Swimming with humpback whales is a rare treat. We have over 20 years’ experience choosing the right whales to help you enjoy the best encounter possible.
Tonga's Humpback Whales - The Last Lonely Tribe
Humpback whale migration to Tonga
Humpback whales migrate more than 5000 km from their feeding grounds in Antarctica to the Kingdom of Tonga to give birth, nurse, court and mate. This "Tongan tribe" is even more special than other groups of humpbacks - the last to be hunted, the fewest survivors and the least understood. Hunted until 1979 for their oil, meat and bone, scientists now pursue humpbacks for knowledge while travellers seek them for the thrill of their lives.
The humpback whale season in Tonga
- Pregnant mothers arrive first in mid-July to give birth in warm, shallow water, which is easier and safer for newborn babies as it’s free from the main predators of baby whales, orcas and big sharks. Sometimes the mothers are accompanied by male escorts who are hoping to mate with her that season or the next.
- By the end of July the season is in full swing, with the maximum number of whales present throughout August.
- By mid-September the population is beginning to thin out as individuals begin the long migration back to the feeding grounds. While some humpback whales do remain in Tonga well into October, the density is much reduced, so NAI’A finishes her whale season in the third week of September.
Humpback Whale Facts & Figures
- Length from 40–52 ft (12–16 metres). Weight approximately 40 tons, females slightly heavier than males.
- Distinguished by: unique body shape, the bump in front of their small dorsal fin for which they are named, unusually long pectoral (side) fins, knobbly head and spectacular surface behavior, including dramatic breaching and competitive groups.
- Latin name, Megaptera novaeangliae, means “big winged New Englander” because humpbacks were originally described off New England and have the longest pectoral fin of any whale – which is the biggest single appendage in the animal kingdom, weighing up to three tons and measuring one third of the body length.
- Design of the pectoral fin helps to make long migrations. Leading edge covered in barnacles and tubercles: golf-ball-sized hair follicle lumps. Hydrodynamic experts calculated that these tubercles make the humpback whale swim 30% more efficiently. Others have calculated that just floating and bouncing up and down in waves, humpback pectoral fins may propel the whale forward at 3 knots while sleeping! They swim on average at five knots and can max out at ten knots.
- Life expectancy is estimated at least 40 to 50 years. Humpback whales are believed to mature between 5-10 years when they reach around 12m (40’) in length.
- Newborns (around 15 feet long!) are nursed by their mothers for one year, consuming up to 100 gallons (370 L) of chunky 50% fat milk per day.
- Hanging from their upper jaw is a series of baleen plates made up of a protein substance called keratin, like human hair and fingernails.
- Pattern on the fluke (underside of their tails) enables us to tell individuals apart.
- Small holes all over the whale are caused by parasitic cookiecutter sharks that use sharp teeth in their lower jaws to extract a chunk of flesh from their hosts.
- Dives last 10-15 mins, max 45 mins. Calves must surface to breathe every 1-5 mins.
- Blow: bushy, heart-shaped blast of mist about 15 ft (5 m) high is the result of air and water vapor launched at 900 mph (1400 kph). Don’t let this get on your camera or in your lungs.
- Whales breathe voluntarily and may shut off half of their brains when sleeping as do dolphins.
Humpback Whale Behavior
- Humpback whales are well known for active behavior, especially near or even above the surface: spy-hopping, tail-slapping and pec-slapping, peduncle throws, charging and chasing.
- Most dramatic and exciting is the breach during which the whale launches its entire body out of the water with just 2 to 3 flicks of the tail, making this muscle the strongest in the animal kingdom. Breaching could be a form of communication, warning, play or exercise to improve breath holding ability.
- Bull Runs (heat runs, rowdy groups): competitions between males for dominance. They race each other, ram and crash into each other. Sometimes you will see blood in the water and occasionally they get killed. This is a dangerous time to get in the water, but great to watch from the safety of this large, steel boat! We can follow them at 10 knots and they will not even notice us because they are so focused on their competition.
- Male humpbacks “sing” long and constantly evolving songs. Each song lasts 10-20 minutes, but could last for more than 24 hours.
- Cetaceans have no vocal cords, so whales generate their songs by forcing air through their massive nasal cavities.
- Purpose of the vocalizations not completely understood; it is believed to attract females or establish dominance over other males.
- The song across the South Pacific is the same at the beginning of the mating season but changes independently in each region as the season progresses, leading one researcher to speculate that the song is an oral history for the whales, synched in the feeding grounds and then modified for each different region during the mating season.
Humpback Whale Conservation Status
Until commercial whaling - and more recently large-scale illegal whaling from Soviet ships - devastated the species so effectively, southern ocean humpbacks wintered in Fiji as well as Tonga and were seen in large groups as late as the 1960s.
- Over 200,000 humpbacks were killed by whalers in Oceania during the 20th century, reducing the population by up to 70%.
- Recent investigations revealed that 48,477 South Pacific humpback whales were killed by the Soviet fleet between World War II and 1972, of which only 2,700 were reported.
- 25,000 were illegally killed by the Soviet fleet in just 1959-62 as they migrated from Antarctica past New Zealand on their way to Tonga and Fiji.
- Worldwide population is currently estimated to be around 80,000, with the Tongan population about 2,300.
- Besides whaling, whales are vulnerable to collisions with ships, entanglement in fishing gear and noise pollution. Given all this information the International Union for Conservation of Nature (IUCN) declared the Oceania humpback subpopulation as Endangered in 2008.
- The King of Tonga banned whaling operations in Tongan waters in 1978 and since then numbers have been slowly but steadily rising.
- One of the scientists working with the South Pacific Humpback Whale Consortium has discovered by DNA analysis that humpback whale meat is still being sold in Japan. Clearly humpback whales are not "saved".
One thing is certain. The planet's quintessential symbol of conservation, the humpback whale - like all whales - needs protection more now than ever. To fight the whaling lobby and win, we must make whales more valuable alive than they are dead.
“Joann & I had a remarkable experience here in Tonga! Our diving trips mostly entail liveaboard boats and this one was the best yet – great crew & great food! You are fortunate to have the ownership in place to allow you to do it right! We won’t easily forget our “Whale Week” on NAI’A – it’s a once-in-a-lifetime gig!!”
~ Terry & Joann