27 images Created 20 Nov 2014
Humpback Whales - Blowing and Sounding
Whenever I was looking for humpback whales I was constantly scanning the horizon for the telltale sign of their blows; the plumes of their exhaled breath. One of the most striking views was either in the morning or the evening when volleys of their blows were ignited by the low rays of the sun along the horizon before melting away like misty wraiths. Much less majestic was the nauseating smell of their breath at closer quarters. I was often enveloped in clouds of their stinky fishy breath, especially if I was downwind. Their breath is not only smelly, but also very oily, so I frequently had to clean the residue from my lens. They typically dive for 5-10 minutes, although they can hold their breath much longer. Unlike land mammals that store the majority of air in the lungs, whales store less than 25% in the lungs with almost half of the oxygen contained in haemoglobin molecules. They also store oxygen in myoglobin molecules in the muscles. When they dive, their metabolism and heart rate decreases to reduce the rate of oxygen consumption, and blood is cut off from their extremities. Their enormous lung capacity and oxygen retention enables them to dive in excess of 20 minutes to depths up to 500 ft for foraging. When they surface they have a limited time to exchange the air in their lungs, so it is exhaled with tremendous force in an explosive manner, which vapourises the seawater that is trapped above the two blowholes, creating the visible pillar of water vapour. The inhalation is equally powerful, and at close quarters I was able to view how quickly the blowholes open and snap shut. After a few inhalations they begin to sound by arching their backs into a prominent hump, and then raise their flukes aloft, which sheds a curtain of water, before sliding gracefully into the sea. It is a beautiful balletic sequence that I never tired of viewing and photographing, and as with their blows it was enhanced and illuminated by the rising and the setting sun.