Are Shark Attacks Related To Lunar Phases? Possibly, Says Research.

Chances are if you share a home with a space-loving person that you already know that 2022 has had its first full moon. The January full moon, also known as the full Wolf Moon, occured when the moon is when the Moon is on the opposite side of Earth from the Sun, fully illuminated. It’s not just pretty to look at – it can also change the way some animals behave when it’s out.

No, this isn’t about werewolves. The behavior of many animal species has been scientifically linked to phases of the moon (such as seabirds, amphibians, mammals, and many marine animals like giant manta rays or gray reef sharks). Sharks have well-documented lunar-associated rhythms in their movements, catch rates, and natural feeding patterns. But another shark behavior that might be influenced by when the moon decides to make its presence really known is the frequency of shark bites.

Few studies have looked at any possible connection between the phase our moon is in and shark bites on humans, with the few results published having been preliminary or lacking any kind of relationships. Yet, new research from Louisiana State University (LSU) and the University of Florida (UF) suggests that more shark bites occur during fuller phases of the moon, with the data coming from the global International Shark Attack File. “We wanted to answer the question of whether shark attacks were more or less frequent during different phases of the moon (as represented by lunar illumination),” the authors state in the new study. “We sought to evaluate this possible relationship by considering geography of the attacks, reported species involved in the attack, and the outcome of the attack in terms of fatality.”

Researchers found a clear correlation between lunar phases and shark cites, with more shark attacks than average occurring during periods of higher lunar illumination and fewer attacks than average occurring during periods of lower illumination. And while the team say it is still too early to demonstrate that lunar illumination is a causative factor for shark bites, the “abundance of data we have would suggest that there is something there that’s worth continuing to look at,” Steve Midway, LSU associate professor and researcher on the project said. “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.”

But this isn’t something seen in all sharks. “Interestingly, species-specific analysis showed the fewest instances of significant moon phases (only one significant effect for white sharks). This was somewhat surprising because moon effects in other marine animals are often reported to be species-specific, and as such it would not have surprised us to see different patterns of effects in different shark species,” the authors said, going on to explain that what may likely be going on is that different local effects could be adding variability to any overall species effect.

“The relationship we have reported here may not be causative, and as such we are not necessarily recommending that there are any immediate risk management benefits to our findings,” the authors caution, stating that moon phase and lunar illumination will not likely be a strong predictor that alone can forecast risk of shark bites in an area.  “Rather, we hope to underscore the complex nature of shark attacks that not only involves sharks and humans, but the wider environment.”