Are 'dangerous' and 'aesthetically ugly' one and the same thing?

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Are 'dangerous' and 'aesthetically ugly' one and the same thing? I read somewhere once, that arachnophobia evolved as a defence mechanism against dangerous spiders. Even though most spider species are harmless, this evolved response is still there, as it is better to avoid all spiders, even the harmless ones to avoid being bitten by the really deadly ones. Seeing as this aesthetic disgust and fear arose for the purpose of keeping one safe, and very few spiders are actually dangerous, would it be incorrect to view the harmless ones as ugly? Similarly, there are some dangerous animals I consider quite beautiful: tigers, for example. Would it be incorrect to view them as beautiful because they are dangerous? Basically, what I'm trying to ask is, because perception of ugliness evolved to keep us from danger, is danger synonymous with ugliness and is any visual beauty we ascribe to a dangerous animal simply an illusion? Conversely, are non-dangerous animals that we find ugly actually visually beautiful even if we do not perceive them as such?