It's that time of year again! Large winter swells have begun to hit the north shore, Lahaina is getting those cold 65 degree nights (brrr!), and the waters off Maui have begun to teem with the splashes of acrobatic whales. Whale season in Maui has officially begun, and our Maui whale watching tours are already reporting a healthy amount of action. To get you prepped for this upcoming whale season, here are ten facts about humpback whales in Maui that will offer some insight into Hawaii's favorite mammals.
1. What kind of whales are in Maui?
On 99.9% of Maui whale watching tours you're going to be watching humpback whales. Although rare species such as false killer whales and pilot whales occasionally will be seen closer to shore, it’s the aerial, acrobatic humpbacks which make for enthralling Maui whale watching experiences that the island has become so famous for.
2. Where do these whales come from?
Technically these whales are from Maui since this is where they were born! In practical terms, however, the humpback whales have migrated here from the nutrient-filled waters of Alaska. During the summer months the humpbacks will gorge themselves on schools of krill and small fish, and once the water in Alaska becomes too cold for their liking, they begin the long journey south. For expectant mothers, the migration is more about survival than comfort; since newborn calves haven't had the chance to accumulate large amounts of fat stores, they would most likely freeze within days of being born in the cold waters of Alaska. Although humpbacks from Alaska will also migrate to Mexico and the islands of the western Pacific, the majority of North Pacific humpback whales choose to spend their winters in Maui.
Image courtesy of Hawaiian Islands Humpback Whale National Marine Sanctuary
3. So how big are they?
Humpback whales are the world’s 5th largest whales and can grow to between 40-50 ft. Females are often a bit larger than males due to reverse sexual dimorphism, which is a fancy way of saying that they grow bigger than the males so that they can give birth to a 12 ft., 2000-lb. baby! When it comes to their weight, adult humpbacks weigh about one ton per foot, which means that a 20 ft. humpback would weigh 20 tons, and a full-grown adult can weigh upwards of 50 tons!
4. So what do the whales eat while in Maui?
Actually, humpback whales will go the entire time they spend in Maui—up tofour months—without eating anything at all. Consequently the adult whales will lose up to 1/3 of their body weight during their winter vacation. The reason why adult whales don’t eat while they’re in Hawaii is simply because there isn’t anything for them to eat, even if they wanted to. Unlike toothed species such as sperm whales, humpbacks are equipped instead with baleen, a hard substance made out of keratin that also comprises human fingernails.
In a process known as “filter-feeding” the whales will expand their ventral pleats to ingest the same volume of water as a hollowed out African elephant, and they then use the plates of baleen to strain out any krill, plankton, or small fish which may have been caught up in the gulp. The water passes through the baleen, and whatever food is left behind is consequently swallowed. Because Maui’s waters are so warm, however, they are devoid of the whale’s primary food source, so attempting to feed while in Maui would be the equivalent of taking a huge gulp of water and then spitting it all out.
5. But the calves must be eating somehow in order to grow?
Even though adult humpbacks don’t eat for the entire time they’re in Maui, the calves are nursing mom’s milk. Unlike 2% milk which we might buy in the grocery store, however, whale’s milk is close to a 40% milkfat, thereby making it more of a yogurt or cottage cheese. The calves will consume up to 100 gallons of this milk on a daily basis, and due to the copious amount of feeding they can actually gain anywhere from 7 to 10 pounds every hour!
6. So why do whales come to Maui?
Although humpback whales can be spotted throughout the entire Hawaiian Island chain, of all the humpbacks which migrate to Maui, the majority are found in the shallow waters between Maui, Moloka‘i and Lana‘i. There was a time only 18,000 years ago when the four islands of Maui, Moloka‘i, Lana‘i, and Kaho‘olawe all comprised a large island known as Maui Nui (which was slightly larger than the current size of the Big Island).
At the end of the last ice age, however, scientists estimate that sea levels in this part of the Pacific rose an average of 300 ft., thereby spilling into the valleys of Maui Nui and inundating the low-lying areas. The end-result of this occurrence was that Maui Nui was splintered into the four islands which comprise Maui County today. The reason this is important for the whales, however, is that whereas areas such as the northern shores of Maui and Moloka‘i have water which is thousands of feet deep, the waters in the islands of Maui County average only 300 ft. Consequently, this area forms a safe, protected body of water that is free of large, toothy predators (such as Orca), and is the perfect “kiddie pool” for nurturing newborn calves.
7. How long does it take the whales to travel between Maui and Alaska?
Humpbacks definitely have it harder than humans when it comes to traveling between Hawaii and Alaska. Whereas us humans can make the journey from Maui to Anchorage on a 5-hour flight, it can take the humpbacks in the range of 6-8 weeks to successfully navigate their way from the feeding grounds to the breeding grounds. Seeing as there isn’t anywhere to stop along the way to take a rest, it’s believed that the humpbacks make a continuous, non-stop journey at an average speed of 3-5 mph.
8. So how do whales navigate during the journey?
As anyone who has ever gone scuba diving can attest to, when there are no landmasses to use as reference points it can be pretty easy to get lost. Amazingly, these fascinating humpbacks successfully navigate to the most remote islands on Earth amidst a sea of blue which looks the same in every direction.
Intriguingly enough, autopsies have shown that humpback whales have trace amounts of a naturally-occurring substance called magnetite that exists in the forefront of their brains. As the name implies, magnetite has magnetic properties to it, and it’s believed that the whales use this magnetite as a means of tapping into the magnetic pull of the Earth to determine which way they need to travel.
9. OK, but now the big question: Why do whales breach?
The honest truth is that no one knows for sure. There are a lot theories floating around out there—such as that they are using the force of the impact to slough barnacles off of their skin, or that they are working out their tail muscles for the long journey back home—but the most accepted answer that everyone can agree on is simply because they can.
The reason why humpbacks are so aerial in the first place is that despite being only the 5
largest whale, they possess the
strongest muscle in the animal kingdom
known as the peduncle. Occupying the latter third of a humpback’s body, the peduncle muscle is so strong that even a fully-grown adult is able to propel themselves entirely out of the water with only two or three flaps of their tail flukes.
10. Ok. I’m sold. So when is the best time to go on a whale watch in Maui?
Although the first whale sightings will usually occur sometime in October, whale season officially runs from December 15-May 15. Since activity tapers towards the end of the season, however, most Maui whale watches stop running sometime towards the end of April. While sightings are possible all the way until the first week of June, the peak of the season with the most activity is from January 15-March 31.