In a startling discovery, scientists have documented the first-ever case of a large, predatory porbeagle shark being eaten by an even bigger shark. This unexpected event occurred near Bermuda, and researchers believe the predator was likely either a great white shark or a shortfin mako.
Porbeagle sharks, known for their muscular, streamlined bodies and sharp, spear-like teeth, are formidable predators themselves. They can grow up to 12 feet long and patrol the Northern Atlantic as well as parts of the Southern Hemisphere, even venturing into the Antarctic. However, this incident reveals that even these powerful creatures are not immune to predation.
The unfortunate porbeagle shark, a pregnant female, was tagged in October 2020 with both a satellite transmitter and a pop-off satellite archival tag (PSAT) near Cape Cod. These devices were intended to track the shark’s movements and depths over time. The PSAT tag, designed to detach after a year, recorded data on the shark’s depth using pressure and temperature readings.
The shark’s movements showed a consistent pattern, ranging between the surface and 328 feet deep until December 2020. From that point on, the shark began diving to depths of up to 2,600 feet during the day and hovering around 650 feet at night as it moved south towards Bermuda.
On March 24, 2021, the data from the PSAT tag underwent a drastic change. The temperature readings, which had previously been consistent with the shark’s depth, suddenly started recording temperatures much warmer than expected. This change, according to the researchers, indicated that the tag was now inside the stomach of another shark.
The researchers concluded that the predator was most likely either a great white shark or a shortfin mako, both of which are known to inhabit the area and are large enough to consume a porbeagle. The white shark appears to be a more likely candidate, as the tag’s depth range remained relatively stable after ingestion, while makos are known for their deep dives and rapid ascents.
This remarkable discovery highlights the complex and sometimes unexpected interactions within the ocean’s ecosystem. It also reinforces the vulnerability of porbeagle sharks, a species already under threat from overfishing and listed as vulnerable by the IUCN. The predation of this pregnant female porbeagle is a reminder that even apex predators are part of a larger food web, and their fate is interconnected with other species within their environment. This event underscores the need for continued research to understand the delicate balance of life in the oceans.
