Basking sharks appear to be slow-moving and gentle, but they sometimes leap out of the waters, as explosively as the great whites, according to new research.
Despite their peaceful demeanor and large size (they are the second largest shark species in the world), basking sharks can be as agile and powerful as their more famed counterparts, the great whites.
A new study published in Biology Letters focuses on the fact that they can leap right out of the water, as high as 1.2 metres if they choose to.
To study this breaching behavior, Dr Jonathan Houghton (from the School of Biological Sciences at Queen's University, Belfast) and his colleagues attached a monitoring device to a basking shark near Ireland—and managed to capture its breaching activity after just three hours. This particular shark measured eight meters long and weighed 2.7 tonnes.
The breaching behavior of 20 basking sharks was also filmed from the shore by another member of the research team.
In their analysis, they calculated that to achieve the breaching height of 1.2 meters, the basking sharks would have to accelerate to a speed of 18 kilometers per hour just before breaching—the same speed achieved by great whites. However, because they are nearly twice as large as great whites, they would have a greater energy expenditure—specifically 45 to 51 kilocalories.
Considering that this amount of energy accounts for nearly 1/17th of their daily standard metabolic cost, and their diet consists mostly of zooplankton which is found underwater and not in the air, why then do basking sharks breach?
Unfortunately, this question would need to remain unanswered for now. “At present, it’s a mystery,” said David Sims at the Marine Biology Association in Plymouth, UK, in a New Scientist article.