Burrow

A burrow is a hole or tunnel excavated into the ground by an

A large variety of vertebrates construct or use burrows in many types of substrate; burrows can range widely in complexity. Some examples of vertebrate burrowing animals include a number of

Invertebrate burrows

Scabies mites construct their burrows in the skin of the infested animal or human. Termites and some wasps construct burrows in the soil and wood. Ants construct burrows in the soil. Some sea urchins and clams can burrow into rock.

The burrows produced by invertebrate animals can be filled actively or passively. Dwelling burrows which remain open during the occupation by an organism are filled passively, by gravity rather than by the organism. Actively filled burrows, on the other hand, are filled with material by the burrowing organism itself.^[15]

The establishment of an invertebrate burrow often involves the soaking of surrounding sediment in mucus to prevent collapse and to seal off water flow.^[15]

Examples of burrowing

Burrowing animals can be divided into three categories: primary excavators, secondary modifiers and simple occupants.[16] Primary excavators are the animals that originally dig and construct the burrow, and are generally very strong.^[17] Some animals considered to be primary excavators are the prairie dog, aardvark and wombat.^[18] Pygmy gerbils are an example of secondary modifiers, as they do not build an original burrow, but will live inside a burrow made by other animals and improve or change some aspects of the burrow for their own purpose.^[17] The third category, simple occupants, neither build nor modify the burrow but simply live inside or use it for their own purpose.^[17] Some species of bird make use of burrows built by tortoises, which is an example of simple occupancy.^[17] These animals can also be referred to as commensals.^[17]

Protection

Some species may spend the majority of their days inside a burrow, indicating it must have good conditions and provide some benefit to the animal.^[19] Burrows may be used by certain species as protection from harsh conditions,^[20] or from predators.^[13] Burrows may be found facing the direction of sunlight or away from the direction of cold wind.^[21] This could help with heat retention and insulation, providing protection from temperatures and conditions outside.^[21] Insects such as the earwig may construct burrows to live in during winter, and use them for physical protection.^[20] Some species will also use burrows to store and protect food. This provides a benefit to the animal as it can keep food away from other competition.^[19] It also allows the animal to keep a good stock of food inside the burrow to avoid extreme weather conditions or seasons where certain food sources may be unavailable.^[19] Additionally, burrows can protect to animals that have just had their young, providing good conditions and safety for vulnerable newborn animals.^[19] Burrows may also provide shelter to animals residing in areas frequently destroyed by fire, as animals deep underground in a burrow may be kept dry, safe and at a stable temperature.^[21]

Fossil burrows

Burrows are also commonly preserved in the

Wikimedia Commons has media related to Burrows.

• Holt
• Maternity den
• Sett - a network of badger tunnels.
• Spreite
• Subterranean fauna
• Communal burrow

References