A “Fingerprint” on The Tail (Tells Which Whale).

How the tails of Humpback Whales are a clue for who’s who in the sea.

© Five Star Whale Watching/ Andrew Lees. A Humpback Whale performs a “fluke-up” dive before heading into deep waters. These tails, as outlined below, provide many clues to scientists and observers.

What’s in a tail?

Well, if you’re a cetacean (whale, dolphin, porpoise), then technically speaking your tail is composed of the expected stuff; connective tissue, arteries and veins. Surprisingly, the flukes (a tail is made up of two flukes) do not contain any bones.

If you imagine large whales, it might be difficult to understand how they can move their massive tails in the first place. A cetacean has large muscles for swimming, including the epaxial and hypaxial muscles. These aid in executing the desired “up and down” motion of the tail. The “caudal peduncle” is the narrow region of the vertebrae that meets up with the tail flukes.

The exterior of some whale tails however, can tell a dynamic and revealing story about the life history of the animal. The underside of the flukes is perhaps the most interesting quality when discussing the differences between individuals of certain whale species. To be highlighted here is a favourite species of mine, one of the ocean’s greatest leviathans…the Humpback Whale!

Working as a Marine Naturalist on-board a whale-watching vessel in the Salish Sea, has led me into the world of Humpback Whale identification. Our respectful presence on the water has allowed whale-watching vessels to photograph multitudes of Humpback Whales every single season. Large numbers of North Pacific Humpbacks seek out the cool, northern waters of the Salish Sea to feed; eating constantly through the spring, summer and even fall/ winter months.

I, among many other naturalists and scientists on the water, have an undeniable interest and passion for the movement and life history of these gentle leviathans of the deep. How does one even begin to tell a whale apart, especially when so much of their life is spent underneath the surface? Well, you need a camera, the perfect timing and angle, and of course…a Humpback Whale! After you have captured the perfect “fluke-up dive” photo, you can begin to compare individuals and decipher who might have been sighted.

For those of you that may have never heard the words “fluke-up dive”, it is a casual term for a behavior that is performed exactly as it sounds. Before a deep dive, Humpback Whales are known to usually raise their flukes horizontally/vertically above the surface of the water before disappearing into the depths. When this occurs, scientists, naturalists, whale-watchers or even a passerby on shore has the incredible opportunity to take a glance at this massive tail…tails which may measure up to 18 feet wide! These tails are considered to be as unique to each Humpback as a fingerprint is to a human.

You might be wondering why this is so important to scientific study, especially with how many individuals might be present in an area. Well, Humpback Whales were almost eliminated due to commercial whaling in the 1900’s. When commercial whaling was stopped via moratorium in 1985, dramatic changes occurred for Humpback Whales. With less pressure on Humpbacks globally, they began to recover from the over-exploitation from the previous commercial industries.

When Humpback Whales began showing up more frequently (mostly after 2004 according to MERS), scientists took note of these events. They soon realized that every year there appeared to be more and more Humpbacks visiting the North Pacific! The “Humpback Comeback” had begun. The first well-documented visitor was known as “Big Momma”, and she brought several different calves into Salish Sea waters every summer. As more and more Humpbacks began to return to their traditional feeding grounds, keeping track of so many animals became increasingly important.

So… how do you tell one massive whale from another? Especially when they spend so much time under the surface of the water?

Humpback Whales have an amazing quality about their tails- every tail of a Humpback Whale is completely unique to that one individual only, as in no two Humpbacks have the same fluke pattern and shape. This corresponds to the notion of a human fingerprint!

Humpback Whale tails may have scarring, barnacles, notches and shapes that help to tell individuals apart. Natural injuries or those gained through human influence (e.g. entanglement), may show up on an animal’s tail at a point in its life, giving rise to further understanding of what has happened to the whale. The natural colour print/ pattern on the underside of the tail is consistent throughout an animal’s life, and is thus a very good tool for telling who’s who. The print may be remarkably distinct, or some patterns may be similar. Some scientists and whale-watchers have even gone as far as to pick out shapes and objects on tails, like one does when looking for shapes in clouds. This process has gone so far to the point that a Humpback Whale’s “nickname” may reflect their tail pattern!

When Humpback Whales can be told apart, citizens, scientists, whale watchers, government and other marine-based organizations can work together to compile information and sightings. When photographs are collected from sightings (with respectful viewing practices in place of course), the community can compare and contrast individuals with catalogues of “ID’s”. This process is known as Photo-Identification.

Photo-Identification can aid in telling who is coming into a geographical area, where they are sighted, and if they are a repeat guest or a new one. This also provides insight into the population numbers of Humpback Whales; if you know how to tell whales apart, you can start to work on knowing how many are present in the area.

When a new calf is brought to an area, led by its mother, photo-identification can tell us about the appearance of new calves in a year. This technique also assists us in learning which Humpbacks may travel or associate together, either rarely, or frequently.

It is clear to see that a Humpback Whale’s tail are invaluable tools in the study of this species, and Photo-Identification will likely remain a lasting tool for research, as a non-invasive and efficient method. These tails have helped to enable a population estimate of over 20,000 in the North Pacific! To be allowed to continue to recover, human-induced threats to Humpback Whales must be continually understood in order to allow this positive trend to continue (e.g. entanglement, prey pressures, climate change).

Before I finish this article, I will leave you with some Humpback Whale nicknames that are sure to brighten your day!

-“Scratchy”, “Nova”, “Phi”, “Two-Spot”.

To see an example of an ID catalogue, visit MERS or Department of Fisheries and Oceans Canada (Links in References).

Authored By: Alexa D.

Naturalist and Office Staff @ Five Star Whale Watching.


Carroll, Jackie. “What is a Whale Fluke?” Pets on Mom.com. https://animals.mom.me/whale-fluke-1241.html.

“Humpback Whale.” NOAA Fisheries. National Oceanic and Atmospheric  Administration.https://www.fisheries.noaa.gov/species/humpback-whale

“Humpback Whale.” Oceanwide Expeditions. 2020. https://oceanwide-expeditions.com/to-do/wildlife/humpback-whale.

 “MERS Humpback Whale Research.” Marine Education and Research Society. https://mersociety.org/humpback#Photo_ID (link to catalogue as well).

Walker, Matt. “The strongest whale in the world.” 29 May 2015. BBC Earth. http://www.bbc.com/earth/story/20150529-the-strongest-whale-in-the-world.  

Department of Fisheries and Oceans Canada Humpback Whale catalogue: https://dfo-mpo.gc.ca/species-especes/mammals-mammiferes/humpback-rorqual-a-bosse/photos/bcx-eng.html.

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