Even if you've never seen one of these creatures in real life, you've probably seen pictures! Opossums are marsupials (not rodents!) who can be seen all over North America. They're known as scavengers, i.e. animals that eat the leftovers that other animals eat, including humans. Most humans encounter opossums digging through their rubbish, or hissing at them and digging holes in the garden, so think they're just grubby little pests. But that's actually a lot more to these furry little critters - do you know what disease they help prevent, or what they can do with their tails? Read on for more info! Don't forget to check out some more animal facts - learn all about cheetahs, honey badgers, or even capybaras!

1. They're completely different from possums

In North America, the words "possum" and "opossum" mean the same thing, but in Australia a possum is a totally different animal. Australian possums are very cute looking critters that kind of look like squirrels - American opossums are also cute but in a more toothy, scrappy kind of way! The word "possum" is often used in the States to refer to the opossum, though, which can get a bit confusing.

2. They're the only North American marsupials

A marsupial is a kind of animal that carries its babies in pouches on their bodies. There are lots in Australia (kangaroos, wombats, wallabies, koalas) but the opossum is the only one you'll find in the USA!

3. There's more to their famous trick than you might think

Opossums are most famous for "playing possum", which means pretending to be dead in front of predators so the predator will leave it alone. This is actually a fear response from the opossum and not a great piece of acting - due to stress the opossum seizes up and flops over with its tongue sticking out. It can stay that way for hours, and the opossum has no control over when it starts and when it stops.

4. ..and playing possum gets grosser

Ever the method actor, the opossum really sells the performance of being dead by secreting a stinky odour from its bum. The predator thinks that the opossum is too rotten to eat and will go and look for dinner elsewhere. Yum!

5. They're little furry buses

Mother opossums are often seen with their babies (who are called "joeys", just like kangaroos) sitting on their backs. The joeys will stay with their mother until they're about four months old, and they'll climb on her back the whole time! Their little feet are very good at clinging to their mum's fur, and they'll scramble all over her like a jungle gym!

6. They help prevent disease

Opossums are famous for eating from rubbish bins, so people think that they're dirty and spread diseases - when in fact the opposite is true! Lots of mammals carry ticks which can spread Lyme disease, a nasty bacterial infection (and the reason why you should look out for ticks in grassy and wooded areas). Opossums however tend to gobble up the ticks that attach to them, stopping them from spreading the disease further.

7. They almost never get rabies

Rabies is a very nasty infection, this one spread by animal bites, especially from dogs - in the UK it's most common in a small number of wild bats, which is why you shouldn't try to handle an injured bat if you find one (call the RSPCA instead)! Marsupials aren't totally immune to the illness but it's actually very rare for them to have it, because their body temperature is too low to provide a good environment for rabies to flourish.

8. They groom themselves, a LOT

So, they help stop Lyme disease and they don't spread rabies - but they still eat trash and smell terrible right? Not quite! Trash-eating aside opossums are actually very dedicated at grooming themselves. They use their tongues and paws to keep themselves clean, just like cats. They don't have many sweat glands, which means that most of the time (when they're not playing possum) they don't really smell of anything. This is useful for avoiding predators!

9. There are some weird urban legends about them

Like any animal that spends a lot of time around people, some strange myths and legends have popped up around the opossum. One very weird one is that they give birth through their noses. They don't, of course - no animal does, or at least none that we know of! But it's thought that this legend came about because mother opossums tend to groom their stomach and pouch before they give birth, often making sneezing sounds as they do so. Long ago someone probably noticed this, then noticed the newborn babies in the mother's pouch, and reached the (totally wrong) conclusion!

10. They have very good memories

Opossums are actually very good at remembering stuff - especially if it involves food! One study found they were better than rats, dogs, pigs and cats when it came to remembering which route led them to a tasty treat. They can also recall the smell of harmful substances and know to avoid eating them.

11. They have five limbs

Opossums are sometimes mistaken for rodents because of their long, ratlike tails. These tails are "prehensile" - this means they can move their tails like an extra arm or leg. They use their tails to carry extra material for their nests, and for extra stability when climbing trees. They can even hang from branches by their tails for a short amount of time!

12. They're immune to most snake venom

In addition to their amazing anti-rabies ability, opossums are actually immune to most types of snake venom. This means that they can eat snakes, and not just play dead in front of them! The only snake known to be an exception to this is the coral snake, a very venomous snake mostly found in the southeastern USA. Scientists want to replicate this ability in humans, but haven't quite figured out how.

13. They're social animals

Despite looking kind of mean, opossums have actually shown some social tendencies They will share dens in captivity, with 13 grown-up opossums sharing the same den in one study. Scientists think they might do this in the wild, too.

14. They're not great in cold weather

Even though they have warm furry coats, their ears and prehensile tails are hairless. This means that opossums don't do so well in the cold - they can't put on hats and warm socks! It's quite common for opossums in colder states to have noticeable frost damage to their ears and tails. Opossums are nocturnal, so they mostly hunt for food at night time, but in winter they have been observed foraging during daylight hours when it's less cold!

15. They're living fossils, sort of

When an animal is a "living fossil" it means that it hasn't changed much for several million years. While opossums might not be as old as scientists first thought (around 70 million years), they are probably at least 20 million years old, which is still saying a lot!