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 Travel & Outdoors | December 2005 
The Spectacular Humpback Whale - 1
 Griffin Page - Naturalist/Eco-Guide
Every year, the most acrobatic of all whales, the Humpback, visits the Bay of Banderas in order to reproduce and give birth. Its arrival begins around mid to late October and extends to around end of March. During that time, some female whales give birth while others reproduce before returning to their feeding grounds in the north.
It is believed that these animals date back to the Eocene era, some 60 - 65 millions years ago and belong to the family of early mammals known as the Mesonychids. Mesonychids, it is also believed, were some of the first land dwelling mammals. These ancestral creatures were furry, had four legs, a tail, carried their fetuses until birth and nursed their young.
Perhaps, they eventually discovered food was more easily available in shallow waters of the oceans, and through the long process of evolution, began adapting to aquatic environments to finally leave land behind them for good. Many links are still missing in this theory just as we are missing links in the theory of our own human evolution.
A little bit of history
The earliest reports of whale sightings in the Bay of Banderas, date back to 1858 and mention the presence of mainly 2 species: the Humpback and the Grey whale. As a matter of fact, the bay was called Humpback Bay in the mid 1800's. Unfortunately, these reports come from log books of American whaling ships.
Many species of whales were hunted from the mid 1800's to mid 1900's. The humpback suffered great losses due to his closeness to shores and his relatively slow speed. At the time, a lot of commerce depended on whale based products. It was hunted for meat, oil which they used in street lamps and machinery lubrication, and the baleens were used to make corsets so the ladies could display a perfect hourglass figure. In 1946, the International Whaling Commission was created to regulate whaling, but some nations didn't abide by the rules.
Thankfully, a ban on all commercial whaling took effect in 1966 due to the growing public and scientific concern. It is estimated that the original population was numbered at around 100,000 individuals. By the 1960's, it had plummeted to a mere 6000 individuals. Today, the world's population is estimated to be between 10,000 and 20,000. The Humpback whale is still listed as endangered in the IUCN Red Data Book.
The Humpback whale is one of the most studied marine mammal and yet, we still know very little. One important trait of the Humpback whale is that each individual has a unique color pattern on the underside of its tail (more properly called a fluke), and which displays designs in varying tones of white, grey and black. This particular characteristic makes it possible for us to identify each different individual by simply taking a clear photo of the underside of its fluke.
This way, we can, over many years' time, know who is where and doing what with whom. This also permits us to count and estimate the number of individuals of a certain population. A little nosy aren't we? Well, let us be nosy because the more we know and understand about these magnificent creatures, the more apt we are at protecting them and assuring their survival as a species.
Why is it called the Humpback?
We can clearly see from the anatomy diagram of the humpback whale that it doesn't really have a hump on its back and even has a relatively small dorsal fin, so why the name? Well, it actually comes from its diving technique. Of all the marine mammals, this is the one that can arch its back so much when it dives down that it actually creates a hump. And of course, hence came the name.
Their enchanting music
Perhaps in the past, you have heard recordings of enchanting underwater music. Maybe, you didn't know that some of these songs are performed by sexually mature male humpbacks and that these only occur in the mating grounds. For this reason, it is believed that males sing in order to impress and attract females but this theory has not been proven as of yet. Why do we call it a song and not communication? Well first, these melodies are just that, melodies.
They have verses and are structured just like our music. They have a certain repetition pattern and if you listen carefully and long enough, you can discern the similarities to our own musical compositions. Second, every year, the same song is repeated with a slight variation; a verse is changed, a new part is incorporated. Every 5 to 8 years, you end up with an entirely new composition.
We know that whales do not sing in their feeding grounds or during the migration south and that they do not travel in pods either. Therefore, some interesting questions arise: How come all the whales from a same population sing the same song, whether they are in Hawaii, Banderas' Bay or Revillagigedo Islands, and how do they learn it?
Perhaps we should reassess our definition of a pod. Possibly, for the humpback, traveling in a pod may mean traveling kilometers apart. However, just like us humans, there are good singers and well, some that are not so good. It appears that maturity and experience has a lot to do with how well and how long a whale can sing. Typically, a male Humpback will sing for approximately 20 minutes, surface for a few breaths and go back down to resume his vocalization. This process can be repeated for a very long time.
The usual positioning of a singer is to be motionless, head facing down towards the bottom of the ocean - for better sound distribution - with its fins slightly open to about 45 degrees. Humpbacks can remain underwater without breathing for a maximum of about 35 - 40 minutes and certain whales can sing for up to 30 minutes. You can listen to a sample of their music on the Natural Treasures’ web page listed below as well as on one of our tours, if a signer is present, as we carry hydrophones on board.
Loving and caring mothers
Calves are born tail first, measure an average of 16 feet (5 mts.) and weight around 3 tons (1,400 kgs.). Newborns tend to sink and have a little bit of difficulty swimming at first. The mother tends to support it with her back and push him up to the surface regularly for him to breathe. Mind you, being aquatic animals, it doesn't take him long to acquire the necessary coordination that enables him to swim on his own. He also soon discovers that his mother's huge tail creates a kind of counter current which follows her and so, he learns to place himself in that area in order to hitch a ride.
This allows him to keep pace with the adults during the migration which is a dangerous time for newborns. The relationship between mother and calf is a tight one. They remain close to each other throughout the first year. He will get nourishment by nudging the lower ventral part of his mother's body which will then release a very rich and thick milk similar in consistency to cottage cheese. A baby Humpback whale drinks 75 gallons (284 liters) of milk a day, the equivalent to that which is consumed by a human baby in one year! He will double in size and weight in the first year alone.
Mothers are very loving and caring with their offsprings. Their huge pectoral fins, used as tactile organs, play an important role in the mother / calf relationship. Females give birth to only one baby at a time and take care of their young for a full year. Since gestation is also almost a year (11 - 11.5 months), they generally give birth every 2 to 3 years.
"Nature could be such a wonderful teacher if only we saw it for what it really is." --Monachí
Natural Treasures invites you to witness the beauty and to lend a hand in the conservation of our natural environment.
Griffin Page is a nationally certified whale watching guide as well as a very knowledgeable eco-tour guide. She helps in the research and conservation of Humpback whales and Olive Ridley marine turtles by conducting informative tours here in our Bay. Information on how you can give donations and other necessary materials or reserve a tour is available through her. Join her in this wonderful endeavor!
You can contact her through:
Natural Treasures Vallarta at:
044-322-888-4617 (from Puerto Vallarta)
naturaltreasuresvallarta@yahoo.com
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