Sea mammals and climate change (the lesson)
Most of us rarely or never get to see sea mammals, seals, whales, dolphins etc in their natural environment. But most people like them anyway. They are extreme interesting creatures, very intelligent, social, and living in a world completely different from ours.
In earlier times people have been hunting most species, up to extinction or nearly extinction in many cases. Nowadays many species are protected but not all! Protests against whale or seal hunts happen in many countries. Touristic programs giving people a chance to see them, like ‘whale watching’ tours, are popular.
Even if living far from humans, many of these animals experience the effects of our modern world, but they can also help in the fight against climate change. Find out how. Maybe you get a good idea to start a study on these fascinating animals
Read the articles about sea mammals:
Answer these questions, or divide your class in small groups and take each one of the species, answer the questions concerning them, and find more information about your species. After that make a presentation for your class.
1. Cuvier’s beaked whales can dive almost 10,000 feet (over 3 km) and hold their breath for 138 minutes. Why do they do it, or: what do you think is their main prey? Find more information about their living habits.
2. How much extra pressure do they have to survive when diving 10 000 feet?
3. What has myoglobin to do with deep diving? Find more information about the ways sea mammals can survive deep diving.
4. The article suggests that the animals are nowadays diving deeper than before. What do we humans have to do with that?
5. “Will all marine life someday be hiding in the depths of the ocean, having changed their mechanisms ...” Is it possible for mammals to change their mechanism to live in the deep permanently? Why of why not?
1. Weddell seals can also dive deep and long (600 m deep, and stay one hour under water), but they also dive deep under the sea ice. Why is that an extra problem?
2. The predator they have to fear is the Orca. Under sea ice they are safe. Find more information about the hunting tactics of Orca’s.
3. What is the difference between our GPS system and the ‘GPS’ of these animals? (Which information do they use and which do humans use?)
4. How is it possible to know your exact location based on magnetic fields? Find more information about the ‘magnetic map’ of the sea bottom – and other animals who use it too.
5. If scientists want to prove that these (and other) animals use the magnetic field, how could they do it? (With these big animals, living in the cold Antarctic, it will be very difficult, but with sea turtles this research has been done already)
6. How can this way of using magnetism possibly be useful for humans too?
1. Elephant seals live mainly in the open ocean. Once a year they come to certain spots where they breed. They stay on the beach about one month. Which possible systems can help them to find the way back?
2. Why do these animals probably use the same navigating system as the beaked whales?
3. Why are elephant seals quite well fit for carrying these tags, with no problems for the animals? Why is it not easy for the scientist to fit the tags on the seals? (Where do you find them?).
4. Why is it important to measure also water temperatures in the deep, kilometers under the surface?
5 Why is it important to know more about water temperature, salinity etc near the poles?
6. What will a warmer climate mean for these animals?
1. What are the main differences between whales and seals?
2. They have more or less the same form; this is an example of ‘convergent evolution’. What does that mean?
3. How is our modern world influencing their life?
4. What must be done to prevent their extinction?