ConversationDiscuss Whales' Breath: Student: Well, you know, I am writing that paper about whales and the path they travel as they swim through the ocean, their migration patterns. Professor: Yes. I remember. Student: And well, I was thinking about it and I realized I don't understand how they hold their breath underwater. It's a little crazy for me to be writing about migration patterns without actually knowing how they stay underwater for so long. Professor: Did you do any research to find out how they do it? Student: Yeah, I did. I searched on the Internet and there was a lot of information about whales, their habitats, the way they communicate, you know, their songs. But if there was anything about whales and how they hold their breath, I missed it. I've got a bunch of books. Actually, I have got so much information, it's a little overwhelming. Professor: I am surprised there is nothing about it in any of those books. Student: Well, to be honest, I've only skimmed them so far. I am still working on finding sources. Professor: OK. I know I encourage everyone in class to look at a substantial number of sources, but I don't want you to get overwhelmed. Looking at a number of sources gives you a good knowledge base, but students only have a limited amount of time to work on each paper. I don't expect you to read a dozen books on whales for this assignment. Focus on just a few. Student: Ok. Thanks. Professor: You know, since you are already here. I can give you a quick summary of how whales hold their breath underwater. It's just a matter of certain adaptations in their anatomy, specifically in their circulatory system. Student: So the blood flow is what makes the difference? Professor: Yes, and in a couple of ways. First, blood makes up a larger share of a whale's weight than in other mammals. Student: So they can store more oxygen because they have more blood? Professor: Yes, but that's only part of it. They also have a greater capacity than land animals to store oxygen in their blood. Student: So how does having more oxygen in their blood help them stay underwater longer? Professor: It's the way the whale's blood carries oxygen to the rest of its body. Whales carefully conserve their oxygen when underwater in a couple of ways. When a whale dives, its metabolic rate drops, causing its heartbeat to slow down. And the blood flow to its muscles and some of its non-vital organs, like its kidneys, is also cut off. A whale's muscles and non-vital organs are able to function without oxygen for an extended period of time. Student: I see. Well, now I can concentrate on my topic.