Brydie Storer of Balclutha Primary School asks :-
How can whales spout water out of their spouts?
Alex Davies, a veterinarian at Massey University and who has an interest in whales, responded.
Whales breathe air just like the mammals that live on land. The big difference is that they can hold their breath rather well; some whales dive as deep as 2000 metres and stay under for one and a half hours.
When it comes to the surface, a whale empties its lungs forcefully. This air is moist and condenses in cool air to look like a spray of water.
This is just like seeing your breath on a frosty morning. It also contains a fine oil/detergent mixture that leave a greasy film on what it touches. It smells strongly of bad fish, because it also contains stomach gas that is only released at the surface. The blow rises as high as eight metres for some species and hence whalers could see it from some distance.
After a deep dive, there must be several spoutings to replenish oxygen stores in blood and muscles before the next dive. The shape of the spout depends on whether the whale has two blowholes or one, and on their shape and position. Sperm whales spout forwards and to the left. Whalers knew what they were chasing.
Blowholes are just nostrils, but in animals that feed in the sea they do not need to be near the mouth to smell food as it is eaten. Instead, these nostrils are right on top of the head.
To swim and breathe on the surface, we do the same thing with a snorkel.