Chapter 31, Problem 13STP

Summary Introduction

To compare:

The organisms in the order Rodentia with those in order Lagomorpha.

Introduction:

Rodents are mammals that are identified by a single pair of the incisors growing in both the upper and lower jaws. They are found in huge varieties in different parts of the world.

Lagomorphs are the terrestrial herbivores that quite resemble rodents as both have the growing incisor teeth in them. They differ only in dentition and jaw structure.

Explanation of Solution

Lagomorphs differ from rodents as the former have four incisors in the upper jaw and the latter does not.

Rodents

1. Rodents like beaver, rats, marmots, squirrels and hamsters form 40 percent of all mammalian species.
2. They got two-pairs of razor-sharp incisor teeth that continue to grow throughout life.
3. They use their sharp teeth to move through wood, seed pods or shells while looking for food.
4. Their ability to invade all land habitats and their successful reproductive behavior have made them ecologically important in all terrestrial ecosystems.

Lagomorphs

1. Lagomorphs like rabbits, pikas and hares have long sharp incisors that keep growing.
2. They also have a pair of peg-like incisors that grow behind the first pair.
3. These are herbivores.
4. Pikas live in high altitudes where the ground is covered with snow. These grass-eaters adapt the conditions by harvesting grass during the warm months and store it that they use later when no vegetation is available.

Conclusion

Lagomorphs are similar to mammals that have hair, four limbs and mammary glands and are endotherms. Rodents are little animals that contain robust bodies, small limbs and very long tails. They got sharp incisors that help them in making burrows and defending themselves.