Tonga's Humpbacks

What kind of whales live in Tonga?

The Tongan whales are humpbacks: moms, dads, and babies (called calves). Humpback whales are called humpbacks because of the way the bend their backs before diving: it makes a hump.

What's special about humpback whales?

Humpbacks are known for for being great acrobats. They do lots of tricks that people enjoy watching. Some of their favorite moves are:

• Breaching is jumping completely out of the water and splashing back down.
• Spyhopping is floating upright with the whale's head sticking out of the water so it can see what is going on.
• Barrel-rolling is using the pectoral fins to spin in the water, slapping with the fins as they spin.
• Slapping is when the whale lifts its flukes or fins out of the water and slaps them back down on the surface, making lots of noise and splashing.

What do humpback whales eat?

Humpback whales mainly eat krill (tiny shrimp) and small fish that swim in big groups, called shoals. Humpbacks have a number of tricks for catching and eating their food:

• Lunge-feeding is when the whales swim through shoals of fish with their mouths open, gulping down water and fish.
• Tail-flicking is when the whale lies on its back with its belly up, and flicks its tail out of the water, throwing its food up into the air and back down into its mouth.
• Bubble-netting is when the whale swims in a circle blowing a stream of bubbles. The confused fish swim inside the rising bubble net. The whale then swims to the bottom of the net and gulps down all the fish "caught" within.

Do the whales always live in Tonga?

This group of humpback whales is just visiting Tonga for winter vacation. Most of the year they live in cold Antarctic waters. They start arriving in Tonga in June, and depart in October.

Why do the whales visit Tonga?

The humpback whales come to Tonga to have their babies! Humpback whale calves don't have enough fat in their bodies to survive the cold Antarctic waters. So their moms travel to the warm waters of Tonga to give birth.

Why do the whales leave Tonga and go to live in the Antarctic?

Tonga doesn't have much food for humpback whales. In fact, the humpbacks don't eat much at all while they are visiting Tonga. They need to return to the Antarctic as soon as the calves are strong enough to survive the trip, so the adult whales can eat. A whale mom may lose 25% of her body weight during her visit to Tonga!

How many Tongan whales are there?

About 100 years ago, there were lots and lots of southern humpback whales. Unfortunately, during the past 100 years people killed most of these whales. In the 1800s, there were about 100,000 Southern humpback whales. Today there are between 3,000 and 15,000 Southern humpback whales. (It is very difficult to count whales!) About 300-500 whales now visit Tonga each year.

Do Tongan whales play with other whales?

No. Even though all the Southern humpback whales migrate to the Antarctic, the different groups don't mix. The whales from Tonga don't mix with those from Australia or New Caledonia. They never even see the Northern humpback whales, who spend their summers in the Arctic.

Do all humpback whales look alike?

No! Every humpback's tail looks just a little different from every other whale's. It's a little bit like every human's fingerprints, which are unique, too. You can tell whales apart by seeing their flukes. That's one way scientists can tell whether they are seeing the same whales from year to year.

You can also tell Southern humpbacks, like the ones in Tonga, from Northern humpbacks, who live in places like Hawaii. Southern humpback whales have white tummies, while Northern humpback whales have dark tummies!