Animals living near colder climates are bigger in size because being heftier allows them several benefits like reducing body heat loss, researchers said. For most species of vertebrates, body mass increases the closer you get to the poles. The bigger you are, the more fat you can store to help you get through the winter. The average weight of an adult male white-tailed deer in Florida, for instance, is about 57 kilogrammes, while a mature buck in Montana might weigh 114-125 kg, the 'Live Science' reported. For many types of animals, it pays to be bigger in the colder climates that exist at high latitudes and altitudes. Heftier animals have a smaller surface area-to-volume ratio, which helps reduce heat loss - a pattern known as Bergmann's Rule. In general, a more massive organism has a smaller surface area-to-volume. According to Kyle Ashton, herpetologist at the California Academy of Sciences in Golden Gate State Park in San Francisco, there are several factors that can affect an animal's body size and weight. An abundant food supply, sexual selection for bigger males and encounters with competitors may all lead to bigger bodies. While Bergmann's Rule explains how animals deal with issues of heat loss and heat regulation in the cold, there may be other reasons to pack more pounds in colder climates. "The bigger you are, the more fat you can store to help you get through the winter," said Ashton. More nutritious foods may also fuel bigger body size closer to the poles, according to researchers from the University of Houston. Plants from higher latitudes tend to be softer and contain more nutrients than plants closer to the equator, they found. While the pattern of bigger bodies in colder climates holds for most mammals, birds and some reptiles, such as turtles, lizards and snakes, seem to break the mould. "They reverse the rule and tend to be smaller in colder climates and bigger in warmer ones," said Ashton. The verdict is still out on why some reptiles, which obtain their body heat from the external environment, follow the rule while others reverse it. Ashton suspects it may be advantageous for turtles, which may go several months without eating in colder climates, to carry extra fat stores, the report said. For lizards and snakes, some scientists think smaller bodies may warm faster in cold temperatures. Source: Indian Express
Why animals are bigger in colder climates decoded
Animals living near colder climates are bigger in size because being heftier allows them several benefits like reducing body heat loss, researchers said. For most species of vertebrates, body mass increases the closer you get to the poles. The bigger you are, the more fat you can store to help you get through the winter. The average weight of an adult male white-tailed deer in Florida, for instance, is about 57 kilogrammes, while a mature buck in Montana might weigh 114-125 kg, the 'Live Science' reported. For many types of animals, it pays to be bigger in the colder climates that exist at high latitudes and altitudes. Heftier animals have a smaller surface area-to-volume ratio, which helps reduce heat loss - a pattern known as Bergmann's Rule. In general, a more massive organism has a smaller surface area-to-volume. According to Kyle Ashton, herpetologist at the California Academy of Sciences in Golden Gate State Park in San Francisco, there are several factors that can affect an animal's body size and weight. An abundant food supply, sexual selection for bigger males and encounters with competitors may all lead to bigger bodies. While Bergmann's Rule explains how animals deal with issues of heat loss and heat regulation in the cold, there may be other reasons to pack more pounds in colder climates. "The bigger you are, the more fat you can store to help you get through the winter," said Ashton. More nutritious foods may also fuel bigger body size closer to the poles, according to researchers from the University of Houston. Plants from higher latitudes tend to be softer and contain more nutrients than plants closer to the equator, they found. While the pattern of bigger bodies in colder climates holds for most mammals, birds and some reptiles, such as turtles, lizards and snakes, seem to break the mould. "They reverse the rule and tend to be smaller in colder climates and bigger in warmer ones," said Ashton. The verdict is still out on why some reptiles, which obtain their body heat from the external environment, follow the rule while others reverse it. Ashton suspects it may be advantageous for turtles, which may go several months without eating in colder climates, to carry extra fat stores, the report said. For lizards and snakes, some scientists think smaller bodies may warm faster in cold temperatures. Source: Indian Express
Is it possible to live on Mars?
Perhaps, people could live on Mars. The radiation levels on the planet are as low as in the lower earth orbit where the International Space Station flies. Scientists have arrived at this conclusion after receiving radiation measurement results from the red planet. Nevertheless, experts are not in a hurry to review their approaches towards the protection of people when making preparations for future expeditions to the Mars.
Radiation remains to be the major obstacle in carrying out manned flights to Mars. This has been technically expedient since the early 1970s. However, scientists have not developed light materials to protect people from radiation yet, while it’s impossible to take heavy thick lead plates into space. It has been estimated that during the three-year flight one of every four crew members might receive a dose of radiation enough to trigger a fatal cancer disease. These three years include the waiting time for favourable conditions to start the return journey. If radiation has no effect on the crew during this period of time, there is a need to make new assessments, says biologist at Moscow State University, Elena Vorobeova. “Any new information will change our apprehension, and as a result, we will review our approaches towards assuring safety for cosmonauts. However, I believe that overall, this will not affect our general understanding of how to protect cosmonauts on Mars,” Elena Vorobeova said. During the flight, there is nowhere to hide from dangerous cosmic radiation. Moreover, there is no magnetic field around the planet like on Earth that protects living beings from solar flares. Here is an opinion from head of the department at the Institute of Medical and Biological Problems Vladislav Petrov. “I see no reason to review any principles or approaches. The atmosphere on Mars is a sufficient protection from various kinds of comic radiation. However, during strong solar flares, the dose of radiation could be large, and this may cause problems. These problems are quite different from those when we fly around the Earth. One of them is the deterioration of working efficiency under the influence of radiation. We are aware of this even when driving a car. We hope that such a thing never happens during a flight to Mars,” Vladislav Petrov said. The influence of radiation during a stay on Mars is comparable to that during an orbital flight. In fact, a stay on board the ISS for months is also not so safe because cosmonauts are affected by heavy cosmic particles that cause various kinds of defects in the eyes. There have been incidents of growing cataract, says Vladislav Petrov. The issue should be thoroughly studied not only on the basis of what has been observed in cosmonauts but also on the basis of special experiments. Russia is planning to conduct these experiments on board the BION satellite next year,” Vladislav Petrov added. Concerning the chances for discovering life on the Mars, the new information sent by Curiosity Mars rover will have no effect on it since radiation is not the most harmful thing for a living cell. Sometimes bacteria live in the closest proximity to nuclear reactors where radiation is extremely high. Scientists assess the living condition on Mars as not very extreme. Vladislav Petrov believes that new information will lead to the review of the evolution of the biosphere on the planet. However, the search for the constituency of the biosphere on Mars has not ended successfully. If there is no evidence of life on Mars there is no need to review any hypothesis of its development. Still, there is no clear answer to the main question. Scientists cannot answer why Mars has entirely lost its atmosphere and water, and its warm and wet climate has been replaced by cold and dry weather. Source: Voice of Russia
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