Behaviour

Dwarf minke whales are highly manoeuvrable, acrobatic little whales which in many ways behave more like dolphins than other baleen whales.

The following pages describe a number of behaviours that have been recorded by members of the MWP research team over 17 years of field observations. A more comprehensive description of these (and other) dwarf minke whale behaviours can be found in:

Mangott, A.H. (2010). Behaviour of dwarf minke whales (Balaenoptera acutorostrata subsp.) associated with a swim-with industry in the northern Great Barrier Reef. PhD thesis, James Cook University.

Figure 1: Dwarf minke whale surfacing for a breath.

Uncommon surface behaviours

Variations in surfacing behaviour include the ‘prolonged surface swim‘ (also known as ‘motorboating‘) where most of the back, from snout to fin, remains out of water as the whale swims along. The whale may take several breaths while maintaining its position at the surface.

Figure 2: A prolonged surface swim by a dwarf minke whale during an interaction with snorkelers

Animals may rise vertically from the water, exposing the snout but not the eye (headrise) or much of the head, with the eye (spy-hop). In our experience, headrise is more common, but both behaviours may allow the whale to see features above the water.

Figure 3: A spyhop – the whale’s eye is exposed above the surface of the water.

Most spectacular are breaches, where the whale comes out of the water, sometimes completely. Most breaches are partial, often with the animal falling back in the water belly up. Most breaches we have seen were in the distance and it was impossible to tell if there was more than one animal. In the few breaches close to the boat where other whales were visible, it seemed to be one animal breaching. While the purpose of this behaviour is not known, for other whale species breaching has been suggested as a way of making noise and alerting other whales to the presence of the breaching individual. It has also been suggested as a means of removing parasites, for “joie de vivre” and signalling the size of individuals in competitive situations.

Figure 4: A breaching dwarf minke whale. (Image courtesy of Ursula Tscherter, ORES)

Swim speed Although most approaches of dwarf minke whales are to anchored or drifting vessels, we have received reports of dwarf minke whales keeping pace for short periods with vessels travelling at over 20 knots. We have also observed a whale catch up to and then repeatedly swim circles around the boat while it was maintaining course towards a reef at 8.5 knots.