We are seeing humpback whales almost everywhere in the Whitsundays. The mothers and calves seem to favour the relatively shallow and protected waters — which means they are frequently nearby where we have anchored ADAGIO. E.g., we were recently anchored in Cid Harbour when we noticed a mother/calf pair in a typical attitude: “mum” is resting on the surface while “junior” splashes around – keeping very close to mum.
On this day we observed for the first time a particular humpback nursing behaviour. We noticed that the mother whale was in a vertical posture with her tail flukes almost completely out of the water. We did not stopwatch how long she maintained this pose, but it was a long time – perhaps 20 minutes (we were wondering when she would need to come up to breath).
Steve spent some time with Google, eventually finding an excellent description of what this behaviour is all about. The Oceania.org website on Migration of Southern Humpback Whales: offers a small interactive encyclopedia on humpback behaviours. On the fluke-up nursing posture:
Mothers with young calves spend many hours feeding their young. A young calf can consume up to 120 gallons of milk per day. The mother’s milk is a highly rich substance and contains a high level of fat. Young calves can double their length by the end of the nursing period. Feeding usually takes place with the mother submerging in a horizontal position for approximately 8 minutes at a time with the young calves surfacing for air four or five times during the 8 minutes.
The older calves with a little more body weight finding it harder to submerge, are sometimes fed with the mother adopting a vertical position.
The mother with head down and tail flukes above the surface of the water allows the calf to get easy access to her teats which are just above the tail stem.
In our photo gallery are the results of Dorothy squinting for hours at the tiny little photos we captured of the whale nursing — until she found the photos where she could see the calf nursing right under the flukes. These photos are all about 50% crops of 300mm long telephoto shots.