Galaxies do not "steal" dark matter from each other in the traditional sense. Dark matter is a mysterious form of matter that does not interact with light or other electromagnetic radiation, making it difficult to observe directly. Its presence is inferred through its gravitational effects on visible matter.
When galaxies interact or merge, their gravitational forces can influence the distribution of dark matter. During such interactions, the dark matter halos of the galaxies can merge and redistribute, resulting in a new configuration of dark matter. This process can lead to the growth of dark matter halos and the formation of larger structures.
It's important to note that the term "steal" might imply an intentional action, but galaxies and dark matter do not possess consciousness or deliberate behavior. The gravitational interactions between galaxies are governed by the laws of physics and occur naturally over vast timescales.
Observations and simulations suggest that galaxy mergers and interactions can influence the distribution of dark matter, but the precise details are still an active area of research. Scientists use computer simulations and observational data to study the dynamics of galaxies and their dark matter halos, helping to deepen our understanding of how galaxies evolve and how dark matter contributes to their structure.