A Lesson Plan

This lesson plan is designed for high school and middle school science and social studies teachers. It provides information about scientific discoveries, environmental issues, and legislation. It also includes links for additional resources about whales and dolphins and a dolphin quiz. This lesson plan is written by the author of "The Dolphins' View," who has been a substitute teacher in Albany and in Berkeley, California. During your lecture, any mention of "The Dolphins' View" story or our website www.thedolphinsview.com will be appreciated.

"Class, we're going to talk about whales and dolphins today, mostly dolphins. For starters, how many species of dolphins can you identify?"

Students raise hands. Write their responses on the board.

"Very good, you've identified x species. There are actually 35 species of dolphins, including 5 species of river dolphins. There are also 6 species of porpoises. Generally, dolphins are larger and more streamlined; porpoises are shorter and stockier. Dolphins have larger and falcate ('hooked') dorsal fins, whereas porpoises have either triangular dorsal fins (without a curve), or no dorsal fin at all (in the case of the Finless Porpoise). Furthermore, most dolphins have a 'beak', while porpoises are 'beakless', with a rounded snout. Porpoises travel in smaller groups than dolphins and are less acrobatic at the surface."

resource: link to dolphin species page, link to return

"Can anyone identify the largest species of dolphin?"

"That's right, the orca, or killer whale, is classified as the largest species in the dolphin family.

"Now, let's discuss dolphins; how they’re different from us, how we treat them, the environmental hazards they face, why some are endangered and why some are captive.

"First, let's take a quiz. Who has the smallest brain: an elephant, a bottlenose dolphin, man, or a sperm whale?"

Students raise hands.

"The answer is man. An elephant has a bigger brain but its not as complex with folds and convolutions like man. A bottlenose dolphin’s brain has similar though different complexity and its 25% larger than man. The biggest brain in the known universe belongs to the sperm whale – 7 times larger than man…Man has the largest ratio of brain to body weight, the bottlenose dolphin is second, chimps third. So, what is intelligence anyway? Is it strictly brain size? Does it measure how well an animal is suited to its environment? We can’t even measure intelligence in our own species. How can we measure it in an animal that lives in a totally different environment?

"Let’s think about how dolphins are different from us. They live in a totally different world, an alien world. Imagine what it would be like to live in the sea and never come on land. For one thing, sound travels five times faster in water than it does on land. Living in the ocean is not only more three dimensional, but its also a world of sound. Land would also be an alien world to dolphins. If you wonder what it would be like for a dolphin to live on land, read "The Dolphins’ View," or visit www.thedolphinsview.com.

"Their senses are different. They can see as well as we can, but their primary senses are acoustic. So much so, that they "see" with their sonic senses. They don’t even receive most sounds through their ears. Dolphins don’t have any hands either. So, they can’t make tools. They’re smart enough to use tools, but they can’t make them.

"What else is different? How about their culture? They have no fathers. Well, biologically, they do, but culturally, they don’t. Their culture and their society are far different than ours. Our primary bond is between a man and a woman. Theirs is between a mother and her calf. They have no ‘husbands’. Males hang out with males; females with females and calves. They can’t go to the grocery store to get food either. They’re dependent on each other to hunt for food and protect each other from predators.

" All these things are obvious or well known about dolphins. But there are a lot of things we don’t know about them. Scientists have uncovered some of their secrets, but not all of them. Aristotle was the first to record that dolphins were different than fish, that they bear their young alive and suckle them, breathe air, and make underwater sounds. He noted their voices in air too, though they don’t have vocal cords, but 19th and 20th century biologists scorned his observation as mythology until the 1950s. There was a long, dark period for about two thousand years.

" It wasn't until the 18 century that Linnaeus, a Swedish botanist, classified dolphins in the mammal family as cetaceans, not as fish. From that point, science advanced slowly, partly because dolphins are difficult to study and partly because people were more interested in whales, which were considered a natural resource. As long as the supply lasted, there wasn't an incentive to study them.

" It wasn't until whale populations declined, before and after World War II, that scientists started studying dolphins. In 1936, James Gray, a Cambridge scientist, wondered how dolphins could travel through water at up to 40 kilometers (25 miles) an hour. He performed tests with rigid models of a streamlined dolphin body and calculated that it was theoretically impossible for dolphins to attain such speeds because the energy required was 7 to 10 times greater than what their muscles could produce.

