Some of the smallest of all galaxy types, dwarf irregular galaxies (dIrr) are very loose and small galaxies containing as few as a couple thousand stars, putting them very close to globular clusters. They are known to have low metallicity, meaning they are good indicators as to what the universe was like when it formed. While somewhat common as satellites around larger spiral or elliptical galaxies, they are difficult to separate in classification from normal irregular galaxies. A few dwarf irregular galaxies in our universe include UGC 4459 and the Canis Major Dwarf.