Creature Feature: Minke Whale Balaenoptera acutorostrata

Breaching minke whale Image by Jared Towers

(revised) Creature Feature: Minke Whale Balaenoptera acutorostrata

The Salish Sea is home to hundreds of amazing critters, including eight species of whales. In a sea where orcas, grey and humpback whales tend to snag all the glory, there is a lesser known whale that quietly lives its life with little hype.

This cool creature deserves a feature! Strap in and get ready learn more about this super sleek member of the cetacean nation, the… *drumroll* … minke whale (Balaenoptera acutorostrata).

Wee whales

Can you find the two blowholes on this minke coming up to breathe? Photo courtesy of NOAA

Minke whales (pronounced mink-ee) may be quite solitary and keep a low profile, but they are actually the world’s most abundant baleen, or filter-feeding whales. You can spy them throughout the world ocean. They are around the same size of an adult orca whale at about 35 feet long and 20,000 pounds. Basically, they are almost the length of a school bus and weigh as much as a 1,000 large watermelons! They are already six feet long at birth. Despite being the size of, well, a whale, they are actually the smallest member of the Balaenopterid whales which include blue, fin, sei, Bryde’s, Antarctic minke, Omura’s, and the newly-discovered Rice’s whales, to name a few. The only baleen whale smaller than the minke is the pygmy right whale, which lives in the southern hemisphere. What they lack in size, they make up for in speed. Minkes can travel at up to 25 knots (almost 29 miles or 46 km per hour)

Stinky Minke

Baleen whales have two blowholes (toothed whales, like dolphins, have only one). When they dive, they can hold their breath for nearly 15 minutes! How long can you hold yours? When they finally surface and exhale, their spout can shoot nearly 10 feet into their air. Do they really stink? Yes. If you had their diet of mostly forage fish, like capelin, herring, and sand lance, with euphausids and krill on the side, we’d be able to smell you from downwind, too! Yes, you can sometimes smell the stinky minke before you see it, which coined their nickname, “stinky minkes.” Poor things need some breath mints (JK, don’t ever feed wildlife - it’s unhealthy for them and dangerous for you! Not that a minke would take your mint, no matter how subtle your hint).

The view you will most often see of this beautiful baleen whale. Image by Barbara LaCorte, NOAA Photo Library

Big mistake: small whale

It was a Norwegian novice whaling spotter named Meincke who inspired the name “Minke whale” for our whaley good friend. While looking for whales to hunt, he accidentally mistook a minke whale for a blue whale (the largest animal on Earth!), and his crew made sure that he never lived it down. The scientific name of the minke whale translates to “winged whale” (Balaenoptera) “sharp snout” (acutorostrata), which is accurate enough. Meincke wasn’t too far off, though, this tiny whale does share the same genus as the blue whale, Balaenoptera musculus, just on the opposite end of the size spectrum. What do you suppose it means to share the same genus?

Tooth and nail

Baleen whales have bristly plates on their upper jaws that help them filter food out of water. If you have ever seen the movie Finding Nemo and watched the scene where Marlin and Dory get swept up by the humpback whale, then you have seen an animated, close-and-personal view of baleen! Baleen looks a bit like hair, and it is actually made of keratin, which is the same protein that we have in our hair and nails. Looks like we aren’t so different after all! Hundreds of these fuzzy plates are aligned and overlapped in the whale’s mouth (much like how some window blinds overlap when closed), which means prey get caught and trapped when filtered through the 230-360 cream-colored plates. 

Taking a big bite of ocean and hoping for fish! Baleen, like a long-bristled brush, traps tiny fish and plankton as a humpback whale squishes seawater out of its mouth. Minkes have baleen that does the same job. Photo by Dr. Brandon Southall, NMFS/OPR, NOAA Photo Library.

Chemical clues in keratin

Scientists are actually finding that the chemicals in keratin that make baleen can now be tested to reveal details about the whales’ life. It’s like a hidden treasure map! By reading these chemical clues, nature-detective scientists can determine a whale’s health, where it has lived, what it has been eating, and if females have reproduced or not. I wonder if our hair and nails have chemicals from the food we eat, water we drink, air we breath. What would your keratin reveal? Think twice before you eat those Cheetos.

Fast food

Minke feeding on sand lance Image by Jared Towers

When minke whales go to capture food (like krill, plankton, and small, schooling fish), they lunge on their sides and open their large mouths to engulf prey and water. They have around 50-70 pleats on their throat that expand to hold as much water and food as possible. When they close their mouths, they squish out the gulped seawater through their baleen, water out, prey in. No toothpick required- they just slurp off the food from the plates (baleen plates) with their giant tongues! Easy, right?

Here in the Salish Sea minke whales select very specific habitats. They prefer shallow banks and the areas adjacent to them with strong currents. What do you suppose attracts them to these shallow sites?

Boing calls

What does the minke say? You know those door stops that have a rubber bit attached to a spring and if you twang them they go, boioioioinnnnngggg? According to minke whale biologist, Jared Towers, that’s what their calls are like. And apparently there are two kinds of boing calls in the north Pacific, indicating two distinct populations or maybe even subspecies of minke whales. Scientists use boing detectors to listen for minke calls. But they don’t just boing. When they are not boinging they sweep. Yes, you need to shift to a sweep detector to pick up sweep calls.

Minke whale harpooned by whalers lowered onto a pier in Seattle about 1940. Most countries stopped whaling after a world-wide moratorium (shut down) of whaling was encouraged in 1986. Japan, Norway, and South Korea are still whaling, taking several hundred minke whales each per year, including pregnant females.

Photo by Howard Langrud, NOAA Photo Library

Still whaling?

Minke whales were under siege in the early and mid-1900’s as whalers hunted them without regulations. Due to their small size, however, they were not hunted nearly as much as their other baleen friends, such as humpbacks, blue, or especially right whales (right whales were so named because they were the right whale to hunt!) Their fat was rendered for oil lamps and light house lights, and their baleen was used for hair combs and corsets. Fortunately, these days minke whales are protected, mostly. A few countries in the world still hunt them for cultural, food, or research purposes. Their populations are doing well and are quite stable, but oil spills, vessel strikes, fishing entanglements, and modern hunting have depleted their populations.

Currently there are about 478 minke whales in the Washington, Oregon, California stock and around 388 in BC, based on ship-based, line-transect surveys. Would you like to spot and count whales from a ship?

Whale helpers

If you ever see a whale in need of help from being entangled in plastics, abandoned, or injured, be sure to keep your space from the whale and call the NOAA Fisheries Entanglement Reporting Hotline at 1-877-SOS-WHAL or 1-877-767-9425.

Want to learn more about Salish Sea minkes? Listen to this past presentation by Jared Towers at https://www.youtube.com/watch?v=wswccUwzF8A