Oct 082009

Just last week, I returned from a trip to Tonga, an island kingdom located in the Pacific Ocean, about a thousand miles (1,600 km) northeast of New Zealand. Tonga is one of the few places in the world that you are allowed to swim with whales.

It was an awe-inspiring experience. These are pictures from our trip:

Whale calf ascending from the depths

Curious calf

Return to the mother ship

. . . and, the mother ship

About the Humpback Whale

Humpback whales are baleen whales (versus toothed whales like orcas).

Their name comes from the way they arch their backs when they swim or dive at the surface.

Humpback whales migrate enormous distances between their summer and winter feeding grounds. One recent study found humpbacks that migrated up to 5,100 miles, the longest migration distance recorded for any mammal. The humpbacks that we swam with in Tonga belong to the Southern Hemisphere population. They don’t mix with the populations in the Northern Hemisphere. These southerners can be distinguished by the white coloration on their bellies and underside.

Whales can be identified by the unique patterns on their tails, or flukes.

The Southern Hemisphere whales feed on krill and small fish during the summer, which they spend in Antarctica. They spend their winter in Tonga, where they find mates and raise their newborn calves. Opportunistic feeding can occur during this time, but mostly they live off their store of body fat from the summer. During this time, nursing calves may gain more than 2 pounds (around 1 kg) per hour. This is why female whales are generally larger (about 52-56 feet in length, versus 49-52 feet for males). For some perspective, a mature humpback whale is slightly longer than a big yellow school bus. For another visualization of the whale’s size, check out this illustration in the Encyclopedia Britannica. A fully-grown whale weighs about 44 tons.

The scientific name of the humpback is Megaptera noveangliae. This means “giant wings”, which refers to their large front flippers that can reach a length of about 15 feet (4.6 m)!

Here, a swimmer in the water watches a humpback whale slapping its pectoral fins.

Humpbacks are known for their acrobatic antics. These behaviors include:

fin slapping

tail slapping

and spectacular breaching

Curiously, there is no consensus on why the whales do this. Is it for communication, due to aggression, an expression of exuberance? There were times on this trip when each of these explanations seemed plausible. Scientists do know, however, that the humpbacks keep their eyes open when they breach. So perhaps they’re taking a look around.

In the Ha’apai Island group in particular, I would look up just in time to see the improbable image of a gigantic whale, seemingly balanced on the tip of its tail, suspended on the horizon for an instant, before it fell back to earth in an explosion of water. It was only through the sound and size of the splash that I could comprehend what I had just seen.

For more pictures of whales from our trip to Tonga, click here.

Humpback whale calf

Whale Origins

It’s thought that the closest land mammal relative to the whale is the hippopotamus.

A paper recently described in the online website Science Daily also suggests that around 50 million years ago whales transitioned to the water while still vegetarian, but that they still retained the ability to walk on the land as they developed their carnivorous diet.

Although today the endangered humpback whale population is recovering, it is still at a fraction of its pre-whaling population. Recent studies in particular show that the southern Pacific populations are recovering at a slower rate. Humpbacks and other whales face dangers from entanglement in fishing gear, boat collisions, and noise pollution. In recent years, humpback whales have also been faced with the threat of whaling under the Japanese “scientific whaling” permit. Humpback whales also face pressure from shrinking antarctic foraging zones due to climate change.

Learn more and take action:

American Cetacean Society: A resource for learning more about whales of all varieties.
Wikipedia: Humpback Whale
Underwater Times Whale news from around the world.
Tagging of Pacific Predators (TOPP): part of the landmark Census of Marine Life. This tagging project plans to provide near real time tracking of humpback whales.
NRDC: Efforts to address noise pollution, including dangerous levels of sonar used by the US Navy.
Provincetown Center for Coastal Studies: Learn about techniques used to free whales from fishing lines and nets.
Oceanus Magazine: Check out this article about new techniques being developed to sedate whales in order to disentangle them from nets.
IFAW (International Fund for Animal Welfare): Learn more about efforts to stop commercial whaling.
Whale Wars: The second most popular show in Animal Planet’s history.

  3 Responses to “Swimming with Humpback Whales in Tonga (Part I: All About Humpbacks)”

  1. Looks like a fantastic trip. Beautiful photos of the whales!

  2. FRIGGIN AWESOME!! Zack and I actually talked about doing this – but then we never made it to the pacific…boo!

  3. Your photos are incredible!!! I cannot believe how close you were to the whales. I also enjoyed your write up.

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