'Life in a Shell -
a physiologist's view of a turtle'

Author: Donald C. Jackson
Date published: 2011
Name of Publisher: Harvard University Press
ISBN: 978-0-674-05034-1

Turtles are one my my biggest interests when it comes to exotic pets, and I've been fascinated by them as long as I can remember. This title by Donald Jackon looks at how the characteristic shell impacts and benefits the life of chelonians, and is a great read from beginning to endearing epilogue. Having studied aspects of physiology, I had some understanding of the terminology used throughout the book, however each part is detailed and explained thoroughly so that it's an enjoyable read for anyone with an interest.

Layout and language
'Life in a shell' follows Jackson's fascinating career studying turtle physiology, and is written semi-scientifically to describe concepts, experiments and discoveries with glimpses of the author's personal experiences along the way. It assumes no prior knowledge of physiology (or turtles for that matter) and begins by considering the cost of life in the shell, it's benefits and disadvantages to the animal. What intially sounds like a simple but cumbersome form of protection evolves in the following chapters into an intricate structure which has aided and sculpted the turtle's biology for millions of years.

Reference is made throughout the title to current scientific terminology, although Jackson takes ample time to describe such wording for those who may be unfamiliar. The blend of scientific information and personal insight makes it an interesting read regardless of previous understanding. Whilst seasoned physiologists might find the underlying science less complex to understand, the personal comments and reasoning for Jackson's experiments may be of interest, whilst the book also provides the fundamental concepts of turtle physiology which are accessable to anyone with the time to enjoy it.

Frequent comparisons are made to human physiology (such as our ability to hold our breath compared to that of a hibernating turtle) or those of other animals, to help illustrate the differences and adaptations that have evolved in these reptiles, and give some sense of scale. It is by putting Chelonia in context of other animals and species that Jackson manages to bestow a sense of appreciation for these animals, something which in today's age of endangered species can't be praised enough.

The story of the turtle's physiology is pieced together in chapters covering the following questions:

  • Buoyancy - how does the turtle remain suspended mid-water?
  • Breathing - if the ribcage is fused to the shell and immobile, how can a turtle inhale/exhale?
  • Respiration - how can the turtle overwinter without breathing during hibernation?
  • Without oxygen - how can a turtle survive prolonged periods without oxygen?
  • The heart - is a hole in the heart an adaptation, or a flaw?
  • Metabolism - how is a turtle's metabolism affected by temperature and excercise?

    One of the fantastic things about this title is the curiosity of the author is transferred the reader. As Jackson begins by explaining his first few questions about the turtle's shell, it becomes clear that with every answer found, there is always more to be discovered. As he begins to create a bigger picture and lead you down the path of understanding how a turtle functions, you begin to realise that the shell is not simply a protective covering, but intrinsic to everything that the turtle does. From buoyancy when swimming, to breathing and respiration, hibernation and circulation; the shell has pushed these reptiles to evolve like no other, and become one of the most unique creatures on the planet.

    For anyone interested in turtles, reptile or physiology, this book is a superb read, and highly recommended.

    If you have any questions regarding this review, or require further information on this title, please contact me using the email address below:
    Paul Edmondson

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