The Open University since 2006
Alternatively you can skip the navigation by pressing 'Enter'.
More or Less: How many cows for a fiver?Sunday, 4th December 2016 20:00 - BBC Radio 4 BBC Radio 4
The Secret History of Our Streets - London: Arnold CircusTuesday, 6th December 2016 22:00 - BBC Four
The Secret History of Our Streets - London: Arnold CircusThursday, 8th December 2016 00:45 - BBC Four
Vienna: Empire, Dynasty and Dream: Episode 1: The Imperial City 1160-1683Thursday, 8th December 2016 21:00 - BBC Four
More or Less: How many cows for a fiver?Available for over a year
Colour: The Spectrum of Science: Episode 1: Colours of EarthAvailable until Saturday, 31st December 2016 23:00
BBC Inside Science - 2016/2017 series: Alzheimer's research, Lucy, Glowing bandage package, Supernovas to HollywoodAvailable for over a year
The Secret History of Our Streets - London: Reverdy RoadAvailable until Saturday, 31st December 2016 01:30
Human Rights Week10 December is Human Rights Day but here at The Open University we'll be exploring progress made... Read more: Human Rights Week
Take the photographic memory testCan you capture scenes just by looking at them? Find out with our photographic memory test. Launch now: Take the photographic memory test
Exploring equality and equity in educationThis free course, Exploring equality and equity in education, considers the complexity of social... Try: Exploring equality and equity in education now
Organisations and management accountingThis free course, Organisations and management accounting, examines the nature of organisations,... Try: Organisations and management accounting now
From the mouse-deer to the elephant, plant eaters come in all shapes and sizes. But how do they manage to flourish on a salad diet? In this free course, Studying mammals: Plant predators, we will examine the special features that allow them to extract their nutrients from leaves, and see how some plants protect themselves from these predators. This is the fourth course in the Studying mammals series.
After studying this course, you should be able to:
- describe the particular problems in digesting plant material
- give examples of the ways in which teeth are modified for a herbivorous diet
- explain the importance of digestive enzymes
- explain the importance of microbes in digesting plant material
- compare the main features of the digestive systems of ruminants and hindgut fermenters.
- Learning outcomes
- 1 The herbivores
- 2 The herbivore lifestyle - living on leaves
- 3 Herbivore teeth
- 4 Digesting plant material
- 5 Digestive processes
- 6 Grazers and browsers
- 7 Plant defences
- 8 Shortage of nutrients
- 9 Wildebeest migration
- 10 Living in herds
- Keep on learning
Study this free course
Enrol to access the full course, get recognition for the skills you learn, track your progress and on completion gain a statement of participation to demonstrate your learning to others. Make your learning visible!
Animals in the third suborder of the Artiodactlya, the pigs, peccaries and (according to most authorities) the hippopotamuses (suborder Suina), use a slight variant on the ruminant method, and are often referred to as pseudo-ruminants. You might like to add this information to your version of Table 2. These animals do have stomachs with several chambers, similar to the true ruminants, and the first of these chambers houses colonies of cellulose-digesting microbes. However, the pseudo-ruminants do not gain maximum benefit from this arrangement because they do not regurgitate the food and 'chew the cud'. So they are not able to extract as much of the nutrition from a diet of leafy plant material as a similarly-sized ruminant.
Pigs and peccaries overcome the problem by eating a varied diet, not exclusively composed of leafy plant material. As well as leaves and grasses, they eat fungi, ferns, roots, bulbs and corms, and fruit (all of which are easier to digest) and even some animals such as insect larvae, earthworms and sometimes small vertebrates like frogs and mice, which they come across while rooting in leaf litter and moist earth. The hippopotamus has evolved a different strategy to counterbalance its less efficient digestion - it reduces its energy expenditure.
Reread LoM pp. 99-102 and note down the aspects of the lifestyle of the hippopotamus that reduce its energy expenditure.
Hippos spend their days wallowing in tepid, shallow water, so they do not need to expend energy in keeping warm. In fact, their cellulose-digesting microbes produce so much heat that these mammals risk overheating. The water supports the weight of their bodies and they generally move around very little in the water (though the one pictured on p. 100 is obviously on the move). So, during the day they expend little energy. Their main energy requirement is at night, when they climb out of the water to feed on grass on the riverbanks, travelling perhaps a few kilometres each night.
So hippos have a relatively inefficient digestive system, compared with true ruminants, but also have a low energy requirement. The herbivorous mammals that have taken the low-energy lifestyle to its extreme are, of course, the sloths. You might like to reread LoM pp. 87-90 to remind yourself about these animals (and perhaps watch them again in the first few minutes of the TV programme).
This free course includes adapted extracts 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 courses or view the range of currently available OU Natural History courses.
Copyright & revisions
Originally published: Wednesday, 16th March 2016
Last updated on: Wednesday, 16th March 2016
- 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 and our FAQs section.
- This site has Copy Reuse Tracking enabled - see our FAQs for more information.
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.
All our alternative formats are free for you to download, for more information about the different formats we offer please see our FAQs. The most frequently used are Word (for accessibility), PDF (for print) and ePub and Kindle to download to eReaders*.
- Word (1.3 MB)
- PDF (2.7 MB)
- ePub 3.0 (1.1 MB)
- ePub 2.0 (1.1 MB)
- Kindle (447 KB)
- RSS (198 KB)
- HTML (948 KB)
- SCORM (946 KB)
- OUXML Package (27 KB)
- OUXML File (80 KB)
- IMS Common cartridge
- Moodle backup (490 KB)
*Please note you will need an ePub and Mobi reader for these formats.