When an author uses a cast or part of a cast that is of a species other than Homo Sapiens, apart from the differences that are directly stated a lot of the aspects of their civilisations resemble that of humanity. There would be no real reason for these societies to have developed this way (in fact you would think that, say, wild animals would definitely avoid some of the concepts we have), but due to the existence of Acceptable Breaks from Reality this isn't noted by many audiences. This also makes creating societies of other species easier, because the audience can then use their knowledge of human lifestyles to fill in the details not given in the narrative.

Examples of this trope include: killing other beings is perceived as wrong, people buy things in shops (with money) and when people refer to a species that you have to respectful to (such as hippogrifs), that means you have to bow to them. As said, there is no reason in the real world why this sort of behaviour would exist in many cases, but fiction doesn't have to be realistic.

Many of the daily systems of other species are familiar too. The most common examples of this are things like jobs and governments. Even in Real Life animals can recognise a leader and different individuals tend towards different tasks, but the method in which this is displayed is strangely human-like in many cases. Legal processes of law courts on other planets are a sucker for this, as are aliens on the whole.

The Earth All Along trope uses this quite often - this general acceptance that other worlds are mostly like ours allows for details to be glossed over until it is revealed that the world in question is like the Earth because it is the Earth. In a similar way stories where the characters are revealed to not be humans rely on this - because as we know all civilisations operate like our own, there is no reason to assume that any work using a human-like society actually uses humans or the Earth unless explicitly stated.

This trope happens because Most Writers Are Human, and, well, you Write What You Know.

Not to be confused with Humans by Any Other Name, which has more to do with the way humans are referred to (although they aren't mutually exclusive). The Grand List of Overused Science Fiction Clichés refers to this a number of times.

Subtrope of Not So Different. Supertrope to a number of tropes (does anyone know which these are?).

Given that this trope is a Universal Trope and potentially one of the Omnipresent Tropes, notable examples and inversions only please. Otherwise we could be here for a while.

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Inversions:

• Either subverted or averted, depending on your point of view, in the classic TV series Captain Scarlet with the Mysterons who are never bodily depicted and whose societal structure is left totally unexplained.