Mammals

G. Causey Whittow

• Publisher: Academic Press
• Year: 2013
• Print ISBN: 9780127476025
• eBook ISBN: 9781483257617
• Topic: Biological Sciences
• Subtopic: Zoology
• Index: Biological Sciences

Mammals aims to present separate accounts of the means by which each of the major groups of animals regulates its body temperature, heat production, and heat loss. Readers who wish to obtain information on thermoregulatory processes in different species will welcome this as a convenient reference work. It is hoped that the treatise will have more than convenience value. This volume comprises five chapters, with the first focusing on rodents. It discusses the thermal environment of rodents, thermal behavior, and precision of homeothermy. Chapter 2 focuses on carnivores and discusses general thermal defenses, protection against hypothermia and hyperthermia, and cold acclimation. Chapter 3 deals with body temperature, behavioral thermoregulation, and food and water intake of ungulates. Chapter 4 focuses on primates and discusses normal thermoregulation in the monkey, fever and other responses to pyrogens, and neurochemical control mechanisms in the hypothalamus. Finally, Chapter 5 discusses man's energy exchanges related to temperature and work, behavioral versus physiological temperature regulation, and a mathematical model of man's thermoregulatory system. This book will be of interest to practitioners in the fields of physiology, epidemiology, biology, neuropsychology, and public health.

CONTENTS OF VOLUME I

Aquatic Invertebrates

F. JOHN VERNBERG AND WINONA B. VERNBERG

Terrestrial Invertebrates

J. L. CLOUDSLEY-THOMPSON

Fish

F. E. J. FRY AND P. W. HOCHACHKA

Amphibia

BAYARD H. BRATTSTROM

Reptiles

JAMES R. TEMPLETON

Birds

WILLIAM R. DAWSON AND JACK W. HUDSON

AUTHOR INDEX–SUBJECT INDEX

Chapter 1

RODENTS^*

J.S. Hart

Publisher Summary

This chapter discusses the thermal environments of rodents. The rodents as a group consist of thermally sensitive animals of small body weight, which inhabit all regions of the earth from the tropics to polar region and from sea level to high-mountain climates. In arctic and subarctic climates, small animals are insulated from extreme conditions by their behavior in seeking warm microclimates, but these climates still appear to impose considerable metabolic burden particularly during foraging where subfreezing conditions are encountered. In cold climates, it is abundantly clear that the animals are exposed to much lower temperatures than in warm climates, in spite of behavioral tendencies tending to offset environmental influences. Studies on behavioral tendencies—such as huddling, nest building, and temperature selection—have shown the effectiveness of temperature compensation by this means and the seasonal variation in these qualities. The ability to tolerate elevations in body temperature in the heat and depression of body temperature in the cold is adaptive to variable conditions of environment, particularly in hot arid regions. Variability of body temperature is a mechanism for conserving energy and water. Examination of the effect of activity on temperature regulation shows that many rodents tend to increase activity with a fall in temperature and to reduce it greatly in extreme cold.

I. Introduction

II. Thermal Environment of Rodents

A. Arctic and Subarctic Regions

B. Cool Temperate Regions

C. Desert and Warm Climates

D. Special Environments

III. Thermal Behavior

A. Huddling and Nesting

B. Temperature Selection

C. Heat Reinforcement Behavior

IV. Precision of Homeothermy

A. Periodic Variations in Body Temperature

B. Body Temperature in Relation to Ambient Temperature

C. Body Temperature and Climate

V. Temperature Regulation in Cold Environments

A. Minimal Metabolism and Body Size

B. Newton’s Law, Critical Temperature, and Critical Gradient

C. Heat Production and Loss below Thermal Neutrality

D. Influence of Diet

E. Thermal Conductance

F. Thermal Limits

VI. Temperature Regulation in Warm Environments

A. Heat Production and Body Temperature

B. Partition of Sensible and Evaporative Heat Loss

C. Components of Pulmocutaneous Loss

D. Peripheral Heat Loss and Blood Flow

E. Acclimation to Heat

F. Thermal Limits

G. Heat Death and Tissue Injury

VII. Activity and Temperature Regulation

A. Amount of Activity at Different Temperatures

B. Effect of Activity on Body Temperature

C. Effect of Activity on Oxygen Consumption

D. Activity and Cold Resistance

E. Diurnal Metabolic Rhythms

VIII. Altitude, Hypoxia, and Temperature Regulation

A. Acute Effects

B. Chronic States

IX. Sex Differences in Temperature Regulation

X. Summary and Conclusions

References

I Introduction

The study of temperature regulation has been pursued more intensively in the rodents than in any other group during the last 25 years, particularly during the last decade. This interest has stemmed partly from the convenience in methodology for study of animals of small body size (10¹−10⁴ gm) but primarily from the great diversity in regulatory responses within the group. The latter aspect has attracted much attention from the comparative physiologists interested in hibernation, and in behavioral and physiological regulations during active states in relation to the great diversity of ecological and climatic conditions. These studies have shown that it has not been possible to understand the regulations in different species without knowledge of microclimatic conditions of their habitats and of the behavioral features of the species in question. While the characteristics of torpidity and hibernation will not be considered in this chapter, the microhabitat conditions and behavioral aspects of rodents will be analyzed, since these aspects are an important component of the total ability of a species to insulate itself from its environment.

While it may be concluded that the major interest of the zoological interpretation of temperature regulation has been in relation to the behavior of animals in nature, the rodents have been of primary interest to physiologists in the interpretation and understanding of the mechanisms of temperature regulation. Much of the work in this area has been on laboratory animals such as the wh...

Table of contents

• Cover image
• Title page
• Table of Contents
• CONTRIBUTORS
• Copyright
• LIST OF CONTRIBUTORS
• PREFACE
• CONTENTS OF VOLUME I
• Chapter 1: RODENTS
• Chapter 2: CARNIVORES
• Chapter 3: UNGULATES
• Chapter 4: PRIMATES
• Chapter 5: MAN
• AUTHOR INDEX
• SUBJECT INDEX