# Rodents
## Overview
Rodents form a large family of small and medium sized mammals found on many inhabited planets. Most species have strong front teeth that continue to grow throughout their lives. They use them to cut food, open hard fruit and shape their nests.
They are highly adaptable and can survive in forests, cultivated plains, steppes, deserts and underground facilities. Many species live near human settlements, where they find food in storage areas, fields and waste disposal sites.
## Underground Nests
Many rodents build underground nests with complex networks of tunnels. Their nests may include food storage areas, chambers where their young are born and several escape routes.
The animals remove soil with their front feet and widen narrow passages with their teeth. Some species can dig even through hard, rocky ground. When a tunnel collapses, they sense changes in the air and vibrations in the ground and quickly begin opening a new passage.
Abandoned nests are often used by smaller animals. Over time, the constant digging of tunnels aerates the soil and carries seeds deeper underground.
## Diet and Behavior
Most rodents feed on seeds, fruit, roots and small plants. Some species eat insects, eggs or the remains of dead animals when plant based food is scarce.
They collect more food than they immediately need and carry it into their underground storage chambers. Some of the seeds remain there and may eventually grow. For this reason, despite the damage they cause to crops, rodents contribute to the spread of many plants.
They form family groups and communicate through scents, body movements and sounds. Some of these sounds are outside the range of human hearing.
## Known Species
- **murin**: A small rodent with short grey or brown fur, a long tail and strong front feet. It lives in colonies and digs narrow underground tunnels through which a human can move only with difficulty. It can sense vibrations in the ground and reacts immediately to collapses. It is commonly found on arid planets and near mines.
- **talek**: A rodent slightly larger than a murin, with a round body, small ears and thick fur. It stores large quantities of seeds inside its nest and can remain underground for long periods. Farmers consider it a pest because it enters grain storage areas.
- **ravan**: A medium sized rodent, approximately the size of a small Gallis. It has a long body, powerful jaws and hard claws. It lives alone or in small family groups and digs deep nests in hills and rocky steppes. It can become aggressive when threatened.
- **korven**: The largest of the commonly known rodents, with a body approaching the size of a large Gallis. It has a short tail, a broad head and thick fur that protects it from the cold. It builds spacious underground nests and often moves enough soil to alter the shape of a small area.
## Relationship with Humans
Rodents have followed human settlements since the earliest periods of recorded history. They find food among crops and shelter inside human structures. They can easily enter storage areas, spacecraft and underground accommodation through openings that larger animals cannot use.
Humans usually regard them as pests. They destroy stored food, injure small domesticated animals and damage cables or insulating materials. On some worlds, however, they are bred for their meat or fur, or kept as companion animals.
Their presence can also provide warning of environmental changes. Rodents suddenly abandoning their nests are often considered a sign of underground collapse, flooding or seismic activity.
## Evolution
Zoologists have identified genetic and anatomical similarities between rodents and many larger mammals. According to the prevailing theory, a large number of modern mammals descended from small ancestors that resembled present day rodents.
Their small size, rapid reproduction and ability to live underground allowed these early ancestors to survive major environmental disasters. After larger animals became extinct, their descendants spread and evolved into many different species.
The theory does not explain why related rodents appear on planets that had no known contact with one another before they were connected to the beacon network. This question is usually examined within the context of the Common Origin Theory.

Category: Society Tags: Animals