I have had both G. piggies and hamsters

1- hamsters have sharp neddle like teeth and can bite, chew threw things too also the males a eat the babies if they are in same cage as momma when she gives birth. But if they are handled when they are young they get used to it and do well with being held or you could just use gloves to be safe.

2 G piggies are more social loved to be held and have attention poured upon them but also kinda messy and need clean cage .

Hamsters you could keep in a small cage and get one of those exercise ball things and let it roll around a room. or those tubes that connect and make a tunnel play ground.

G piggies cant use a ball like that because of their body shape ( their back arent made for that kind of thing.) and they do better in a larger cage like for a rabbit.

I prefered my G piggies ...only keeping the cage clean was more work then the hampsters cage (actuly we kept hampster in a small fish tank we had already)
I found no diffrence in the sex just dont get one girl and one boy lol.

Good luck and give Grand monkey a birhtday hug from me.
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.tell him yes I have swam with a dolphine before but only once.
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