Of course, small animals have shorter tracts than big animals. So to make comparisons, scientists measure the length of the digestive tract relative to the animal's body length. For example:vultures – body length 75 cm, digestive tract 220 cm, so on average, vulture digestive tracts are 2.9 times the length of their bodieskoalas – body length 80 cm, digestive tract 570 cm, so on average, koala digestive tracts are 7.1 times the length of their bodieshumans – body length 167 cm, digestive tract 900 cm, so on average, human digestive tracts are 5.4 times the length of their bodiesQuestion 9 Key QuestionCompare the ratios of digestive tract to body length in vultures and koalas. How can the differences be explained by their different diets?

The ratio of digestive tract length to body length in vultures is 2.9, while in koalas it is 7.1. This means that the digestive tract of a koala is relatively longer than that of a vulture.

The difference in these ratios can be explained by the different diets of these two animals. Vultures are carnivores, meaning they primarily eat meat. Meat is relatively easy to digest, so a shorter digestive tract is sufficient.

On the other hand, koalas are herbivores that primarily eat eucalyptus leaves, which are tough and fibrous. The digestion of plant material requires more time and a longer tract to allow for the breakdown of tough fibers and extraction of nutrients. Therefore, koalas need a longer digestive tract relative to their body length.

In addition, the longer digestive tract in koalas also allows for a larger population of gut bacteria to break down the tough eucalyptus leaves, which is another reason why herbivores often have longer digestive tracts than carnivores.