Subject: dolphins
Yeah, its' dolphins. 'nuff said. :-)

https://www.iflscience.com/why...

According to the Encyclopaedia of Marine Mammals, dolphins have been bow-riding ever since there were swift boats on the oceans – even the Greeks wrote about bow-riding in the Mediterranean seas. In modern times, it refers to dolphins exploiting the pressure wave caused by the boat at the front of the vessel.