**`why do the gods resemble human beings rather than other animals?`**  

I am providing  answer of your question from  [**Aitareya Upanishad** ][1] vreses.

It's said in the Upanishad that In the beginning  the absolute Self was alone.  Then  He thought, "Let Me create the world's". & then  He created the world's.

> स ईक्षतेमे नु लोका लोकपालान्नु सृजा इति सोSद्भ्य एव पुरुष
> समुद्धृत्यामुर्छयत् ||1.1.3||
> 
> Sa IkshaTeme Nu Loka LokaPaLaaNuu Sruja Iti<br> SoDbhya Eva Purusha
> SaMuDdhruTyaMurchhayat 
> 
> He thought, "These then are the worlds. Let Me create the protectors
> of the worlds." **Having gathered up a (lump of the) human form** from the
> water itself, He gave shape to it.

So It’s said that the creator took lump (like clay) and given the shape to it like Purusha  i.e a humanoid form Or figure - with head , hands  etc. That we call as Virat purusha .
<hr>
Then he created the deities. And He subjected Him (i.e. Virat Purusha ) to hunger and thirst. Then the deities asked lord to provide the abode for them ,from where they can eat food. Then..

> ताभ्यो गामानयत्ता अब्रुवन्न वै नोSयमलमिति | <br> ताभ्योSश्वमानयत्ता
> अब्रुवन्न वै नोSयमलमिति ||1.2.2||
> 
> Tabhyo GaaMaaNaYaTta  AbruVaNna Vai NoYamLMiti  <br>  Tabhyo
> ShawaMaaNaYaTta AbruVaNna Vai NoYamLMiti <br>
> 
> For them He (i.e. God) brought a **cow**. They said, "This one is not
> certainly adequate for us." For them He brought a **horse**. They said,
> "This one is not certainly adequate for us."

It’s said here that the lord bought the lump (Pinda) ,creature   shaped like cow and horse. But   the deities said that these shapes are not good for us to have our food in right way Or adequately .
<hr>
Then he bought the Virat Purusha in human form to  them and they liked it.

> ताभ्य: पुरुषमानयत्ता अब्रुवन् सुकृतं बतेति | <br> पुरुषो वाव सुकृतम् |
> ता अब्रवीद्यथायतनं प्रविशतेति ||3||<br>
> 
>  For them He brought a man. They said **"This one is well formed; man
> indeed is a creation of God Himself".** To them He said, "Enter into
> your respective abodes".

<hr>

Now although deities entered into their respective abodes i.e  Indriyas ,but we can’t represent them like organs. Like we can’t graphically represent Prana   Vayu as Or Mind as Chandrama. And even its not appropriate to represent deities like organs also cause then they will not look like divine beings.

> **Conclusion** - So I think as deities liked this humanoid form because it is indeed the most beautiful creation of lord  and found it
> appropriate to reside for receiving food I.e prayers etc. **That
> indirectly means they specifically chosen this form in which they
> should have to be worshiped ,** We generally depict them in human
> form.And that is the reason why gods looks like human beings.

  
[1]: http://www.celextel.org/upanishads/rig_veda/aitareya.html