Stingrays often glide across the ocean floor in an effortless, ghost-like manner, but that’s not all they do… right? While the daily movement patterns of sharks are well studied, those of rays remain less understood. A recent study examining the activity of female southern stingrays (Hypanus americanus) in Belize sheds light on when and where these animals are most active. By using accelerometry — a technique that tracks movement — and a statistical approach known as hidden Markov models, researchers classified stingray activity states across different times of the day and environmental conditions. Their findings suggest that these rays are most active at night, with movement patterns influenced more by depth than by temperature.
The southern stingray is a bottom-dwelling ray found in the warm coastal waters of the western Atlantic, ranging from the southeastern United States to Brazil, including the Gulf of Mexico and the Caribbean. Recognizable by its flattened, diamond-shaped body and long, whip-like tail, this species is primarily benthic. Spending much of their time buried in sand or mud, they use electroreceptors to detect buried prey such as crustaceans, mollusks, and small fish. They are non-aggressive but equipped with a venomous spine on their tail for defense against predators, like sharks. These rays play an important role in their ecosystems by stirring up sediment and influencing prey populations. While not currently considered threatened, habitat degradation and overfishing pose risks to their populations, making continued research and conservation efforts essential.
Nine stingrays were tagged and monitored, allowing researchers to assess three different levels of activity: low, medium, and high. Overall, the predators were most likely to enter a high-activity state at night, while their movement slowed in the morning. However, there was some individual variation, suggesting that while diel (day-night) patterns play a key role in their activity, stingrays don’t all behave exactly the same way. Interestingly, regardless of whether they were moving a little or a lot, the stingrays consistently used shallow waters — less than 13 feet (4 meters) — during their most active periods. The researchers believe that this suggests that depth, rather than time of day, may be a strong driver of their behavior.
Temperature, on the other hand, had little influence. While three individuals showed heightened activity in cooler water, this wasn’t a consistent trend across all the stingrays studied. Instead, diel cycles and depth appeared to be the main factors shaping their movement patterns. This aligns with what we already know about many other elasmobranchs (the group that includes sharks, skates, and rays), which tend to show crepuscular (dawn and dusk) or nocturnal activity. Nighttime movement may help stingrays avoid predators, improve their hunting efficiency, or take advantage of environmental conditions that make traveling easier.
While these findings provide a clearer picture of this specie’s behavior, there’s still much to learn. The study only involved nine individuals, meaning a larger sample size could provide even stronger insights. Future research could also extend the length of time stingrays are monitored, helping to capture a more complete view of their daily and seasonal movements. And the team say another key question that needs to be answered is how predator-prey interactions shape stingray activity — whether they are more active at night to hunt or to evade predators, which currently remains unclear.
Understanding when and where stingrays move is important for conservation and management efforts, particularly in areas like Belize, where marine tourism and coastal development can impact their habitats. By identifying their peak activity periods and preferred depths, scientists and policymakers can make more informed decisions about protecting these animals and the environments they rely on. As technology advances and more long-term tracking studies are conducted, scientists will continue to uncover the hidden rhythms that drive stingray behavior beneath the waves.