fraction of a second, with speed and power higher than could be achieved only by the muscles of the jaw.
The hummingbird’s beak is designed to feed on flowers, but these animals can not survive only on nectar. To get enough protein and nutrients, they also need to eat small insects. Hummingbirds need the equivalent of 300 fruit flies per day to survive.
But how does a long, thin beak is so adapted to suck the nectar that can also be good to catch insects, and often in the air. Read the rest of this entry »
In at least one type of intellectual challenge, some reptiles have recently proved to be as smart as birds and mammals.
In an experiment in which lizards of the species Anolis evermanni, of Puerto Rico, they have been put to test in various cognitive tasks, has been proven that they can learn and remember the solution to a problem that does not have clashed before.
The findings challenge the stereotype scientist reptiles have poor cognitive ability and few strategies for finding food.
The success of the lizards in a test normally used in birds was totally unexpected, even for Manuel Leal’s team at Duke University.
The lizards had the opportunity to feed in a block of wood with two holes, one of which was empty, while the other housed the lizards food (specifically a worm) but was covered by a lid. Read the rest of this entry »
The bright colors of birds have inspired poets and delighted lovers of nature, but the birds themselves are able to see many more colors and hues than humans.
Scientists have speculated for years about how birds evolved their color, but a new study is the first in which they have explored the ability of the birds themselves to see these and other colors.
The birds have cones in their retina that are sensitive to ultraviolet, so they can see colors that are invisible to humans.
The team of Richard Prum of Yale University, and Mary Caswell Stoddard, University of Cambridge, has analyzed the question of why birds have not yet developed the capacity to produce, for example, two distinctly different colors in ultraviolet their feathers, which would be invisible to humans but quite perceptible to birds. Read the rest of this entry »
When humans are depressed or anxious, they tend to see the half empty glass rather than half full. And new research has shown that this phenomenon can be observed in bees.
It is possible to detect evidence of a pessimistic attitude in various animals such as dogs, rats and birds, when they go through difficult times. Now a team of researchers from Newcastle University in the United Kingdom has found through behavioral experiments that bees also share the same behavioral characteristics that indicate a pessimistic attitude.
Researchers Melissa Bateson, Suzanne Desire, Sarah E. Gartside and Geraldine A. Wright has shown that emotional responses of bees to a negative event are more similar than previously thought to those of humans. Bees distressed by the simulated attack by predator pessimism would experience a person in distress in a difficult situation, and present the same basic symptoms in their behavior. In other words, the bees also feel overwhelmed that the bottle is half empty rather than half full. Read the rest of this entry »
Breathing heavily on the edge of a hole in the ice, an Antarctic emperor penguin is prepared to dive. After taking one last breath, the bird is submerged under water and may not emerge until 20 minutes.
The animal begins to sink with the oxygen needed to maintain aerobic metabolism.
This oxygen is stored in three sites: the lungs, blood and myoglobin in the muscles.
However, about 5 minutes and a half after leaving the surface, lactate begins to appear in the blood. And the body of the bird crosses the barrier known as aerobic dive limit, temporarily changing to anaerobic metabolism in some tissues. The key question is: what causes this transition?
It was assumed that penguins crossing the aerobic dive limit when any of its three oxygen tanks emptied. However, it was not clear exactly what mechanism was involved when such a transition.
Paul Ponganis, Scripps Institution of Oceanography, measured levels of oxygen in the blood and lungs of the Penguins after a long dive. And it turned out that the animals had excess oxygen there. That left only the possibility that they were the muscles that activate anaerobic metabolism.
Ponganis, Cassondra Williams and Jessica Meir traveled to Antarctica to measure levels of oxygen in the muscles of emperor penguins during diving. Read the rest of this entry »
Using tracking data from individuals of three shark species, the authors of a new study has found the first evidence that some swim directly to the places they intend to achieve.
The team of marine biologist Yannis Papastamatiou, Division of Ichthyology at the Museum of Natural History of Florida, located on the campus of the University of Florida, has found that tiger sharks and thresher sharks have the ability to aim at great distances.
In the case of tiger sharks, are able to swim to maintain a straight course for at least 6 miles, and resources to achieve specific points located at distances of 50 kilometers. Read the rest of this entry »
American black bears experience a surprisingly large decrease their metabolic rate during hibernation, as has been discovered in a reinvestigation.
The interest in the physiology of animals that hibernate and have a body size similar to that of humans, such as the American black bear, goes beyond the desire to expand knowledge in the field of comparative biology, because the application of the mechanisms of metabolic suppression of bears to people in certain emergency situations can save lives. Since bears are mammals like us, there should be no insurmountable differences between the two metabolisms that would prevent human beings play in a state similar to that available to bears naturally. Read the rest of this entry »