U-Shaped Link Between Animals Diet and Body Size Discovered, Associating It With Humans

It has been decades since researchers noticed the U-shaped relationship between diet and body size seen in modern land mammals.

As indicated in a Cosmos report, if one aligns mammals on a plant-to-protein gradient, he'll find that herbivores and carnivores are inclined to be much larger than insectivores and omnivores.

Now, it's known that such a link is more widespread compared to previously thought. Based on the new research, it is rather almost universal across 24.000 vertebrate species, which include mammals, reptiles, saltwater fish, and birds.

The pattern holds consistency as well, across worldwide ecosystems, chrome rainforests to deserts, and even dates back to approximately 66 million years back.

Human-Related Extinction Disrupting the U-Curve

Researchers have suggested though, that human-related extinction of the largest herbivores and carnivores is disrupting such a U-curve, What's appearing to be an important feature of both past and present ecosystems with potentially unexpected results for the future.

Essentially, a species' diet specifies the amount of energy it's consuming, which in turn, is helping drive growth, not to mention, dictates its size.

However, that particular size can limit the quantity too, as well as the quantity of food available to the species, even as it simultaneously sets thresholds for what is needed to survive.

According to Will Gearty, a postdoctoral researcher at the University of Nebraska-Lincoln in the United States, and co-author of the study published in Nature Ecology & Evolution, one can be as big as its food it is allowed to be. Therefore, he elaborated, there is an "evolutionary interplay here."

U-Shape Pattern Between Body Size and Diet for Almost All Animals

The international and interdisciplinary research team collected diet and body size data for an exceptional number of modern surviving species, more than 5,000 mammals, over 8,900 birds, 7,300 reptiles, and 2,700 fishes.

For the first time, the researchers discovered that the U-shape pattern between body size and diet held for nearly all animal species, although was not present in marine mammals and seabirds, perhaps because of the unique demands of living in the water.

The U-shaped link between diet and body size has prevailed, so they evaluated fossil records from over 5,400 mammal species, some of which dated as far back as the Early Cretaceous Period about "145-100 million years ago," and discovered that the pattern stretches back at least 66 million years, a similar United Press International report specified.

However, the U-curve has started to evidently flatten, as the average size of mammalian herbivores has dropped by roughly 100 times, and carnivores by 10 times, since the occurrence of the Netherlands and Homo sapiens over the past few hundred thousand years.

This is because of the multiple extinction of species, which include the vanishing of mammoths, short-faced bears, ground sloths, and saber-toothed cats.

Side Effects on the Environment and Ecosystem

Looking to the future, the researchers project that there is a greater than 50-percent chance that multiple large- and medium-sized mammals, including the digger and Javan rhinoceros, both of which consider humans as their lone predators, will go extinct within the next two centuries.

This does not bode well, as those forecasted extinctions would only exacerbate the disturbance of the U-curve and have unpredictable consequences for both humans and wildlife.

Gearty said it is certainly plausible "that as we take some of these animals off the U-curve's top" and as some of these ranges of body sizes are collapsed that the way the energy is divvied up is altered,

He added that could probably have fundamental repercussions for the environment and ecosystem in general.

Related information about animal diet is shown on North Carolina Zoo's YouTube video below:

Check out more news and information on Animals in Science Times.