Just like werewolves and people who are way too into astrology, lunar cycles may have a curious hold on sharks – new research has suggested that shark attacks occur more frequently during fuller phases of the moon.
In the journal Frontiers in Marine Science, scientists from Louisiana State University and the University of Florida sifted through 55 years of data on shark attacks from the Florida Museum of Natural History’s International Shark Attack File. This revealed a clear correlation between shark attacks and the moon’s phases, with more shark attacks occurring during periods of higher lunar illumination and fewer attacks during periods of lower illumination.
The reason for this curious observation, however, is uncertain. You may assume it has something to do with the moonlight illuminating the sea, making prey more visible – but the researchers suspect that other factors are at play.
Two likely candidates are the gravitational influence of the moon on the ocean's tides, and perhaps even its effect on electromagnetic fields that sharks and many other creatures use to navigate.
“It’s not a matter of more light at night for sharks to see. Most shark attacks occur in the daylight. However, the moon can exert other forces on Earth and its oceans in ways that are much more subtle – for example, the gravitation pull that we see affect the tides,” Steve Midway, study author and associate professor of oceanography at Louisiana State University, said in a statement.
Although they admit that the relationship between moon phases and shark attacks may not be causative at all – another factor can explain the link or maybe it’s just coincidence – they believe the link is strong enough to warrant further investigation.
“The abundance of data we have would suggest that there is something there that’s worth continuing to look at,” added Midway.
Don’t forget that shark attacks are exceptionally rare – the International Shark Attack File reported and confirmed 57 unprovoked shark attacks and 39 provoked attacks throughout the world in 2020. There were 13 shark-related fatalities in that year, but they usually see just four unprovoked fatalities per year globally each year. They also point out that you're 100 times more likely to get bitten by a human in New York City than bitten by a shark in the US.
Conversely, human attacks on sharks are unbelievably common. Research has indicated that humans are responsible for the deaths of approximately 100 million sharks each year. Somebody needs to get sharks a better PR team.