It's estimated that some 334,000 U.S. households have ferrets, according to the American Veterinary Medicine Association.

That's far lower than the number of cats and dogs, of course, but many people happily share their homes with them.

While these domesticated weasels have a reputation for being adorable — if a little stinky — there's a lot more to ferrets than you may realize.

1. Newborn Ferrets Are so Small They Can Fit Inside a Teaspoon

baby ferrets These baby ferrets were about a week old when the photo was taken. (Photo: USFWS Mountain-Prairie/Flickr)

The average ferret will grow to about 20 inches long and weigh 1.5 to 4 pounds, but when they're born, the animals are tiny, weighing about an ounce.

2. They Have Poor Vision

Because they're extremely nearsighted, ferrets rely on their excellent hearing and sense of smell to navigate the world. It's not uncommon for pet owners to witness their furry little friends running into walls or furniture.

"Ferrets are generally uncoordinated and clumsy, and their vision is poor," veterinarian Mark Burgess told Small Animal Channel. "Most can only see a couple feet in front of them, and they have very bad depth perception, which explains a lot of their klutziness."

3. They're Hard Workers

Felicia the ferret Felicia the ferret earns her keep by cleaning out some vacuum piping. (Photo: Fermi National Accelerator Laboratory)

Ferrets have a long history of being put to work. They've been used to hunt rabbits and for vermin control, but perhaps their most interesting gig has involved running wire.

The animals' ability to navigate through confined spaces has been beneficial to several businesses and big events. Ferrets were used to lay cables beneath Greenwich Park for London's Millennium Concert, as well as to run wire at Buckingham Palace for the wedding of Prince Charles and Princess Diana. Boeing even once employed the critters to string wire through its planes.

In the 1970s, Fermilab's Meson Laboratory even used a ferret named Felicia (pictured above) to clean 300 feet of inaccessible vacuum piping, but eventually Felicia was replaced by a robot.

4. They Dance

When ferrets get excited, they'll often arch their backs, puff out their tails and hop about, a display commonly referred to as the "weasel war dance."

In the wild, weasels use this "dance" to confuse or disorient prey, but when domestic ferrets engage in the behavior, it's typically expressing enjoyment or playfulness. During such a display, ferrets will often make clucking sounds known as "dooking," and it’s not uncommon for them to lose their balance or to run into objects.

5. They Sleep Like the Dead

sleepy ferrets Don't wake me ... I'm recuperating from that last play session on the couch. (Photo: Vanessa [CC by 2.0]/Flickr)

New ferret owners might be alarmed to find their pet lying limp and motionless and not responding to touch or sound, but this is simply what's known as "ferret dead sleep."

"The ferret’s just in a very, very deep sleep," veterinarian Mike Dutton told Small Animal Channel. "Ferrets play very hard, and sometimes they really need that deep sleep to recuperate after all that activity."

6. They Can Be Trained

ferrets on leashes Once you get your ferret comfortable with a harness and leash, you can take them on a walk. (Photo: Hans Splinter [CC by 2.0]/Flickr)

Ferrets are intelligent animals with an incredible capacity for learning. They can learn to use a litter box, as well as how to sit, shake and walk on a leash.

7. They Love Packing Peanuts

Watch the video and you'll see just how much they love them. If you decide to try this with your own ferrets, specifies to use only biodegradable packing peanuts.

Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

7 things you didn't know about ferrets
Ferrets are adorable weasels that have impressive dance skills and an incredible capacity for learning, and they've even been employed by the royal family.