H. Hewer - Collins New Naturalist Library

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William Collins

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First published 1974

This eBook edition published by William Collins in 2019

© H. R. Hewer 1974 The author asserts his moral rights to be identified as the author of this work

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Source ISBN 9780007311118

Ebook Edition © FEBRUARY 2019 ISBN: 9780007406463

Version: 2019-02-13

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Page numbers taken from the following print edition: ISBN 9780007311118

EDITORS:

Margaret Davies C.B.E. M.A. Ph.D.

Sir Julian Huxley F.R.S. M.A. D.Sc.

John Gilmour M.A. V.M.H.

Kenneth Mellanby C.B.E. Sc.D.

PHOTOGRAPHIC EDITOR:

Eric Hosking F.R.P.S.

The aim of this series is to interest the general reader in the wild life of Britain by recapturing the inquiring spirit of the old naturalists. The Editors believe that the natural pride of the British public in the native fauna and flora, to which must be added concern for their conservation, is best fostered by maintaining a high standard of accuracy combined with clarity of exposition in presenting the results of modern scientific research.

COVER

TITLE PAGE

COPYRIGHT

NOTE TO READERS

PLATES

FIGURES

EDITORS’ PREFACE

AUTHOR’S PREFACE

1. The Pinnipedia

2. The grey seal – introductory

3. The grey seal – age determination, longevity and maturity

4. The grey seal – reproduction

5. The grey seal – annual moult and spring behaviour

6. The grey seal – feeding and food; pre-breeding assemblages

7. The grey seal – the breeding rookery: cow and pup

8. The grey seal – the breeding rookery: bulls, territory and mating

9. The grey seal – moulters, dispersal, marking experiments and later movements

10. The grey seal – population dynamics, mortality and pregnancy rates

11. The common seal – introductory

12. The common seal – reproduction, pup, moulting, food and numbers

13. Other species of pinnipede

14. Conservation of British seals

PICTURE SECTION

APPENDICES: A Classification of Pinnipedia

B Breeding rookeries of grey seals

C Life-tables for grey seal cows and bulls

D Farne Island seal counts, 1956–1968

E Research and world conservation of seals

FOOTNOTES

BIBLIOGRAPHY

INDEX

ACKNOWLEDGEMENTS

ABOUT THE PUBLISHER

1. Fur-seals fanning themselves ( C. Bertram )

Head of grey seal

Head of Californian sea-lion

2. Porth Laoug, Ramsey Island, Pembrokeshire

Beach on Eilean nan Ron, Oronsay, Inner Hebrides

3. Shell-sand beach and herd of grey seals, Shillay, Outer Hebrides

Breeding rookery in wallows, Shillay, Outer Hebrides ( R. Atkinson )

4. Breeding rookery in central Fianuis, North Rona ( J. M. Boyd )

Ring-marking a moulter, North Rona ( J. M. Boyd )

5. Shore rookery, Muckle Greenholm, Orkney ( J. Woolston )

Breeding rookery, Staple Island (and Brownsman), Farne Islands ( J. C. Coulson )

6. Aerial view of Gasker, Outer Hebrides ( W. St. C. Reid in Boyd, J. M. 1957 )

Bull and cow grey seals at wallow, North Rona

7. Territorial grey seal bull, Brownsman, Farne Islands

Breeding grey seal cow, Brownsman, Farne Islands

8. Longitudinal section of root of canine tooth of grey seal

Two canine teeth from 1st year grey seals

Two adult canine teeth (bull and cow) grey seals

Cement layers in tooth of 8-year-old grey seal

Cement layers in tooth of 18-year-old grey seal

9. Section of immature testis of grey seal

Section of mature but resting testis of grey seal

Sections of mature and active testes of grey seal

10. Section of immature epididymis of grey seal

Section of mature but resting epididymis of grey seal

Section of mature and active epididymis of grey seal

Abdominal testis in ‘82-day’ foetus grey seal

11. Section of ovary with developing oocytes, grey seal

Right and left ovaries in section, grey seal

12. Free blastocyst in utero, grey seal ( R.Cox )

Young embryo ( c. 31 days), grey seal

Early foetus ( c. 55 days) in utero, grey seal

13. Early male foetus ( c. 62 days), grey seal

Young male foetus ( c. 72 days), grey seal

Later male foetus ( c. 113 days), grey seal

14. Moulting haul-out at Aber Foel Fawr, Ramsey Island

Closer view of the moulting haul-out at Aber Foel Fawr ( K. M. Backhouse )

15. Two types of moulting grey seal pups, Ramsey Island

16. Newly-landed grey seal bull, shell-sand beach, Shillay

Grey seal cow giving birth, Farne Islands ( W. N. Bonner )

17. Newly-born grey seal pup, Ramsey Island

Grey seal pup with erupting teeth, Ramsey Island

18. Grey seal cow identifying her pup by smell, Ramsey Island

Grey seal cow attacking pup not her own, Shillay

19. Grey seal pup suckling, Farne Islands

14-day-old grey seal pup, Ghaoidmeal, Inner Hebrides

20. Grey seal pup in typical early moult, Scroby Sands, Norfolk ( J. Woolston )

Grey seal bull moulter, Ramsey Island

21. Two grey seal bulls contesting territory, North Rona

Grey seals in copulation, Farne Islands ( J. C. Coulson )

22. Branded grey seal cow, Farne Islands ( J. C. Coulson )

Grey seals hauled-out on West Hoyle Bank, Cheshire ( J. C Gittins )

23. Common seal cow and pup, the Wash ( W. N. Bonner )

Two common seals (heads), the Wash ( W. N. Bonner )

24. Common seals hauled-out on sandbank, the Wash ( W. Vaughan )

Common seal bull ‘salmon-leaping’, Mousa, Shetland

1. External features of seal and sea-lion

2. Limb-bones of seal and fur-seal

3. Skulls of seals (grey and common) and of sea-lion

4. Side view of pinnipede body

5. Bradycardia in seal, porpoise and manatee

6. Kidneys and posterior vena cava in seals

7. World distribution of the grey seal

8. The origin of the three populations of grey seals

9. Distribution of grey seals in British waters – recorded sightings

10. Distribution of grey seals in British waters – breeding areas