14 DAY TRIAL // Canadian researchers from the University of Toronto Scarborough determined in a new study that the special metabolism of hummingbirds allows these diminutive species to burn both glucose and fructose just as efficiently inside their bodies. They are the only vertebrate creatures capable of doing this.
Scientists say that this is basically the optimal fuel-use strategy for a creature as active and metabolically-intensive as the hummingbird. They take their sugars from the nectar of plants, just like other birds and insects, but do not exhibit a preference towards a type of sugar or another.
Usually, vertebrates burn glucose efficiently as a primary energy source. When no more glucose is available, animals, including humans, can switch to fructose, but the downside is decreased conversion efficiency and reduced energy, e! Science News reports. This does not happen in hummingbirds.
“What's very surprising is that unlike mammals such as humans, who can't rely on fructose to power much of their exercise metabolism, hummingbirds use it very well. In fact, they are very happy using it and can use it just as well as glucose,” explains UTSC Assistant Professor of Biological Sciences Kenneth Welch, who is a renowned expert on the diminutive birds.
The work is detailed in the latest online issue of the scientific journal Functional Ecology, and it is scheduled to appear in a future print edition as well.