A study published on October 28 in the Journal of Experimental Biology by an international team of scientists studying whales off the coast of Palos Verde and San Diego, California, reported the first-ever continuous recording of a remora hitchhiking on a baleen whale.
Remoras are also known as suckerfish as they use super-powered suction disks on their heads to stick on the bodies of larger marine life, such as sharks and whales.
The video recording helped the researchers uncover the remora's secret surfing life beneath the ocean they used to navigate the intense hydrodynamics aboard a 100-feet blue whale.
Whales As a Floating Island For Remora
The study reveals how the remora was able to hitchhike on a whale that is more than 30 times its size and safely traverse the ocean, Phys.org reported. The remora chose the most optimal location of the whale's body to stick to where the drag resistance for it is reduced as much as 84%.
Additionally, they also found that the remoras can still feed and socialize even while being attached to the whale and even if the whale speeds up its pace of up to five meters per second by using unknown surfing and skimming strategy.
The recording captured by the researchers is the highest-resolution whole-body fluid dynamic analysis of whales to date. It could be used to understand the behavior, energy use, and overall ecological health of whales and improve tagging and tracking of other migratory animals.
Biology assistant professor Brooke Flammang at New Jersey Institute of Technology and study the corresponding author said that whales had become the remora's own floating island as if it was their own little ecosystem.
It was a fortunate coincidence that they were able to capture how remoras interact in this environment and utilize the whales' flow dynamics to their advantage. Science knows next to nothing how remoras behave in their hosts.
The 211-minute video captured a total of 27 remoras at 61 locations on the whales, which tells that the remoras are most often found plodding and traveling between the most hydrodynamically beneficial spots of the whale: behind the blowhole, next and behind the dorsal fin, and the pectoral fin's flank region that is above and behind it.
The video showed how strong the remoras' suction ducts are that gives them a smooth ride while hitchhiking on a whale, saving them energy and making life less costly.
Remoras Surf Within The Whale's Thin Layer of Fluid
According to the study, the remoras conserved their energy while on their floating island as they surf inside the thin layer of fluid surrounding the whale's body known as the boundary layer, where the drag is less than 72%, which allows the remoras to lift themselves within 1cm from their host to feed and join their mates.
Occasionally, the remoras change directions by skimming or repeatedly attaching and releasing their suction disks on the body of their floating island.
The scientists believe that the Venturi effect allows the remoras to move freely even if their host moves at a faster speed, Science Daily reported.
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