This article is not a good source.

1. Possums are not native to China or new Zealand. Australia is correct but they can also be native to New Guinea and parts of Indonesia.
2. Certain species of possums like the ringtail can have partially hairless tails.
3. When comparing to Australia’s most common possum (Brushtail, max 4.5kg), the Virginia opossum is bulkier but has roughly the same body length. The largest possum (Bear Cuscus is nearly twice as big)
4. Sources vary but it’s clear there are significantly more opossum species than possum species.Possums species are much more distinct though.

One has a Japanese honorific prefix and the other does not.

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Not happy with all the anti-possum ads on that page. Opossums are beneficial good creatures, just leave em be.

One is Irish.

Herr’s a handy video to explain the difference. Too bad I can never remember anything said.

The main difference is that people commonly refer to opossums as possums, but rarely the other way 'round.