"He proposed two possible solutions to this 'paradox': either their muscles were able to generate much more energy than the muscles of other animals or they were able to reduce the friction drag of water as it passed over their bodies. Professor Gray concluded: 'Nature's design for a dolphin is much more efficient than any submarine or torpedo yet produced by man'. This was an important finding because water adheres and forms eddies on a ship's skin, slowing its passage through water, and naval architects are always looking for ways to reduce drag.

"In 1938, a German researcher, Max Kramer, patented a 'Device for the Reduction of Friction Drag', which involved a method of reducing the turbulence caused by the flow of water over a battleship or air over a missile. The Second World War halted his work, but after the war he went to America, and saw dolphins for the first time when he crossed the ocean. Kramer was fascinated by their swift, graceful swimming and decided to learn more about them.

"In 1955, Kramer examined dolphin skin under a microscope - and found that their outer skin consists of a soft, waterlogged coating on a hard, fatty inner skin. So, every tiny oscillation in the water on any part of a dolphin’s body's surface is adjusted automatically. Kramer announced that he had discovered 'a highly refined realization of the basic idea' of his 1938 patent. Tests with simulated models proved that this design reduced surface drag by as much as 60 per cent!

"In later research, scientists found that dolphins have unusually large surface skin cells that slough off easily. British researchers theorized that their skin cells slide away and shed the very surface that causes drag. Eventually, scientists concluded that the attachment of their upper skin to lower skin and of their whole skin to their blubber gives their surface some of the physical characteristics of a liquid. So when dolphins swim, water flows over their body at the same speed as water farther away, reducing drag, giving them laminar flow.

"Let’s stop a moment to consider what this means. It means that dolphins have adapted to their environment in a manner that allows them to swim faster than muscle power alone would allow. Isn’t that amazing?

"Now, let’s switch gears for a moment. Presumably, you all know that dolphins are believed to have evolved from land animals. How would scientists have determined that?"

Students raise their hands.

"Yes, from the fossil record. "What land animals do you think dolphins evolved from and how do you think scientists figured it out?

" In 1950, Alan Boyden and Douglas Gemeroy from Rutgers University compared blood proteins of cetaceans to other mammal groups and found them most similar to artiodactyls and ungulates, hoofed animals, like goats, cattle and hippos. That’s how they determined that dolphins evolved from ungulates."

"Moving on, you may wonder how scientists figured out that dolphins use sonar. Aristotle was the first to note that dolphins have the power of hearing, with no external ears (which would reduce their streamlining and slow them down). In 1947, Arthur McBride, the first curator of Marine Studios, recorded observations suggesting that dolphins might have sonar. In the early 1950's, Winthrop Kellogg of Florida State and, independently, William Schevill and Barbara Lawrence of Woods Hole, presented experimental evidence that dolphins navigate and locate objects by sonar. Ken Norris proved it conclusively in 1960 when he demonstrated that a dolphin, wearing soft rubber suction cups over its eyes, could navigate through a maze of pipes in a tank. Ken Norris also discovered that the primary receptor of sound for dolphins is not their ears, which are pinholes on the side of their head, but their lower jaw."

Note, more information about dolphins, such as how they can live in cold water and not get hypothermia and how they get fresh water in a salt-water environment, can be found inside "The Dolphin’s View." Reference information, as well as information about dolphins, tuna, and the Marine Mammal Protection Act, can also be found in the "Dolphin History" section of this website. Teachers, who follow a "pure" science model, may object to the next three paragraphs. However, the issue of animal rights is becoming more prominent and your students may be interested in this perspective.

"There are lots of things scientists don’t know about dolphins too. I’m going to put away my pure science hat now and discuss a few issues from an anthropomorphic perspective. Anthropomorphizing is attributing human form or personality to animals. Mickey Mouse is the most famous example. Pure scientists are highly critical of anthropomorphizing. For example, pure scientists don’t think dolphins have a language. They will admit dolphins have a far greater frequency range of sound than humans do (greater than any animal except the bat), but unless it can be conclusively proven, they will deny dolphins have a language. (Teacher note about language - see Louis Herman’s research with hand signals in the History section). So, if you want a challenge for a professional career, try becoming a dolphin translator.

