How are physical characteristics combined with behavioral characteristics by northern mammals to conserve heat during extreme periods?
http://en.wikipedia.org/wiki/Hibernation
http://en.wikipedia.org/wiki/Estivation
In addition to the excellent information posted by Lance, you may also find this site useful.
http://www.barentsinfo.org/?deptid=14761
To understand how northern mammals conserve heat during extreme periods, it is important to know about two biological processes: hibernation and estivation.
Hibernation is a state of deep sleep that animals enter during the winter to conserve energy. It is associated with colder temperatures and reduced food availability. During hibernation, an animal's physical and behavioral characteristics work together to help them conserve heat.
Physically, northern mammals have adaptations such as a thick layer of insulating fat, dense fur or feathers, and reduced blood flow to peripheral organs. These characteristics help in reducing heat loss by insulating the body and conserving energy.
Behaviorally, hibernating animals lower their metabolism, heart rate, and respiration rate, which helps them conserve energy and maintain their body temperature at lower levels. They also seek shelter in protected areas such as burrows or caves, which provide additional insulation from the external cold.
Estivation, on the other hand, is a similar process that occurs during periods of extreme heat. It is often observed in animals living in desert or arid environments. Estivation allows animals to survive and conserve water during dry and hot conditions.
During estivation, animals adapt both physically and behaviorally. Physically, they may have adaptations such as a thick, water-resistant skin or scales, reduced water loss through specialized body structures like thickened skin or nasal passages, and the ability to store water inside their bodies.
Behaviorally, estivating animals limit their activity during the hottest parts of the day, seek shelter in cool and shaded areas, and may also lower their metabolic rate to conserve energy and water.
To further explore the topic and gain a deeper understanding, you can refer to the provided links:
- Wikipedia articles on hibernation (http://en.wikipedia.org/wiki/Hibernation) and estivation (http://en.wikipedia.org/wiki/Estivation).
- The BarentsInfo website (http://www.barentsinfo.org/?deptid=14761) may also have relevant information for your research.