Since you already got an answer to the snake question (I used to have several reptiles/amphibians myself! Love them!) I'm going to address your other one...
We have a cat and a rabbit, which were both 'our babies' before I ever got pregnant (especially the cat... she was DH's constant companion). I also was feeling really maternal when I was pg with DS and cuddled the cat as often as she'd let me.
When DS was born... for a long time, it was like a switch was turned on and I just didn't have room in my heart for my cat anymore
I felt awful, but I just didn't 'love' her as much as I had (or I was just so consumed by my DS that I just didn't have as much room for the cat). She definitely missed out on a lot of attention, and started seeking attention from ANYONE who came to visit (which she had NEVER done before). We felt really bad for her, but just didn't know what to do in the first few months.
Now that DS is older (for the past year) we've been trying to make it up to our cat by spending lots of evenings with her (once DS is in bed... if he's not, she won't sit on anyone's lap for long because DS comes running over to see her). But we've noticed she's definitely back to her 'old' self. It just took us a little while to figure out where to place all the new feelings.
Although throughout the whole time, our cat has been really good with our DS. She was really interested in him when he was a baby and once he started crawling he used to take one of her cat toys and wave it around and they would 'play' together. Only now that he's reached the toddler stage (and is a little rougher) does she generally avoid him.