"How many of you have a dog? What have you noticed about their caninality? I used to have 2 dogs from the same litter and I was amazed how different they were. Dolphins aren’t simply "animals" either. They have unique dolphinalities. Let’s explore that notion for a minute.

"Our perception of dolphins and all other animals is quite limited because we only look at them from a human point of view. Most people don’t know dolphins have bigger brains than people do, so they don’t think dolphins are as intelligent. They hear dolphin songs but they don’t think dolphins can communicate. Scientists have observed the bond between a dolphin mother and calf, but people don’t think dolphins can love. Fishermen have seen dolphins supporting a disabled member of their pod, holding him above the water with their backs so he can breathe but most people don’t think dolphins feel grief. Boaters see dolphins riding a bow wave and people see dolphins reaching for the sky, breaching above the waves. Do they think dolphins know joy?"

Note, some of the descriptions in the following section are graphic. Modify them for the maturity of your class. Some teachers may also object to the animal rights perspective in the closing section and may not want to discuss it with their class. However, teachers should be cognizant of this issue and I encourage you to read it.

"Let’s stop anthropomorphizing now, and focus on environmental issues that affect both dolphins and their larger cousins, whales. Let’s start with the California gray whale because they recovered from the brink of extinction twice. People used to slaughter them with explosive harpoons, now they pet gray whales from rubber boats in Baja. Other species haven’t fared as well. The oceans were home to thriving populations of whales and dolphins before man decimated their populations for lamp oil, pet food, and sport. In 1900 there were 250,000 blue whales. One hundred years later, the largest animal ever to live on the planet was reduced to a struggling population of 3,000. The story is the same for other whales: right whales. Bowhead, blue, fin, sei, humpback, and sperm whales are all listed as endangered or vulnerable by the World Conservation Union, the Convention on International Trade in Endangered Species (CITES), and the U.S. Endangered Species Act (ESA).

"Japan and Norway continue to persuade the International Whaling Commission (IWC) to allow them to continue hunting whales under the thin veil of "scientific research." Iceland just started too. Iceland wants it both ways – they want the whale watching business and the whale killing business. Presumably, if the IWC forbid ‘scientific research’ these nations would defy international opinion and do it anyway.

"Now what environmental factors have endangered some species of whales and dolphins? Over fishing is a big factor, habitat destruction, drowning in fishing nets and other debris, bycatch, and illegal hunting all contribute to depleted populations of wild dolphins.

"All creatures need food, air, water, and other environmental factors composing their habitat. When people build beachfront housing, bridges, docks, and harbors, they take over areas that belonged to ocean life. As human population increases, more speedboats, water skiers, and jet skiers take over parts of the ocean where dolphins live, upsetting their patterns of hunting, sleeping, and reproduction. That, plus taking so many fish that they can’t reproduce and replenish their stock so dolphins don’t have any to eat, is habitat destruction.

"Let’s talk about ‘bycatch’ and illegal hunting too. Bycatch is the unintentional capture of sea life in commercial fishing nets. Victims include sea turtles, birds, dolphins, juvenile fish, squid, and other animals. To make matters worse, it’s extremely wasteful because the unintended animals caught, which are usually dead, are thrown away. Illegal hunting doesn’t happen that much in the United States anymore, but it happens more often in other countries, especially Japan. Sometimes it’s for sport, but most commonly some fishermen have the idea that dolphins are taking ‘their’ fish and they shoot dolphins.

"Then there’s pollution. PCBs are one of the lethal forms of pollution, which may have contributed to the dolphin holocaust. When toxic chemicals enter streams and rivers on their way to the sea, they contaminate fish and crabs and other animals. Farther up the food chain, when we eat them, the toxins concentrate in our bodies and we get tumors… You know people think the white beluga whale is so cute, but their bodies are so full of PCBs, that when they die in the Saint Lawrence River, the Canadian government considers them toxic waste.

"The latest threat, is low frequency active sonar (LFAS). Seems like the U.S. Navy wants to get into the whale and dolphin killing business too! I guess nobody told the Navy the Cold War is over and we won. Maybe they think that terrorists have submarines. In any event, the Navy wants to use LFAS to detect silent submarines but its transmitted at very high decibel levels and travels over long distances. For people, the noise level would be like standing 20 feet away from a space shuttle launch rocket at takeoff. For dolphins and whales, it can destroy their hearing, their greatest and most sensitive sense. Without it they’re blind, they become disoriented, vulnerable to predators, and we find their bodies stranded on the beach.

