| Hold Your Breath |
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 A Little Bit MoreMy guess is that most people assume that turtles must be “hibernating” during the winter, at least in the northern states and Canadian provinces. But it may be a complete surprise to learn that at least some of these turtles, like the Painted Turtle, are doing so without any access to oxygen for months; quite an impressive feat! The term brumation is also probably a new one to most people. Brumation refers to those reptiles that dramatically reduce or cease food intake, although they may drink a bit, in response to cold temperatures.  Painted Turtles are quite common in much of North America and have been looked at closely during the winter months to understand this phenomenon. It’s interesting to note that although older Painted Turtles brumate to avoid freezing temperatures in winter, newly hatched turtles can actually be frozen without harmful effects as long as they’re never any colder than about -8°C (18°F). Painted turtles are known to bury themselves beneath as much as three feet of mud. This insulation offers good protection from subfreezing temperatures for up to 5 months during brutal northern winters but also restricts or eliminates access to oxygen. In order to survive, Painted Turtles are able to prevent the buildup of lactic acid (this is what makes you feel tired from exercise) within their body. They accomplish this by slowing their metabolism but also by using materials stored within their shell to buffer or neutralize the lactic acid that is produced. ActivitiesScience & Math – Hold Your BreathObjectives: A clearer understanding of how a lack of oxygen feels Materials: Watch with a second hand, graph paper Our unit has focused on how reptiles, specifically Painted Turtles, can overwinter by brumating. These turtles brumate often without access to oxygen making it a very impressive feat. But no endotherms (warm-blooded) animals are able to accomplish this same feat. During hibernation of mammals like Woodchucks, their breathing rate dramatically lowers but at no time do they stop breathing for an extended period. I think it would be interesting for your students to see just how long (actually short) they can hold their own breath without breathing. Humans are not very well adapted for going without exchanging air many times a minute. Have students time their ability to hold there breath and graph what you find. You may want to pit the boys against the girls or students on one side of the room from the other. It may also be a surprise to discover that those able to hold their breath the longest, are not the ones you would have suspected. Be sure to time individuals so you can graph each person’s time. By averaging each group’s times you can then look at one group vs. another. You might also want to compare the longest held breath with the shortest or whatever to give the students some perspective, using math, on just how long humans are able to stop breathing. CAUTION : There may be an inclination for some to make fun of anyone who can’t hold their breath very long so be sure to “defuse” this possibility at the outset. There can be all kinds of factors that influence just how long someone can hold their breath. Definitionstorpor: extreme reduction in body functions Related WebsitesDownload this Poster |