[2] Sulfolobus species grow in volcanic springs with optimal growth occurring at pH 2–3 and temperatures of 75–80 °C, making them acidophiles and thermophiles respectively.

Other species can be found throughout the world in areas of volcanic or geothermal activity, such as geological formations called mud pots, which are also known as solfatare (plural of solfatara).

When the first Archaeal genome, Methanococcus jannaschii, had been sequenced completely in 1996, it was found that the genes in the genome of Methanococcus jannaschii involved in DNA replication, transcription, and translation were more related to their counterparts in eukaryotes than to those in other prokaryotes.

They also code for citrate synthase and two subunits of 2-oxoacid:ferredoxin oxidoreductase, which plays the same role as alpha-ketoglutarate dehydrogenase in the TCA (tricarboxylic/Krebs/citric acid) cycle.

Other genes in the respiratory chain which partake in the production of ATP were not similar to what is found in eukaryotes.

S. solfataricus has been found in different areas including Yellowstone National Park, Mount St. Helens, Iceland, Italy, and Russia to name a few.

Another species, S. tokodaii, has been located in an acidic spa in Beppu Hot Springs, Kyushu, Japan.

Sediments from ~90m below the seafloor on the Peruvian continental margin are dominated by intact archaeal tetraethers, and a significant fraction of the community is sedimentary archaea taxonomically linked to the crenarchaeal Sulfolobales (Sturt, et al., 2004).

[15] Ajon et al.[14] showed that UV-induced cellular aggregation mediates chromosomal marker exchange with high frequency in S. acidocaldarius.

Wood et al.[16] also showed that UV-irradiation increased the frequency of recombination due to genetic exchange in S. acidocaldarius.

The pili encoded by this operon are employed in promoting cellular aggregation, which is necessary for subsequent DNA exchange between cells, resulting in homologous recombination.

They are also unique in the sense that the genes encoding the structural proteins of the virus are constantly transcribed and DNA replication appears to be induced.

The viruses infecting archaea like Sulfolobus have to use a strategy to escape prolonged direct exposure to the type of environment their host lives in, which may explain some of their unique properties.