Trail Camera Captures Moths Drinking Moose Tears, Marking Major Scientific Finding

Nature finds a way…to quench its thirst.

For the first time ever, scientists reviewing trail camera images from Vermont have documented moths drinking tears directly from a moose’s eyes. The discovery represents the first time this behavior, known as lachryphagy, has been observed on moose anywhere in the world and marks only the second record of tear-feeding moths outside tropical regions in more than 50 years.

A bull moose stood in Vermont’s Green Mountain National Forest just before 2 a.m. on a June night in 2024, seemingly oblivious to the moths fluttering around his face. Over four minutes, trail cameras captured 80 images showing at least one moth positioned at the moose’s eyes in every frame where the eyes were visible, with additional moths flying around and repeatedly visiting. The moths’ heads appeared pressed against the area surrounding the eye, and their persistent visits made lachryphagy the most plausible explanation.

Researchers from the Vermont Cooperative Fish and Wildlife Research Unit weren’t looking for tear-drinking moths when they placed cameras throughout the state’s forests as part of an ongoing wildlife survey. When biologist Laurence Clarfeld reviewed more than 247,000 images of moose collected from 476 sites across Maine, Massachusetts, New Hampshire, and Vermont, this single sequence stood out. Outside the tropics, where most reports come from Africa and Asia with some from the Neotropics, scientists had recorded only one previous instance in the United States: a moth spotted at a horse’s eyes in Arkansas back in 1972.

Why Moths Drink Tears from Animal Eyes

Tear-drinking, while unusual, has long been documented in tropical regions where moths visit the eyes of everything from elephants to reptiles. The behavior appears linked to obtaining essential nutrients that flower nectar alone cannot provide. Moths need sodium, proteins, and other minerals to survive, leading many species to engage in “puddling” at muddy spots, animal waste, or even human sweat. Tear-feeding takes this strategy further, with moths feeding directly from the eyes of living animals.

In tropical Africa and Asia where most tear-drinking has been documented, the behavior concentrates in areas with hot, dry seasons when flowers producing nectar become scarce. Moths in these regions have been observed visiting the eyes of domesticated cattle, horses, water buffalo, and mules, as well as wild elephants and several deer species kept in captivity. Some exclusively lachryphagous moth species in Asia have even evolved the ability to digest proteins from tears.

Moose represents a newly documented host species for lachryphagy and one of the few instances documented in a mammal outside of captivity. One of Vermont’s moth experts examined the trail camera images with colleagues and reached a consensus that the moths most likely belong to the Geometridae family based on their size and shape, though image quality makes precise identification difficult. The moth species observed at a horse’s eyes in Arkansas in 1972, Euchlaena pectinaria, has not been found in Vermont or elsewhere in New England, so this almost certainly involves a different species.

Tear-Drinking Moths in Temperate Climates

The reasons moths in Vermont forests would adopt this behavior remain unclear, but patterns in tropical moths offer clues. Between 1:44 and 1:48 a.m., the camera snapped images showing moths positioned just below one or both of the moose’s eyes. Two or more additional moths flew around the moose, visiting the eyes multiple times during those four minutes. The positioning and repeated visits to the eye area made lachryphagy the most plausible explanation.

Moth species in temperate regions like Vermont tend to favor sodium above other nutrients when puddling, unlike their tropical counterparts that may seek proteins. The moths visiting the Vermont moose might be obtaining sodium during a time when other sources are unavailable. Vermont’s temperate climate, with cold winters and humid summers, doesn’t match the tropical patterns where tear-drinking concentrates in areas with pronounced dry seasons.

The single documented instance from reviewing nearly a quarter million moose images suggests tear-drinking remains rare in New England, though no other sightings have been reported despite extensive wildlife camera networks across the region.

Health Effects on Moose Populations

Biologists wonder if the behavior could affect moose health. Moths visiting eyes might potentially spread diseases like keratoconjunctivitis, an inflammation that can cause eye lesions in moose. However, moths have not yet been documented transmitting pathogens during tear-feeding, leaving this possibility unproven.

Any potential disease transmission could add to the already heavy burden moose in the eastern United States face from parasites. Winter ticks infest moose in massive numbers, creating heavy infestations. Moose are more likely to succumb to tick infestations when fighting other parasites like meningeal worm.

The observation, now published in an Ecosphere paper, opens new questions about tear-drinking behavior in tropical versus temperate climates, what ecological role this feeding strategy plays in northern forests, and how it might affect both moths and moose. Studying wild animal behavior at night in dense forests presents challenges, and the behavior might be more common than records suggest simply because it’s difficult to observe.

Scientists reviewing wildlife camera images from New England forests now have reason to watch more carefully for moths near animals’ eyes. What seemed like an exclusively tropical phenomenon has proven to occur in at least one temperate forest.

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