HUMPBACK WHALES

Tanzania is famous the world over for its annual giant migration of grazers across the Serengeti, but there is another equally miraculous journey that reaches the Indian Ocean waters off the coast of Zanzibar. Between June and December herds of humpback whales and their calves reach the archipelago on migrations that can reach up to 8,000 km. It’s a sight that Ekaterina Kalashnikova, who is the general manager of luxury hotel Zanzi Resort and a marine biologist, has been lucky enough to see many times. Here she shares some amazing facts about these playful leviathans of the sea.

Humpback whales have developed their own unique communication methods

Humpback species are notoriously vocal, and their acoustic repertoire is diverse and impressive, including complex signature songs that may last for hours. But apart from these voice messages that whales use for socialising and conveying information, they also have their own way of ‘texting’ each other. They use pectoral fin slapping for this. It’s a noisy, splashy event that is incredible to witness. Usually a female whale will lie on her side, raise her long pectoral fin into the air and provocatively slam it back to the surface, producing a sound familiar (and desirable) to male whales. No doubt, she’s flirting! So-called pec-slapping is one of the many intricate ways of a non-vocal communication that they use to say ‘hello’ to each other (and perhaps much more than that – if we could speak their behavioural language we would probably hear something like ‘I have arrived, I am attractive and ready to get to know you a bit closer, let’s share these warm and safe waters for increasing abundance of our population’). This is where we start to see how they form complex social bonds and share the culture of communication – their own WhatsAppPecSlap messaging network.

@Pavel Kalashnikov

Humpbacks don’t eat for almost six months and while fasting travel incredible distances!

These majestic marine nomads undertake annual migrations covering thousands of kilometres from high-latitude summer feeding grounds, where they take advantage of the food resources of vast swarms of krill, to low-latitude winter breeding grounds, where they mate, give birth, nurse, and generally do not feed. When southern hemisphere humpbacks are in tropical waters (southern hemisphere winter), the northern hemisphere humpback whales are feeding at high latitudes (northern hemisphere summer). This situation reverses after six months. Each year from June to December humpbacks are observed along the Tanzanian coastline and the Zanzibar and Pemba channels where they come to breed and… to fast.

@Pavel Kalashnikov

@Pavel Kalashnikov

'The big wings of New England’

This is the English translation of the Latin name for humpback whales, megaptera novaeangliae. It’s a deservedly beautiful name inspired by the whales’ giant pectoral fins, which reach up to five metres in length. It is this length of the fins, combined with their shape and extreme mobility, which make humpbacks so acrobatic and manoeuvrable. The natural efficacy of these fins with their tubercles on the leading edge and their fluid-dynamic mechanisms have even been applied to the designs of watercraft, aircraft, ventilation fans and windmills.

Whales cannot breathe through their mouths

Despite being mammals and breathing air just like humans, whales' nostrils have evolutionary moved on to the tops of their heads and merged into a blowhole, which in case of humpbacks have two holes, just like our nostrils. When whales surface to take out a breath and let out mighty blows they are not releasing water from their blowhole they are letting out air. When this happens a huge blast of mist can be seen in the air, which can reach three metres in height and be nearly as wide. The blast can be seen from up to a few kilometres away and, to be honest, it is best experienced at a distance as whales’ breath, which contains mucus and oils, can be a bit smelly. Blows of different species are really iconic as they vary in shapes and directions. Recognizing distinct blow not only helps to locate your animal in the water, but also often enables species identification.

Whales have fingerprints

It is possible to recognize individual humpbacks by the unique markings of their tails (or flukes). These are recorded for individual identification of the animals and ID catalogues compilation. In this way we can obtain information year on year about populations of that species, their size, individual growth, associations, mortality, and reproductive rates. Flukes are whales’ fingerprints. However fluke markings in calves are not persistent so cannot be used for ID purposes.

@Pavel Kalashnikov

Ekaterina Kalashnikova

Cetaceans’ researcher Ekaterina has been working with the Wildlife Conservation Society Tanzania Programme for the five past years alongside scientists and conservationists who have supported in her marine biology journey. She says: “By systematic data collection, having a lot of patience, we can start to gradually unfold more and more of what a whales’ life cycle is about. We are watching them, asking really interesting questions, but still getting very brief glimpses of these sea marvels. Intelligent, peaceful and curious, believed to demonstrate altruistic behaviour, having intricate social communication, these majestic nomads of the seas will forever be captivating minds.”