Icy Straits
A juvenile humpback whale erupts out of Icy Straits, streams of water cascading from its pleated throat, flippers flinging diamond arcs of spray. For a fraction of an instant it hangs in the sunlight and then – KA-WHUMP! – it splashes down again with a resounding impact that echoes from hill to hill across the quiet sea.
Why? Why do whales breach? Marine mammalogist Fred Sharpe suggested to us, as we watched the youngster repeat the performance again and again, that it could be using the tremendous sound of its re-entry splashes to call to its mother, who is likely nearby, feeding with a group of adults. Just like human babies, this young whale’s priority is nursing from its parent and it may be throwing a tantrum to let her know that it is hungry! Later in the day, as we enjoyed cocktails and hors d’oeuvres on the bow while watching another group of humpbacks off Point Adolphus, ecologist Steve MacLean offered a different line of reasoning. Using a quick “cocktail napkin calculation” Steve estimated that the energetic cost of breaching for humpbacks is very low, only the equivalent of about 86 herring, a small fraction of a whales daily intake. If the cost is this low, it seems very reasonable to speculate that humpbacks, and other whales, breach just because they can – possibly simply for the fun of it.
These erudite speculations on an interesting point of whale biology are excellent food for thought, but our questions remain. Why do whales breach? Why do we see them sometimes singly and sometimes in apparently cooperative groups? What is their world like, below the surface? How can they locate their prey in the darkness and cold of the depths? What might they think of us, on our ships, watching and wondering about them? No matter how good the answers, the questions return. And a long Alaskan summer day in Icy Straits is the perfect place to ask them, and ask them again.
A juvenile humpback whale erupts out of Icy Straits, streams of water cascading from its pleated throat, flippers flinging diamond arcs of spray. For a fraction of an instant it hangs in the sunlight and then – KA-WHUMP! – it splashes down again with a resounding impact that echoes from hill to hill across the quiet sea.
Why? Why do whales breach? Marine mammalogist Fred Sharpe suggested to us, as we watched the youngster repeat the performance again and again, that it could be using the tremendous sound of its re-entry splashes to call to its mother, who is likely nearby, feeding with a group of adults. Just like human babies, this young whale’s priority is nursing from its parent and it may be throwing a tantrum to let her know that it is hungry! Later in the day, as we enjoyed cocktails and hors d’oeuvres on the bow while watching another group of humpbacks off Point Adolphus, ecologist Steve MacLean offered a different line of reasoning. Using a quick “cocktail napkin calculation” Steve estimated that the energetic cost of breaching for humpbacks is very low, only the equivalent of about 86 herring, a small fraction of a whales daily intake. If the cost is this low, it seems very reasonable to speculate that humpbacks, and other whales, breach just because they can – possibly simply for the fun of it.
These erudite speculations on an interesting point of whale biology are excellent food for thought, but our questions remain. Why do whales breach? Why do we see them sometimes singly and sometimes in apparently cooperative groups? What is their world like, below the surface? How can they locate their prey in the darkness and cold of the depths? What might they think of us, on our ships, watching and wondering about them? No matter how good the answers, the questions return. And a long Alaskan summer day in Icy Straits is the perfect place to ask them, and ask them again.
