Cow dung
Cow dung, also known as cow pats, cow pies or cow manure, is the waste product of bovine animal species. Cow dung is the undigested residue of plant matter which has passed through the animal's gut. The resultant faecal matter is rich in minerals. Color ranges from greenish to blackish, often darkening soon after exposure to air.

Uses
Cow dung, which is usually a dark brown color (usually combined with soiled bedding and urine), is often used as manure (agricultural fertilizer). If not recycled into the soil by species such as earthworms and dung beetles, cow dung can dry out and remain on the pasture, creating an area of grazing land which is unpalatable to livestock.
In many parts of the developing world, and in the past in mountain regions of Europe, caked and dried cow dung is used as fuel.

Dung may also be collected and used to produce biogas to generate electricity and heat. The gas is rich in methane and is used in rural areas of India and Pakistan and elsewhere to provide a renewable and stable source of electricity.
In central Africa, Maasai villages have burned cow dung inside to repel mosquitos. In cold places, cow dung is used to line the walls of rustic houses as a cheap thermal insulator. Most of villagers in India spray fresh cow dung mixed with water in front of the houses to repel insects. It is also dried into cake like shapes and used as replacement for firewood.
Cow dung is also an optional ingredient in the manufacture of adobe mud brick housing depending on the availability of materials at hand.

Ecology
Cow dung provides food for a wide range of animal and fungus species, which break it down and recycle it into the food chain and into the soil.
In areas where cattle (or other mammals with similar dung) are not native, there are often also no native species which can break down their dung, and this can lead to infestations of pests such as flies and parasitic worms. In Australia, dung beetles from elsewhere have been introduced to help recycle the cattle dung back into the soil.
Cattle have a natural aversion to feeding around their own dung. This can lead to the formation of taller ungrazed patches of heavily fertilized sward. These habitat patches, termed "islets", can be beneficial for many grassland arthropods, including spiders (Araneae) and bugs (Hemiptera). They have an important function in maintaining biodiversity in heavily utilized pastures.