Humpbacks are the most acrobatic of the great whales, and in the breeding grounds they put on a show for a reason. Here are the ten moves you will see on a West Maui whale watch, from the least to the most dramatic, and what researchers think each one means.
Photo: HIHWNMS / NOAA
The first thing most people see. A humpback exhales about 90 percent of its lung volume in a fraction of a second, and the warm, oily breath condenses into a bushy column 10 to 15 feet tall. From the Honoapiʻilani Highway lookouts you often spot the blow long before the whale. Humpbacks usually blow three to five times, then lift their flukes and dive for 5 to 15 minutes.
Photo: NPS / Glacier Bay National Park, public domainThe showstopper. A 40-ton whale drives upward with two or three powerful tail strokes and clears most of its body before crashing back on its side. The slap carries for miles underwater, so breaching is thought to be long-distance signalling, a display of fitness in competition pods, and sometimes a way to knock off barnacles and whale lice. Calves breach constantly while they learn. Watch for a second one: breaches often come in sets.
Photo: HIHWNMS / NOAA, public domain
Humpback flippers are the longest of any whale, up to 15 feet, a third of the body. Rolling on its side or back, the whale lifts one or both and slaps them flat on the surface, sometimes a dozen times in a row. Females in the breeding grounds often pec slap when males are close by, and mothers use it to communicate with calves. The report is loud enough to hear from a boat 100 yards off.
Photo: Eric Kilby, CC BY-SA 2.0
The whale hangs head-down, raises its flukes high and smacks them down, over and over. Where a breach says hello, a tail slap often says back off. Mothers lobtail when boats or males press too close to a calf, and males do it in competition pods. If a whale starts tail slapping near a vessel, a good captain backs away.
Photo: U.S. Navy photo, public domain
The most violent thing a humpback does at the surface. It whips the whole rear third of its body, the peduncle, sideways out of the water and slams it down on, or at, another whale. You see it in competition pods when an escort is fending off a challenger, and from mothers driving away persistent males. The spray can hang in the air for seconds.
Photo: HIHWNMS / NOAA, public domain
A surging push of the head above the surface, throat pleats showing, usually at speed and straight at a rival. Head lunges are the stuff of Maui's competition pods: a dozen males jostling for position behind a female, exhaling hard, lunging and throwing their chins over each other's backs. A chin-slap variant, the head slap, lands the whole lower jaw on the water.
Photo: NOAA Photo Library, public domain
The whale rises slowly and vertically until its eyes clear the surface, holds for a few seconds, then slips back down. A humpback's eye sits low on the head, so it has to come almost to the pectoral fins to see above water. Spy hops are how whales look at boats, and the reason the quietest, eye-level vessels get the closest looks.
Photo: NOAA Sanctuary Collection, public domain
After the last blow in a breathing sequence the whale rounds its back high, the small dorsal fin and tail stock rising in a hump. It is the move that gave the species its name, and the cue that a deep dive is coming. Count to three: if the flukes come up next, you have time for the photo.
Photo: Public domain
Flukes lifted clear of the water mean a long dive, often 10 to 20 minutes in the breeding grounds. The underside pattern of black and white, with its nicks and scars, is as unique as a fingerprint. Researchers and the Happywhale citizen-science project have matched thousands of individual whales between Alaska and Hawaiʻi this way. Your photo could add a sighting.
Photo: HIHWNMS / NOAA, public domain
The whale sinks away without raising its tail. It usually means a short, shallow dive: the whale is travelling or resting near the surface and will be back up within a few minutes, often close to the same spot. Mothers with young calves dive this way so the calf can keep up.
Photo: NOAA Photo Library, public domainBehaviors come in patterns. A travelling whale blows three to five times at intervals of 15 to 30 seconds, arches, lifts its flukes and dives for 5 to 15 minutes, then surfaces a few hundred yards further along. Once you know the rhythm you can predict where it will come up and have the camera ready. Captains and naturalists do this all day.
Surface-active behavior, the breaches, slaps and throws, usually means something social is going on: a competition pod, a mother warning off a male, a calf playing. When one whale starts breaching, others nearby often answer. A single breach is worth watching for a minute; there is often a second and a third.
The rowdiest thing you can see is a competition pod, also called a surface-active group: a female, her primary escort, and anywhere from two to twenty challengers trying to displace him. The pod travels fast, often 8 to 10 miles an hour, with constant head lunges, peduncle throws, tail slaps, bubble streams blown to screen a rival, and bodies thrown across one another. Males bleed from barnacle scrapes and tubercle cuts. It can go on for hours and cover miles of the channel. Your captain will stay well off and let it come past.
Boats are required to stay 100 yards from whales, but whales can do what they like, and curious ones, usually juveniles and calves with a tolerant mother, sometimes swim right up to a drifting boat and circle it, spy hopping, rolling to look up at the people, passing underneath. The captain cuts the engines and waits. This is called a mugging and it is the best thing that can happen on a whale watch. It happens more often to small, quiet boats that are sitting still than to anything big and noisy.
Nobody has proven why humpbacks breach. The leading ideas are long-range communication (a 40-ton splash is audible for miles underwater), display in competition, and parasite removal. Whale Trust and the sanctuary have been studying behavior in the ʻAuʻau Channel since the 1970s, and the honest answer to most "why" questions is still "probably several reasons at once."
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