10/8/20161 Seasonal Behaviors Part II, sec 2

10/8/20162 Winter Hardship Many places animals must deal with winter hardships little food bitter cold Frog buried in the mud.

10/8/20163 World Travelers Many animals migrate due to scarce food because of winter or drought Migration is to move from one place to another for: Food Water Nesting grounds Whales, salmon, bats, and even chimpanzees migrate

10/8/20164 Every winter Monarch Butterflies gather in central Mexico

10/8/20165 Slowing Down Some animals deal with shortages by hibernating. Hibernation is a period of inactivity and a decrease in body temperature that some animals experience in winter. Hibernating animals survive on stored body fat! Mice, squirrels,and skunks all hibernate

10/8/20166 Estivation Winter is not the only time resources can be scarce. Many desert squirrels and mice experience a similar slow down in the heat of the summer called estivation

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8 Weird Science Snakes are normally solitary creatures, but they will often group together in underground pits while hibernating. Hundreds or even thousands of snakes may spend the winter together in these hibernaculums. Why do they do it? Perhaps there is some protection from the cold in a group. (The protection would be limited, though, because snakes are ectotherms.) Or maybe it makes fining a mate much easier in the spring.

10/8/20169 Rhythm of Life Animals do not read calendars, but they need to know when to fly south for the winter. The internal clocks that trigger them are called Biological clocks. migration

10/8/ Biological Clocks Can be based upon the: length of day Temperature

10/8/ Circadian Rhythms Some biological clocks keep track of “daily” cycles These are called circadian rhythms When animals wake up and go to sleep

10/8/ How do animals find their way? When it is time to migrate, how do animals, such as the arctic tern know?

10/8/ Short Trips Many animals, including humans use landmarks to navigate. Landmarks are fixed objects that an animal uses to find its way. Coastal line can be a landmark.

10/8/ Mental Map Bees and Pigeons have a mental map of landmarks of their home territory. Mountains, rivers, large buildings…

10/8/ Compass anyone? Some migratory birds find their way with the Earth’s Magnetic Field

10/8/ Physics Connection Earth’s core acts as a giant magnet, with magnetic north and south poles. The strength and direction of the Earth’s magnetic field varies from place to place, and many birds use this variation as a map. Some migratory birds have tiny magnetic crystals of magnetite in their heads above the nostrils. Biologists think that the crystals somehow move or stimulate nerves so that a bird knows its position!

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