Hibernation And Other Forms Of Dormancy (1962)

for all animals must eat in order to live but there are times when they cannot find food animals have different ways of living through such times for instance this spadefoot toad can find food only in water when the hot summer sun dries up its Pond the toad has a special way of surviving the period of drought using its horny feet the Spade foot will dig itself into the ground it will remain buried until rains come again making food available the amphibians such as the Spade foot toad conserve their energy in times of food shortage by burying themselves once they have dug a resting place they go into a very deep sleep called estation during estivation the animal's heartbeat slow and it breathes only occasionally some animals must eat more often than others to conserve energy a bat goes to deep sleep each day as night approaches the bat's twitching muscles help to bring its heartbeat and breathing back to normal complete Awakening takes several minutes then the bat is ready to fly off in search of its evening meal whether they search for food during the night or in the bright daylight many animals gather more food in summer than they need for daily living the golden mantled ground squirrel stuffs its cheek pouches with seeds to store in its burrow the winter ground squirrel eats more food than it needs the excess is stored in the body as fat reserves of fat help animals survive the food shortages of Long Cold Winters some bir Birds avoid this food scarcity by flying to warmer areas where food is more plentiful this is called migration but most animals do not migrate for example a frog May lie dormant or sleeping beneath the ice of a pond the frog is a coldblooded animal his body temperature changes with that of its surroundings heartbeat and breathing slow down gradually as the weather gets colder if the pond freezes completely the Frog May burrow into mud at the bottom where it will remain dormant until spring the fence lizard is also a coldblooded animal like many other reptiles the dormant lizard will stay in a crevice or a cave its life processes merely slowed down during winter many insects spend the winter in cracks of rocks by the time of the first snowfall most of the insects and other animals will have found a means of protecting themselves from Winter's cold beneath the loose bark of a tree some insect seek shelter although this Beetle appears dead it is only dormant we call such adaptation to periods of food shortage over wintering the spider is also dormant on this overturned Boulder is the nest of a mud darber wasp the WASP is in a resting stage it is called a pupa for many insects the winter resting stage is part of the life cycle unless exposed to Winter's cold a caterpillar cannot emerge from its cocoon as a butterfly in Spring long after other animals have taken shelter for the winter the bear is still active but soon it too will seek shelter thick layers of fat and heavy fur keep the bear warm in its den where it will doze for most of the winter the winter sleep of many other animals is similar to the Bears although the raccoon may sleep in the hollow of a tree several weeks at a time any slight disturbance will easily awaken it deep under the snow many creatures are sleeping in their Burrows some mammals such as the ground squirrel enter a special kind of winter sleep called hibernation during the long months of winter the mammal is insulated from cold by the layer of fat stored on its body the fat also supplies fuel for heat and energy this deep sleep hibernation is its way of conserving fuel when hibernating the mammal usually curls itself into a tight ball if we watch The Awakening of this ground squirrel we could learn more about hibernation at first the heartbeat increases very slightly during hibernation the heart beats only five times per minute although the normal rate may exceed 300 we will use a drum to indicate the animal's heartbeat breathing starts to increase from only one breath per minute to the normal rate of more than 150 breaths per minute as the mammal wakens its body heat increases through the quickening activity of muscles beginning first with the heart and chest body temperature is now slightly above freezing normal temperature is over 100° Fahrenheit the muscular activity and warming extend outwards from the heart and chest to the front parts of the body then later to the hind Parts as the breathing becomes faster and deeper other signs of Awakening occur the front paws begin to move the motion of the for Paws is stronger then muscles begin to move in other parts of the body the animal's nose and facial muscles begin to Twitch a slight movement of theind foot begins breathing and heart rate may even be higher than normal as the muscles work to increase body temperature finally all the muscles are active producing heat and speeding The Awakening after several hours the ground squirrel is brigh eyed and fully awake most hibernating mammals waken every few weeks if it is still cold the animal will go into a deep sleep again when spring comes animals resume their active lives beginning a new the cycles of Life which for many will include hibernation or some other form of dormancy