Opossums are also nocturnal, they’ll awaken after sundown and usually find a place to sleep before daylight, not ideal hours for a pet.  They sleep 18 to 20 hours a day.   
​

They’re omnivores (they’ll eat nearly anything) and yet have extraordinarily special dietary needs which change as the opossum ages.  Trying to balance their calcium needs with vitamin d3, the right amount of veggies, fruits, protein, fat, the right amount of snails, slugs, and bugs along with everything else requires scientific precision. The risk of them developing metabolic bone disease from an imbalanced diet is too great.
 

Opossums need a large territory; they have a range of up to ½ mile nightly.  They don’t like to sleep in the same place for more than a few days.  Keeping one in a cage is cruel and causes them physical and emotional harm.   ​
 

Then there’s the poop.  They don’t like to poop in the same place too often so forget about housebreaking one.   
​

Knowing all this, still thinking about it?  Remember their lifespan is very short; in the wild 18 to 24 months and in captivity if you do everything near perfect possibly three years.  You just get to know them and they’re gone.   
​

Lastly a very big problem; they are illegal to keep.  No New England state allows opossums to be kept captive, there are very strict laws against it.   ​