Why did Darwin keep his idea to himself for so long?

Darwin kept his theory of evolution by natural selection largely to himself for many years due to several factors, including the fear of backlash from the scientific community and religious institutions, which held significant power at the time. He was also concerned about the potential societal implications of his ideas, fearing they could challenge established beliefs and norms. Additionally, Darwin wanted to gather extensive evidence to support his theory before presenting it, which contributed to the delay in his publication. Ultimately, he published "On the Origin of Species" in 1859 after being prompted by the work of Alfred Russel Wallace, who independently arrived at similar conclusions.