### formation:

Burrow
* Many burrows collapse each year when mower tires pass near the burrow entrance.
* Most burrows are dug by animals
  - mammals
* Most burrows are dug by other animals
  - rodents
* Most burrows are made by animals
  - small and some large burrows are surrounded by a halo of lighter colored sediment
* Most burrows contain areas
  - chambers
  - circular chambers
  - entrances
* Most burrows contain nest areas
  - tunnel entrances
  - tunnels
  - water
* Most burrows have entrances
  - underwater entrances
* Most burrows provide homes
  - places
  - safe places
  - shelter
  - serve the dual purpose of shelter and a place to feed
* Some burrows are dug by anteaters
  - armadillos
  - badgers
  - honey badgers
  - mice
  - minks
  - nose wombats
* Some burrows are made by creatures
  - gopher tortoises
  - other creatures
  - starfishs
  - worms
  - simple tubes a few centimeters long
  - used repeatedly, sometimes for several consecutive years
  - very long with many openings
  - visited at different times by several different tortoises
* Some burrows contain numbers
  - the fossil skeleton of the beaver
* Some burrows have areas
  - doorways
  - food storage chambers
  - nest chambers
  - rest areas
  - play important roles
  - provide protection.
  * can be made in different materials. Kangaroo mice make burrows in sand. Termites make burrows in wood. Some sea urchins and clams make burrows in rock. Burrows can also be make in different shapes and sizes. Some burrows are simple tubes a few centimeters long. Others are many tunnels and rooms that connect to each other
* also provide cover
  - protection from predators
* are a favorite retreat for incubating eggs or escaping the heat of the day
  - type of trace fossil found commonly in sedimentary rocks
  - very important aspect of the ecology of desert scorpions
  - way to escape from the scathing heat of the desert
  - connected by a network of trails which often lead to rubbing posts and wallows
* are constructed beneath rocks, stumps, building foundations, or other supportive structures
  - in deep, sandy soils along dry creek beds
  - excavations made into an unconsolidated substrate
  - holes
  - lined with vegetation and are often old rodent burrows
  - most extensive in the northern part of the range where winter temperatures are coldest
* are often near water, but always above the seasonal flood line
  - the preferred home, and camouflage is commonly employed
  - shared with other rodents and lizards
  - solitary or in groups, and usually under trees
* are too, in all their functions of shelter, supply, movement, evasion, and breakout
  - of shelter,supply,movement, evasion, and breakout
  - used throughout the year, but primarily in the winter
* can be up to four feet deep, and are often found hundreds of feet from the water's edge.
* dug by badgers are also important in many areas.
* freezes with fear and forgets how to act.
* have effects
  - more than one entrance so they can take more than one route in or out
  - strong effects
* is the single parent of two children.
* located in flat grassy areas have several entrances.
* loosen the soil, admitting air and water, and helping roots grow.
* often open at edge or rock, near base of tree, or under the edge of a building.
* provide entries
  - excellent shelter from predators and the weather extremes
  - habitat for numerous other species, including reptiles, amphibians and insects
  - protection against predators and extreme weather conditions
  - rats with shelter and food storage, as well as safe, thermo-regulated nest sites
  - woodchucks with elaborate protection
* reach five feet below ground and length-wise extend for thirty feet.
* show zonation with young crabs found closer to shore, near water.
* sometimes penetrate or weaken the river banks.
* tend to be highly uniform in their distribution, while mounds tend to be highly patchy.