3 Is specialisation always advantageous?
Specialisation generally implies the possession of adaptations that make animals particularly effective or efficient in one or more aspects of their lives. In many of the examples used in other units in this series, mammals are likely to possess adaptations related to the acquisition and/or processing of food.
Question: What is the most accessible and frequently used indicator of a mammal's diet in both living and fossil species?
A mammal's dentition often gives a very good indication of the sort of food to which it is adapted.
Insect eaters (course S182_2) usually have relatively small, sharp teeth (for example, tenrecs [p. 51]) or lack them altogether (as do anteaters). Some grazers have blade-like incisors with which they cut clumps of vegetation (course S182_4) and most have large molars which they use to grind the food before swallowing it. Many of the carnivores in course S182_5 have a veritable armoury of stabbing canines, slicing carnassials and bone-crushing molars.
Question: What is the main advantage to a group of mammals of developing adaptations - in particular, dentition - that enable it to specialise in the food it eats?
Possession of appropriate adaptations, enabling a group of mammals to specialise in a particular sort of food, probably makes it more efficient at exploiting that food resource than any of its potential competitors.
However, there is inevitably a 'down side' to specialisation. If, for any reason, a food resource becomes less available than formerly, a highly specialised mammal would probably be unable to compete effectively for alternative food resources, because other mammals would already be more efficient at exploiting these resources.
You'll be aware that several groups of mammals have adopted an entirely different strategy when it comes to food. In effect, they have specialised in being non-specialists. These mammals have acquired and retained the ability to turn to a wide range of different food resources according to availability. It is to the biology of these opportunistic feeders - the omnivores - that we turn our attention in the remainder of this course.