What is more magic, more unique than diving and hearing a whale’s singing ? This moment is much more fabulous when you get the chance to swim with whales.
From Moby Dick to nowadays, the same cry can be heard when you see a whale : « here it blows » !
But who are these humpback whales ? what do they in the Polynesian tropical water ? where are they from ? What do we really know it ?
It would be wrong to think that whales are fishes… whales are not fishes !
The whales, as all marin mammals, acquired the ability, after many years of evolution, to be at the same mammal and marin!
The humpback is a marine mammal, classified in the order Cetacea. It is part of whales family. The scientist name is « Megaptera Novaeangliae ». Why do we call them « humpback whale » ? The bump refers to the back of the whale, which makes the round back before going down. The english name « humpback whale » is a good illustration of this.
As all mammals, whales respire air and breast feed their babies. The skin is smooth, soft and delicate. The adults male size around 15-16 meters and 16-17 meters for the femals, for 40 tonnes approximately. The humpback whale can live from 40 to 50 years.
The whale’s species eat exclusively during the summer and live with the fat reserves during the winter. It is an actif predator, hunting krill and small fishes using direct attack or by dazing their preys using their fins.
The humpback whale live in oceans and seas all over the world. We can easily recognize them thanks to the top of the boby, which is totally black and underside rather white the head and the jaw are cover of small protuberances
Whales get an amazing breath capacity. How can we explain their long apnea : from 30-40 minutes for adults and 5 to 20 minutes for children ?
There is not enough oxygen in their lungs to serve the animals when there are underwater. This is the reason why whales have developped oxygen faculties of storage in their lungs but also in muscles and blood. In fact, whale’s blood contain more hemoglobin than in human’s blood.
The whales get this amazing faculty to give birth in the open water
Femals give birth generally every 2 or 3 years, in Polynesian’s water, after 11 months of pregnancy. At birth, the calf measure already 4 to 5 meters for 700 kilograms ! what a beautiful baby it is!
The mother produces a very rich milk fat (40%), excellent source of energy. The calf grows and grows rapidly. The breastfeeding is a little special : the female ejects milk on demand, directly into the mouth of the calf. To suck, the calf comes directly under the mother.
During the six first months, the baby is breast feed by the mother and then he starts find food by hisself. At the beginning of it’s second year, the calf leaves the mother. During the first hours and the first days, the calf has a very clear color, his calf is slightly crumpled and stay in contact of the mother.
Few weeks after his birth, whereas the mother begins to be tired by nursing, the young starts being more free. The femal let him alone go back to the surface to allow it to breathe : he can’t do as much apnea as the adult. He need to breath every 3-5 minutes whereas the mother can stay under water during 20-30 minutes.
The whale’s song
During a dive, i get the amazing chance to hear a whale sung. I was unable to know where it came from but the vibration was so intense and strong in my head.
How describe whales’ s song ? deep, unique, that captivates and enters the body. All the ocean starts to sing and vibrate.
Only males can sing. For that, it always comes in a very special position, tilted, head down, tail to the surface. This position may be required to produce sounds.
Songs are quite the same but do they have the same aim?
We don’t really know how whales learn to sing and we have no answer about why do they sing. One hypothesis explains that songs play an important role in activity love, to attract femals.
Songs could be like a guide means for migrations, allowing animals to navigate and find themselves before they compete. By singing, males create assembly areas
Where do they come from ? Why do we saw whales every years at the same period ?
Hunted for a very long time for their fat, whales are protected today. In the south hemisphere, actually we can account around more than 60 000 whales divided in seven differents population. All these population are in very specifics geographicals areas :
- West coast of Central America
- West of Atlantic ocean
- West of Africa, the population is growing
- South west of Indian Ocean
- South est of Indian Ocean
- West of Pacific, with Polynesian islands, Samoa, Tonga and Cook
- Coral seas, mostly around the Great Coral Reef
Whales move between all these regions at the seasons’ rythm. These migrating species spend the summer in cold water where they feed, but in the winter they go to the tropics where they give birth.
Generally, humpback whales live alone or in a group but only for few hours before they sepparate. Eventually, these groups can stay together more longer to look for food or to hunt.
Migration is not due to chance! This migration is essential for their survival. In fact, whales are obliged to go to tropical waters in winter to give birth and reproduce themselves, and to polar regions in summer to feed. This survival instinct oblige them, every year, to do a very long trip of several thousand kilometers.
The main whale’s food is krill. Durant the spring, melting ice releases millions of krill tons. This is the reason why humpback whales leave in Antarctica durant 4 to 5 months every year, during the heyday.
In winter, Antartica is really what we can call a welcoming sea mostly for calfs. It is too much cold, days are very shorts, the ice extends, storms are sometimes terrifying, food is less abundant and less accessible. Whales don’t have any more reasons to stay : it is the time to go to hotter waters. This is exactly there that they could reproduce and give birth in hot water.
But why coming in tropical waters to reproduce themselves and give birth?
According some specialists, the calf, too small, could be the victim of the cold conditions and also from the predators. Under the tropics, there are many protected reefs, really appreciate from the femals as their babies can have more chance to survey, get stronger… it is also an advantage for the females because they can recover from an exhausting birth and be protected during the nursing.
We can ask one question: How do they do not lose themselves in this ocean, where everything looks the same? what guide whales?
No researcher really has the answer! The presence of magnetite in the brain of the whale may explain it: they can locate the north and orientate themselves. But the mystery still remains unsolved…
Certainly in all cases: the direction taken by whales is guided by their history, in fact animals show a really tendency to run into the place they are born to waters to reproduce and give birth.
Post written by Laure Chaterlard