Abstract

This study confirms earlier observations of apparently involuntary movements, strongly associated with the breathing. The movements include taxes – a dorsal flexure of the thorax and steering movements with the pectoral fins – and a more stereotypic movements, resembling a fixed motor pattern, with the tailfin. In the latter, a downstroke is paired with the expiration, and a powerful, thrust producing upstroke with the inhalation.
The different components are beautifully coordinated into a smooth and highly functional sequence of movements, ensuring that the blowhole is raised above the water at the breathing. Many of the movements are present in sleeping, tranquilized, and beached animals, thereby giving an indicaton of the strength of association with the breathing.
The duration of an expiration and an inhalation was measured for a couple of blows, and was found to be 0.4 and 0.8 seconds respectively.