These causes of death often exert opposite pressures on animals, for example, storing lots of fat helps animals survive periods without food but also slows their running and so makes getting caught by a predator more likely. Animals can be stronger to compensate, but the energetic costs of extra muscle mean that the animal would starve quicker during a food shortage.
Led by Dr Andrew Higginson of Bristol's School of Biological Sciences, the researchers used mathematical models to explore how much muscle and fat animals should have in their body to give themselves the best chance of survival. They showed that an important consideration was how much carrying fat increases the energetic costs of movement. The models revealed that the size of this cost influenced whether larger animals should have more fat than smaller animals, or vice versa.
Dr Higginson said: "Our results explain differences between different families of mammal. For example, larger bats carry proportionally less fat than small bats but larger carnivores carry more fat than small carnivores. Among rodents, it's the medium-sized species that carry around the most fat! These differences agree with the models predictions if you consider the costs of carrying fat for these three groups. Bats fly and so have high costs of carrying extra weight, whilst carnivores spend much of their time resting and so will use less energy than busy scurrying rodents."
The work, published in The American Naturalist, also shows that much of the variation between animals in their amounts of fat and muscle can be explained by differences between the sexes, how much animals have to fight to get food, and the climate in which they live.
The researchers plan to put the theory to the test by looking in more detail at the amounts of fat stored by different animals. If their theory is correct, much of the mystery in how species and sexes differ in their amount of fat will have been solved.
Hannah Johnson | EurekAlert!
Mass spectrometry sheds new light on thallium poisoning cold case
14.12.2018 | University of Maryland
Protein involved in nematode stress response identified
14.12.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy