Humpback Whales Stealing the Show
By Jake Keeton

1. News

We have been having amazing sightings during our recent cruises. From the ever-present Bottlenose Dolphins, to large pods of Common Dolphins coming in from the deep and Bryde’s Whales feeding on Penguin Bait Balls. In the midst of all the excitement over the last two weeks, the Humpback Whales have arrived in a big way to remind us that they are large and in charge. Looking at our sighting report for our last ten cruises, we can comfortably say that we are currently experiencing the best Humpback Whale Season that we have had in 25 years. There have been so many Humpbacks moving through the bay that we simply cannot get to see all of them in one day. We find ourselves being spoilt for choice during our cruises, assessing the behaviour of the different pods of whales and choosing to approach those which we feel will provide the best sightings for our guests, leaving the shyer cow-calf pairs undisturbed.

The Humpbacks that are currently passing through Algoa Bay are on their way back down to their summer feeding grounds in the South Seas. Having given birth a couple of months ago, adult females are spending some time in the shallower, more sheltered areas of the bay. This gives their calves a chance to rest, breast feed and play to build their strength for the journey ahead. Aside from the cow calf pairs, pods of boisterous males are chasing after and competing for receptive females.

The following shots from a recent rainy day are a good representation of the variety of behaviours we have been observing. Together with the breaching, mating and fin slapping we observed something quite rare. Close to St Croix Island we came across a female humpback 'tail-sailing" as her calf slowly circled around her making the occasional long dive. Tail-sailing is when the whale hangs vertically in the water with its tail fluke high in the air above the water surface for a considerable amount of time. To date, researchers have surmised two theories as to why whales perform this behaviour. The first theory is that whales are built to be able to withstand the cold waters of the South Seas, it makes sense then that they might need a way to cool themselves down when they find themselves in warmer tropical waters. Holding their large wet tail fluke in the air allows the cool sea breeze to cool the blood flowing through the tail fluke which then cools the rest of their body.

The second theory is that this position could make it easier for young calves to feed. Young calves cannot feed for very long before they need to head to the surface to take a breath. With the mother 'tail sailing' her mammary gland is closer to the surface, allowing the calf to feed for longer before quickly popping up to breathe.

The fact that we may never fully understand the behaviour of whales makes them even more fascinating to watch.

Adult Humpback Whale breaching near St Croix and Brenton Island. This individual proceeded to breach and slap its pectoral fins for 15 minutes. We found it interesting that this individual was breaching at the same time as two other Humpbacks which were further out to sea, as soon as this one stopped so did the others. There is definitely much more than meets the eye. 

Humpback whales often get into a 'rhythm' when breaching, this individual breaching 8 times with roughly 10 seconds and 40 meters between each breach.

This Mother Humpback Whale kept its tail out of the water for roughly 10 minutes while her calf slowly circled her. This behaviour is called 'tail sailing'. 

Humpback calf circling mum

Adult Humpback Whale swimming on its side, slapping its pectoral fin on the waters surface. The sound of the 'slap' on the calm water was like a gunshot going off. A Humpbacks pectoral fin is the largest appendage in the animal kingdom, reaching up to 16 ft (4.8 meters) in length

Something we always wish to see is a Humpback Whale lift its tail out of the water. Unfortunately this normally happens as they make a deep dive and one will then need to wait a while before the whale surfaces. Thankfully other times the whale just goes down to gain some speed for a spectacular breach.