Compared to Tiny Animals, Huge Animals Consume Less Food and Expend Less Energy

For ages, researchers have pondered the mystery of why, kilo for kilo, larger animals consume less food and expend less energy than smaller ones.

Why can a gigantic baleen whale survive on a daily diet of just 5 to 30% of its body weight in krill but a little shrew requires up to three times its body weight in food?

Why Do Larger Creatures Use Less Energy?

(Photo : David Heiling/Unsplash)

Previous attempts to explain this link depended on physics and geometry, but scientists think that evolution is perhaps the best explanation, as per Phys.org

The best way to optimize an animal's capacity to procreate is through this interaction.

Nearly 200 years ago, the first theory explaining the unequal link between metabolism and size was put forth.

The rules of physics cannot be disregarded by living things.

However, evolution has shown to be incredibly adept at figuring out how to get beyond geometric and physical limitations.

In this recent study, researchers chose to disregard such physical and geometrical restrictions to investigate what would happen to the link between metabolic rate and size.

Therefore, they created a mathematical model to describe how animals consume energy throughout their lives.

In their scenario, animals first invest energy in growth early in life before investing ever more energy in reproduction as they get older.

Since reproduction is the major goal of evolution, researchers utilized the model to identify the traits of animals that lead to the most offspring throughout their lifetimes.

They discovered that the creatures that display the exact type of disproportionate scaling of metabolism with a size that scientists witness in nature are the ones that are projected to be the most effective at reproducing.

This finding implies that unequal metabolic scaling is not a natural outcome of geometric or physical limitations.

This scaling is instead a result of natural selection because it is favorable for lifetime reproduction.

Less frequently than formerly believed, physical limitations may be the primary causes of biological patterns.

People don't fully grasp the range of options open to evolution.

Physics Does Not Define Life; Biology Does

According to the another article of Phys.org, the researchers' mathematical model of animal growth, which depicts how animals focus their energy on growth and reproduction as they get older and bigger, is presented in a study that was just published in Science

According to lead study author Professor Craig White of the Monash University School of Biological Sciences and the Center for Geometric Biology, evolution has demonstrated a remarkable talent for spotting weaknesses.

Living organisms cannot break the laws of physics, but evolution has shown itself to be extraordinarily adept at finding loopholes.

The non-proportional (allometric) link between energy metabolism and size is a mystery in biology.

During growth or evolution, a gain in size is often followed by a less-than-proportional rise in energy needs, so that, gram-for-gram, larger creatures consume less food and expend less energy than smaller ones.

Professor White's team developed a mathematical model of animal growth that shows that lifetime reproduction is maximized when metabolism grows out of proportion with size.

As animals get older and bigger, they change their energy allocation from growth to reproduction.

Since the early nineteenth century, numerous models have been put forth to explain this pattern, but Professor White's team does not.

To put it simply, while traditional theories claimed that animals have the metabolisms they have because they must, researchers discover that they do so because it is the best.

According to Professor White, the work demonstrated that allometric scaling need not be caused by geometric or physical constraints.

Instead, allometric scaling is supported by natural selection rather than physics.