Which type of wood?

[LORI34205]

I am looking around and getting ready to buid a cage for my sav because he is growing very quickly!
i am going to make a cage 8x4x3 which i think is big enough?
i want some opinions on what wood to use, i think i will use 4x8 sheets of sandiply hardwood plywood three fourths of an inch thick,it is very smooth,i will stain it and coat it with a layer of(i forget what it is called,its like a sealent stuff.)Does that sound good or do some other people have other suggestions?