A formicarium is a vivarium which is designed primarily for the study of ant colonies and how ants behave. "Ant Farms," similar to these, are popular subjects for school projects. Those who study ant behavior are known as myrmecologists.
A formicarium is usually an ant colony enclosed by a transparent box made of glass or plastic. The first commercially-sold formicarium was introduced around 1929 and patented in 1931 by Frank Austin, an inventor and professor at the Thayer School of Engineering at Dartmouth College. Austin included painted or wooden scenes of palaces, farms, and other settings above the ground level, for a whimsical look.
The best-known formicariums are examples of "Uncle Milton's Ant Farm," for which the ants are sent to the purchaser through the mail, upon receipt of the coupon enclosed with the Ant Farm. The educational toy is made by Uncle Milton Industries in Westlake Village, California, and has sold over 20 million Ant Farms since 1956 and which owns the brand name "Ant Farm". This type of formicarium is for observing worker ants and its effectiveness in serious ant propagation is limited.
Formicariums and "Ant Farms" are usually made thin enough so the tunnels and cavities made by the ants can be seen and for their behavior to be studied. They can be filled with soil, loam, sand, vermiculite, other mineral fragments, or sawdust. Newer formicariums filled with semi-transparent gel (pictured right) which provides nutrition, moisture and a medium for the ants to nest, but does not supply a source of protein which is essential for the queen and larvae.
Other types of formicariums are those made with plaster, ytong (aerated concrete), or simply with no medium. Plaster nests can be made by placing modeling clay on a glass panel in the form of tunnels and chambers. The plaster is poured onto the mold and when it has dried the clay is removed and the remaining structure can be used for housing ants. The ants in this type of formicarium are very easily seen, but it can be less than comfortable for the ants. Mediumless formicariums can be in any container, with the ants staying in moist test tubes or other small containers. This also allows for better visibility, but can be less interesting because no digging takes place.
Whether ants dig or not (e.g. tree ants) a formicarium can be designed so that it is free-standing, and not enclosed or lidded like a vivarium. A free-standing design does not require high walls and a lid, but rather relies on barriers to secure the ants within their habitat; barriers include those listed below, and may include a moat of vegetable oil.
Often, containing ants inside a formicarium can be a challenge. Several substances are used to repel the ants, including vegetable oil, petroleum jelly, or PTFE(fluon). They are applied to the side of the formicarium to prevent escape. These substances are generally too slippery or sticky for the ants to walk on. Despite this, some species of ants can build bridges of debris or dirt on the substance to escape, while others demonstrate that some individuals can walk on the substance without impedance. A formicarium owner may well make use of two or more security measures.
Another way of preventing the ants from escaping is to place the entire formicarium in a shallow container of water, creating a moat.
Some formicarium owners shake their formicarium every few days so the tunnels cave in. However the first 3 days you have to let the ants get used to their new environment. This can be done by putting a black towel over the formicarium. This practice allows owners to reset the formicarium and observe their ants dig tunnels all over again. This practice, however, is done at the formicarium owner's risk, as it may compromise the safety of the ants.