"Dolphins don’t just get slaughtered for tuna fish or cat food. Some countries do it for sport. Japan and the Faeroe Islands (a province of Denmark) kill thousands of dolphins a year; so do Chile, Peru, and Venezuela. In Japan, the ocean turns red with dolphin blood. Dolphins are driven into the shallows. They pitch and roll, jammed and trapped in shallow waters, quivering in freight, whistling in distress. Then a hook is sliced into their side, they’re winched ashore, and their bodies are slashed. Witnesses have seen their hearts torn out and tossed on the beach…still beating.

"Dolphins get captured too – their homes invaded, their families torn apart. Then they’re transported thousands of miles to jail – concrete tanks called aquariums for the amusement of people. Somebody tell me, what crime did they commit?

"Cuba, Japan, Russia, and Mexico were the most prominent countries capturing dolphins for slaves. At least they were until July 2003, when the Solomon Islands got into the act with a massive capture – 178 dolphins will never feel the tides, swim in a straight line as far as they want, capture their own prey, dive deep into the depths, ride the surf, feel all the joy of being a wild dolphin.

" If people realized the huge price the dolphin pays to entertain them, would they still get pleasure watching a captive dolphin breach through a hoop? How about the latest craze, riding on a dolphin? People don’t realize when they visit marine parks that they’re endorsing slavery.

Note: Marine parks tell people they’re providing a humane service because their dolphins couldn’t survive in the wild. I fell for their story too, especially at the Dolphin Research Center (DRC) in the Florida Keys, which claimed to represent the best interest of dolphins. Then, researching on the Internet, I discovered that DRC participated in the dolphin slave trade too. DRC continually maintained denial until I backed them into a corner and they couldn’t deny that the Marine Mammal Inventory Report published by NOAA proves that they ‘transferred’ a dolphin to Conneyland in Switzerland. Conneyland combined a marine park with a disco. The dolphins were exposed to loud music and night-lights, disturbing their normal communication and sleep patterns, and that’s supposed to be in the best interest of the dolphin?

"Most people don’t think about these issues. People are culturally conditioned to think dolphins want to play with them. Marine parks are supposed to educate the public about us, but instead they miseducate the public to think dolphins are their toys or playthings, perpetuating myths. People don’t think of dolphins as wild and free. They don’t look beyond the concrete walls. They don’t see the jail. They don’t see the harassment, the kidnapping, tearing apart their communities, withholding fish to "train" them. They don’t see any of that because they never think about the animal’s point of view.

"In some cases miseducation by the captive dolphin industry is half-truth or an outright lie. Some dolphins, especially those captured in the wild can be untrained to survive again in the wild. Ric O’Barry has done it. Ric trained Flipper for the TV series but when Flipper died in his arms he couldn’t train dolphins anymore. He founded Dolphin Project to free captive dolphins. Some other organizations that care about dolphins include Earth Island, Ocean Conservancy, and Natural Resources Defense Council.

"Now that you have a sense of what dolphins are exposed to, let’s think what it would be called if people were exposed to these crimes. How about murder, abduction, terrorism, genocide, extinction? Do we want that to be our legacy? If not, we need to address the great void, the lack of stewardship of the oceans.

"The vaquita, baiji, Indus and Ganges susu, boto, franciscana, tucuxi, and Hector’s dolphin (especially the subspecies Maui’s dolphin) are all listed as endangered or vulnerable by the World Conservation Union and the U.S. Endangered Species Act (ESA). Populations of Atlantic humpbacked and Indo-Pacific humpbacked dolphins are also unknown and depleted.

"A lot of people are fascinated with dolphins and a lot of kids want to become dolphin trainers. So this is my message. Don’t be a dolphin trainer. Be a dolphin savior. Work to keep wild animals wild. Work to protect their habitat, their ecosystem, and the environment we all share. And if you do that, you will not only save them, but you will also save yourselves."

Note: For more information, see Endangered Dolphins on my website. There is also a dolphin quiz on this website.