from The Open University
Alternatively you can skip the navigation by pressing 'Enter'.
Studying mammals: Return to the water
Some of the most unusual and versatile of all the mammals are...
Some of the most unusual and versatile of all the mammals are the groups that live, feed and reproduce underwater. In this unit we will see how these formerly land-based mammals adapted to a return to the water, discussing such challenges as breathing, movement and communication. This is the seventh unit in the ‘Studying mammals’ series.
By the end of this unit you should be able to:
- contrast the physical properties of air and water and describe implications of such differences for aquatic mammals;
- give examples of the adaptations displayed by aquatic mammals that enable them to hold their breath while submerged for relatively long periods;
- describe some of the biological differences between pinnipeds, sirenians and cetaceans;
- discuss the importance of communication by sound in aquatic mammals, describe the role of blubber and explain countercurrent heat exchange;
- explain the diving response and its significance in natural dives;
- explain how the evolution of whales can be described within the conceptual frameworks of natural selection and punctuated equilibria.
- Duration: 10 hours
- Published on: Wednesday 8th June 2011
- Level: Introductory
- Posted under: Natural History
Studying mammals: Return to the water
Introduction

The versatility of mammals is a central theme of the ‘Studying mammals’ series of units, but surely no environment has tested that versatility as much as the rivers and oceans of the world. Mammals are essentially a terrestrial group of animals, but three major groups have independently adopted an aquatic way of life. In moving to the water, aquatic mammals have had to survive, feed and reproduce using a set of biological characteristics that evolved in association with life on land. This unit will explore how these characteristics have provided challenges, and opportunities, for mammals that spend some or all of their time in the water.
This is the seventh in a series of units about studying mammals. To get the most from these units, you will need access to a copy of The Life of Mammals (2002) by David Attenborough, BBC Books (ISBN 0563534230), and The Life of Mammals (2002) on DVD, which contains the associated series of ten BBC TV programmes. OpenLearn unit S182_8 Studying mammals: life in the trees contains samples from the DVD set. You should begin each unit by watching the relevant TV programme on the DVD and reading the corresponding chapter in The Life of Mammals. You will be asked to rewatch specific sequences from the programme as you work through the unit.
This unit is from our archive and is an adapted extract from Studying mammals (S182) which is no longer taught by The Open University. If you want to study formally with us, you may wish to explore other courses we offer in this subject area [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] .
Archive content
This is an extract from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Natural History course units or view the range of currently available OU Natural History courses.
Other pages You might like

Try: Studying mammals: Plant predators
From the mouse-deer to the elephant, plant eaters come in all shapes and sizes. But how...

Try: Studying mammals: A winning design
The term mammal encompasses a huge variety of animals, including humans. But what makes a...

Try: Animals at the extremes: Polar biology
The extreme challenges of life in the polar regions require the animals who make their...

Try: An introduction to biological...
This unit is concerned with macroevolution – the patterns and processes of evolution...

Try: Studying mammals: Life in the trees
David Attenborough looks at ‘life in the trees’: examining how species have evolved...

Try: School activities: Evolutionary tree of...
This introduction to the evolution of mammals considers Darwin’s observations on...

Try: Studying mammals: Meat eaters
The powerful and majestic carnivores are the focus of many television documentaries. In...

Try: Evolution through natural selection
In this unit, we describe the theory of evolution by natural selection as proposed by...

Try: Evolution: artificial selection and...
In the 18th and 19th century evolutionary biologists, including Darwin, emphasised the...

Try: Surviving the winter
In this unit, we study one aspect of the fluctuating nature of an organism's environment....

Try: Animals at the extremes: The desert...
Animal life has adapted to survive in the most unlikely and inhospitable habitats. This...

Try: Studying mammals: Chisellers
Ever wondered why rats, mice and squirrels seem to reproduce at such an alarming rate?...
Comments
Be the first to post a comment
Copyright & revisions
Copyright information
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements section.
Feeds
If you enjoyed this, why not follow a feed to find out when we have new things like it? Choose an RSS feed from the list below. (Don't know what to do with RSS feeds?)
Remember, you can also make your own, personal feed by combining tags from around OpenLearn.
Alternative Formats
Tags, Ratings and Social Bookmarking
Page Tags
Sign in or create a free account to add tags to your personal tag cloud using:
Taking off
Free stuff to your door
International Alphabet Soup
OU TV & Radio
-
Click: A Route 66 of the future - Ep 4BBC World Service
Wednesday 2:32 -
Click: A Route 66 of the future - Ep 4BBC World Service
Wednesday 9:32 -
Thinking Allowed: DianaBBC Radio 4
Wednesday 16:00 -
Airport Live, Episode 3BBC Two
Wednesday 20:00 -
Airport Live, Episode 4BBC Two
Thursday 20:00
Views
Votes
Comments
Tags
- climate change (374)
- business (278)
- diaries (194)
- bottom line (169)
- food (168)
- Rough Science (162)
- BBC Two (150)
- BBC Radio 4 (149)
- internet (145)
- BBC (136)
- listings (122)
- Scotland (121)
- points for debate (120)
- Bang goes the Theory (116)
- children (116)
- Creative Climate (116)
- English Civil War (115)
- Thinking Allowed (109)
- astronomy (108)
- religion (98)
- marketing (94)
- 20th century (94)
- Charles I (93)
- communication (92)
- evolution (91)
- research (89)
- sustainability (89)
- architecture (86)
- energy (83)
- Charles Darwin (78)
OpenLearn Links
Copyrighted imageCredit: Background image Lucian Milasan | Dreamstime.com 

