Something that helps me a lot when developing and making art of the various Mass Effect species, is keeping in mind what real-life animals they could be based off of. Here, I have compiled a list of the main animals I believe each species takes inspiration from. This way, one can get a clearer image of how that alien may function both biologically and socially. Bear in mind that many of these are based off of my own perception!
Asari = Orcas
Salarians = Frogs
Krogan = Tortoises
Turians = Parrots (Specifically Cockatoos)
Quarians = Felines (headcanon)
Batarians = Bats (Specifically Vesper Bats)
Volus = Walrus (headcanon)
Elcor = Elephants
Hanar = Jellyfish
Drell = Lizards (Specifically Anole)
Angara = Seals














