Researchers at the Stowers Institute for Medical Research in Kansas have uncovered a striking trait in bats: they tolerate blood glucose levels that would be lethal for other mammals, including humans. The work appears in Nature Ecology and Evolution.
The researchers describe this finding as the highest natural blood glucose levels ever recorded in a mammal group. In mammals, such extreme sugar levels typically trigger coma and fatal outcomes, yet bats seem to thrive under these conditions. This discovery opens new questions about how enzymes, tissues, and signaling pathways in bats cope with sugar overload without suffering the same damage seen in other species.
Dating back about thirty million years, Neotropical leaf-nosed bats began their lineage as insect eaters. Over time, these bats diversified into a wide array of species with diets that span insects, fruit, nectar, meat, and even blood. This dietary breadth offers a natural laboratory for studying how different feeding strategies influence metabolism and sugar handling in bats.
To understand how these animals have diversified their diets, scientists conducted fieldwork across the forests of Central America, South America, and the Caribbean. In total, nearly 200 wild-caught individuals from 29 species underwent glucose tolerance testing to map how each species processes a sugar load. The field observations and laboratory data together illuminate how natural environments shape metabolic traits in these mammals.
The research highlights a concept known as glucose homeostasis, the body’s tight regulation of blood sugar. In most mammals this balance rests on insulin and related hormonal signals, but bats show a mosaic of adaptations. Some species exhibit changes in gut anatomy that influence nutrient absorption, while others carry genetic variations in sugar transport proteins that shuttle glucose from blood into cells more efficiently or differently than in other mammals. These mechanisms together create a spectrum of strategies to maintain steady blood sugar even when diet fluctuates dramatically.
Among the findings, certain nectar-feeding bats show stable expression of a gene that governs sugar transport, a pattern also observed in hummingbirds. This parallel hints at convergent evolutionary solutions to managing high sugar intake from nectar and similar dietary sources. The consistent gene expression related to glucose transport in these bats suggests a molecular basis for their unusual sugar tolerance that researchers are eager to explore further.
The implications extend beyond basic science. By better understanding how bats control blood sugar without adverse effects, scientists aim to identify new targets and approaches for treating diabetes and other metabolic disorders in humans. The work underscores how studying diverse species can reveal biological principles with real-world medical relevance. While these findings are still early, they point to a promising avenue for translating natural adaptations into therapeutic strategies.
Throughout the study, researchers maintained a careful, multidisciplinary approach that combines field ecology, physiology, and molecular biology. By examining both the ecological contexts in which these bats live and the cellular mechanisms that govern sugar handling, the team builds a more comprehensive picture of how metabolism can be optimized in living systems. The ongoing work continues to chart how different dietary pressures shape the evolution of metabolic pathways in bats and what that means for human health.
Remarkably, this line of inquiry also invites broader questions about animal intelligence and problem solving. While the current research emphasizes metabolic resilience, other studies have noted sophisticated cognitive abilities in bats, suggesting that their ecological roles may depend on a suite of adaptive traits beyond sugar processing. The new findings about glucose regulation add another dimension to our understanding of bat biology and the remarkable ways these creatures navigate their diverse diets and environments.