Question of the month

During an interview with Hal Whitehead, Research Scientist at the University of Dalhousie, Canada, Whales online asked him the following question :

Why do whales breach?

H. W.:

It is estimated that this behaviour often represents the full power of the animal. The whale leaps out of the water, either vertically or almost vertically, only to fall back on its side, its back or its belly. The large splashes that result that can be visible from many kilometres away. Breaches are often performed in bouts. Extreme is 130 breaches in 75 minutes, probably all performed by the same humpback whale in the West Indies!

Not all whales breach this much. The humpback whale, the right whale and the sperm whale breach frequently. The minke whale is much more discreet, except in the St. Lawrence where its prowess is comparable to that of the best "breachers".

So, why do whales breach? Young whales likely breach as a form of play or to develop their muscles. Adults likely breach in certain circumstances to transmit a message to members of their group. In fact, as breaching requires a significant amount of energy, a whale may breach to demonstrate its physical abilities; a very convincing signal. Less often, it seems that there are other explanations for breaching. It could be a technique to help cetaceans feed by stunning or scaring prey. It could be a good way of getting rid of external parasites. It could also be a method for inhaling water-free air in rough weather. Who knows? What is certain is that this behaviour is spectacular for those observing it from the surface!

Portrait of Hal Whitehead