Aniline is a leather treatment, not a leather type. Aniline leather can be kangaroo, sheep,or indeed any animal.
Most top end gloves are made using Aniline leather. The Aniline treatment is the process of dying the leather to the desired colour whilst retaining visibility of the natural grain structure, pores etc of the animals skin. If you look closely you will see what I mean, despite the colouring of the leather, the surface will resemble the animals skin surface.
Cheaper gloves will be semi aniline, where an obvious coating is visible over the top of the leather, usually this is somewhat transparent. Very cheap gloves may be PVC or if they are leather, are likely to be totally coated, with no naturally occurring blemishes, grains, pores etc from the skin being visible.