Physically, they resemble dark green humanoid heads with several branched tendrils; and need a sophisticated robotic suit containing their own atmosphere in order to survive on other planets. It has been stated that the helium regenerator is a vital constituent of the Arcturan armor, suggesting that they may require large quantities of it to live; which is most surprising since helium is a noble gas.
It is also known that the Arcturan homeworld is poor on mineral resources. First contact between Humans and Arcturans apparently occurred in 2085, when both species signed the Arcturan Treaty. This has been described as the first official instrument of peaceful interaction between humans and aliens.
In the 39th century, Arcturans were members of a Galactic Federation, together with such other species as Humans, Ice Warriors and Alpha Centaurans. However the Arcturan ambassador to planet Peladon attempted to prevent that planet's joining the Federation in order to exploit its mineral resources for Arcturus.