This Bouncing African Mammal Glows Under UV Light

Springhares are the latest in a flurry of furry creatures that scientists have discovered are biofluorescent

glowing springhare
New research finds that springhares, hopping rodents native to southern Africa, glow under UV light. J. Martin and E. Olson, Northland College; from Olson et al. 2021, Scientific Reports

Scientists have discovered that a seven-pound African mammal called a springhare has fur that glows in shades of red and pink under ultraviolet light, reports Cara Giaimo for the New York Times.

The nocturnal, burrow-dwelling springhare is the latest addition to a growing list of biofluorescent furry critters that includes platypuses, flying squirrels, and potentially even Tasmanian devils, echidnas and wombats.

Body markings that absorb light in the ultraviolet spectrum—the type of otherworldly glow emitted by black lights—become visible to animals like us when light reflects back at a lower energy level, which causes it to change colors. It’s a trait more common in fish, amphibians and birds, reports George Dvorsky for Gizmodo.

Finding biofluorescence in several species of mammals, where it was thought to be rare, suggests the trait “may be more broadly distributed than previously thought,” write the authors of the study documenting the findings last week in the journal Scientific Reports.

But the researchers can’t be sure if the UV glow has a purpose for the springhares or if it’s just an evolutionary accident.

This Bouncing African Mammal Glows Under UV Light
Biofluorescence in a captive springhare photographed for the study. The photos featuring no visible glow were taken under normal lighting conditions. J. Martin and E. Olson, Northland College; from Olson et al. 2021, Scientific Reports

"We speculate that, if their predators are UV sensitive–the unique patterning we observed could function as a sort of camouflage from predators," Erik Olson, a biologist at Northland College and the study’s lead author, tells Tom Hale of IFLScience. "However, there is a chance that this trait has no ecological significance what-so-ever. It is purely speculation, and until there are behavioral studies and studies assessing the spectral sensitivity of springhare and their predators it will be hard to confirm."

Olson and his colleagues came upon the springhare’s UV glow while shining a black light at the contents of drawer after drawer of preserved mammal remains in the natural history collection of the Field Museum in Chicago. For the study, the team examined 14 springhares that all showed biofluorescence, according to the Times.

The team’s investigation into biofluorescence in mammals got started several years ago when one of the paper’s authors turned a UV flashlight on a flying squirrel in his backyard. Since then, the group has been searching high and low for fur that glows under UV light.

When Olson and his co-authors conducted a chemical analysis of springhare hair, the researchers found that pigments called porphyrins were primarily responsible for the creature’s biofluorescence.

Speaking with IFLScience, Olson notes that the presence of these porphyrins could also be a byproduct of disease. "In humans, overproduction of porphyrins is characteristic of a disease called porphyria,” he says. “Springhares could be depositing or storing excess porphyrins in their fur that might otherwise cause disease. If that is true, then springhares could potentially help us better understand the disease porphyria."

Ultimately, the current members of the UV biofluorescent mammal club don’t point to any clear explanation or functional basis for their respective owners’ glowing fur, Tim Caro, a evolutionary biologist at the University of Bristol who was not involved in the research, tells the Times. “There is no pattern,” he says. “Either we don’t know the function of this sort of coloration, or there is no function at all.”

In the meantime, Olson and his colleagues are going to continue searching for biofluorescent mammals in hopes of better characterizing its prevalence and perhaps illuminating its purpose.