Enjoying whale science

kw: book reviews, nonfiction, whales, science, paleontology, natural history

Almost a year ago, I went with several colleagues from the Delaware Museum of Natural History (DNMH) to look at the skeleton of a humpback whale on the shore of Delaware Bay. It had been a juvenile whale, about 35 feet long, that washed ashore dead near a popular fishing pier. It was towed by the state Department of Natural Resources to a more sheltered spot on a wildlife refuge, to rot in peace. Here are some of the crew having a look. The skull is to the right.

We were mainly there just to see it. The director and a curator were along, though, and they decided to see if the museum could get permission to collect at least the skull. Early this year they applied for the appropriate permit, which was approved. They decided to bring the skull, several vertebrae, and a flipper if they could excavate it from the sand. A large shed was put up in the museum's back yard.

Just about a month ago a few folks went to gather it. The skull weighed about 250 pounds, so it took a few people to lift it onto a flatbed truck. Anyway, they got it safely retrieved, along with several vertebrae and the flipper they could get to. The skull was put in the shed, where I took this picture. You can see that the remaining skin, seen in the photo above, had been eroded and eaten away, leaving just the not-too-smelly bones.

This isn't stamp collecting. This skull is about as big an object as the museum is capable of storing and preparing for exhibit…and exhibiting. A new plan for the exhibit halls is in the works anyway, so they'll tinker with it to find a way to include this, possibly as a touchable piece. It will need a bit of degreasing before it is fit to touch, though! Whale bones such as these are full of fats and oils, even after more than a year in an exposed location.

Reading Spying on Whales: The Past, Present, and Future of Earth's Most Awesome Creatures, by Nick Pyenson, I learned that the Smithsonian Museum's National Museum of Natural History (NMNH) has a series of warehouses on the outskirts of Washington, DC, where research collections and other materials not on exhibit are kept. That includes thousands of whale specimens, including hundreds of skulls.

The DMNH skull is rather small compared to some. The skull of a mature blue whale can be more than 25 feet long, and each lower jaw bone weighs about a ton. It takes a lot of muscle to hold such a pair of jaw bones in place during lunge feeding, but a 100-to-150-ton animal has the muscle to do it.

Dr. Pyenson is a paleontologist at NMNH, specializing in fossil marine mammals. To understand the past of whales, he has spent a lot of time with people who work with living (or recently living, in the case of whalers) whales. He is the kind of scientist I like most, one who gets out of his stovepipe and works with others in allied, and not-so-allied, fields.

True to the title of the book, it is in thirds, for past, present and future. Whales as we know them arose rather recently, roughly 5 million years ago. Fully aquatic whales, similar in shape to modern species but smaller ("only" the size of a minivan or school bus), have been around for something like 35-45 million years. Earlier semi-aquatic "whale ancestors" date to 45-55 million years ago. The earliest "whale", called Pakicetus, was kind of like a big dog that could wade and swim. A significant portion of the author's study is aimed at finding how whales grew to the awesome sizes of the largest ones that exist today. A few species regularly exceed 80 feet in length (24m), topped by the blue whale; the largest blue whale ever measured was 109 feet (33m) long.

A tentative scenario for producing really enormous whales is the combination of a globe-girdling Southern Ocean, but a closure of the Atlantic-Pacific communication that existed until 4-5 million years ago, until the uplift of Panama. Currents and wind patterns cause localized upwellings of nutrients, which in turn cause stupendous accumulations of small prey animals such as krill and herring. Large whales migrate long distances to feed on these bountiful feasts in their seasons. A really big whale has to eat a lot. Being big, though, it can travel more efficiently than a smaller animal, so crossing the Earth to get between areas for feeding and breeding is more possible. There are other factors the author enumerates.

The author's life is at the extreme end of being a naturalist, for which he has to (gets to) travel as far as the whales do, and to all the places where whale fossils or whale remains can be found. He tells amazing stories of field seasons in Chile and Norway and Alaska. He got to try his hand at putting a suction-cup tag on a whale in Alaska. Live and learn: he broke the tagging pole, but got the tag on. Such tags stay on for just a few hours or for a few days, then slip off. Then begins the fun of locating the tag, which fortunately is sending "Here I am!" radio signals. Only then can the scientists download the data and pictures the tag has accumulated, to see what the whale has been doing. He also tells of the astonishing find of a series of four strandings that happened a few million years ago, probably caused by red tide or a similar toxic phenomenon. Dozens of complete whale skeletons were found it a special place in Chile, of sizes ranging up to 30+ feet (9+m). That is as large as whales became at that time. But a single, complete skeleton is usually the find of a lifetime. He and his colleagues were blown away to find acres and acres of them!

Whales today exist as about 80 species, from smaller dolphins and porpoises—roughly human size—through the "usual" 40-70-foot sizes we associate with sperm whales, humpback whales and gray whales, to the really big blue and finback whales. About 8-10 times as many fossil species are known.

What of the future of whales? A generation ago their future was in doubt. Already by the early 1900's, it is thought that 90% of all whales had already been caught and killed, but the catch continued until the 1970's, when a series of international laws were enacted. Some whaling still occurs (and it gave the author a chance to dissect some very fragile portions of whale anatomy). But the chapter "Shifting Baselines" reveals a great problem when a trend goes on longer than a human lifetime. The "good old days" that senior whalers now living remember actually represent a much-depleted ocean. Nobody living remembers a time like the 1600's when whales outnumbered ocean-going ships.

I remember when I was trying to get a multi-level marketing business going, and two women came to one of my presentations, apparently drawn by the "anti pollution" portion of my advertising. But they didn't want to sell my products. They really wanted to "Save the Whales." Considering that this was 1970 or so, the whales they wanted to save consisted of about 3% of the whales that once roamed the seas.

Today a few species have rebounded, but there are still probably no more than 10,000 (some say 20,000) blue whales remaining, and there may be more than one million sperm whales. As Captain Ahab could attest, they are harder to catch than a blue whale. But there were probably at least half a million blue whales 200 years ago, and several million to perhaps 10 million sperm whales. Those are just two of around 80 species.

How will climate change affect the whales? It seems that in recent years some Pacific gray whales (the only remaining gray whale species) have made their way through the Northwest Passage to the Atlantic, something not possible for the past 2-3 million years. However, human shipping is starting to take advantage of the same passage, and ship-whale collisions usually go very badly for the whale.

I could rhapsodize on and on. I really enjoyed this book.