Happy National Ferret Day! In honor of the holiday, brush up on your knowledge about everyone's favorite (and longest) pet. 

1. Ferrets have been domesticated for a quite a while. 

It is unclear when ferrets were first domesticated, but the critters have a long and storied history. Greek scholars—Aristophanes in 450 BCE and Aristotle in 350 BCE—wrote about a ferret-like animal. Some lore asserts that ancient Egyptians even kept them as pets, but the absence of ferret bones in explored tombs casts doubt on that claim. Remains have been found in a medieval castle in Belgium, but there is no mention of the pets in any contemporary writings. It's also possible that the ferret was exclusively a lower class pet, which would explain the lack of documentation. 

In the late 15th century, Leonardo da Vinci painted Cecilia Gallerani holding a weasel-like creature. Although the animal has been dubbed an ermine, many scholars believe the animal is actually a ferret. 

2. They are related to polecats. 

Ferrets are the domesticated subspecies of European polecats. They can easily interbreed to produce offspring that’s very similar to domestic ferrets.  

3. When threatened, ferrets will dance. 

In the wild, ferrets and stoats perform a hypnotic dance that sends their prey into a trance. Domestic ferrets also perform this dance, but they use it for play instead of hunting. They arch their backs, puff their tails, and move from side to side. This rug-cutting is usually a sign that the ferret is happy and having fun

4. Black-footed ferrets almost exclusively eat prairie dogs.

Wild black-footed ferrets, or American polecats, live in central North America and feast on unsuspecting prairie dogs. Scientists discovered that in South Dakota, 91 percent of the black-footed ferret's diet was prairie dogs [PDF]. 

Unfortunately, their main source of food has bigger problems than being eaten: The Black Death. The plague is no longer a worry for most humans, but it has a tendency to wipe out whole colonies of black-tailed prairie dogs. This threat is a real issue for the endangered black-footed ferrets, which perish without their favorite food. Luckily researchers have found a vaccine that could help keep the tiny rodents healthy. Testing is currently underway to see if the vaccine works in the wild. 

5. A group of ferrets is called a business.

Now that’s a professional pet! 

6. Ferrets can be used to hunt rabbits.

Rabbit hunting with ferrets is a popular sport in England. The ferrets run into rabbit holes to run the prey out of hiding. When the rabbits dash from their homes, human hunters trap them in nets. The tiny hunters wear ferret finder collars so if they corner a rabbit underground, their owners can come to their rescue with a shovel. One place you'll never see any ferret hunting:  Minnesota, where it’s illegal.

7. They can team up with falcons. 

Falconers employ ferrets in a similar role; the only difference is that the ferrets are used to bring the prey to the falcons. The two animals make a great hunting team.

8. Some ferrets have jobs. 

Known for their love of burrowing, ferrets can put their skill at running through pipes to a variety of professional uses. When wires cannot be pushed through tubes or tunnels with rods, the tiny critters step in. They are known for pulling wire through underground tunnels, and even helped lay wire for the millennium concert in London. 

One famous ferret named Felicia helped clean pipes at Fermilab's Meson Laboratory in 1971. A swab connected to her collar allowed her to clear away unwanted debris. Although Felicia only cost $35, she likely saved the lab thousands of dollars. 

9. This job led to a fun competition.

Ferret racing is a popular sport in London that involves competing ferrets racing through drainpipes. A small section of the pipe is removed and replaced with chicken wire so viewers can know when the pets are half-way through. Apparently, the animals thoroughly enjoy the race and company of their fellow ferrets. 

According to zoologist James McKay, the sport originated with ferrets being used to drag cables through pipelines in the desert. After a hard day's work, the engineers would use their downtime to race the employed ferrets through tubing.

10. Keep your babies away from them.

Ferrets are great pets for adults, but they should not be left around babies. Several reports have found that pet ferrets have attacked babies while the parents slept. 

Edgar K. Marcuse explained the phenomenon in the Journal of American Academy of Pediatrics

The animals seem attracted to babies, perhaps due to odors resembling those of suckling rabbits. Typically, attacks are made when parents are absent or asleep; the ferret escapes its cage and jumps into the baby's crib.

11. Scammers have sold ferrets on steroids as fancy poodles.

If you are looking to get a tiny exotic dog, make sure you’re not actually buying a ferret. In 2013, some Argentineans were being tricked into buying fake miniature poodles. Ferrets were given steroids and new haircuts before being passed off as exotic tiny dogs. The owners often didn’t realize they had accidentally bought drugged ferrets until visiting the vet for shots.  

12. Females can die if they go too long without mating.

Unspayed females need to mate or run the risk of producing too much estrogen. The overproduction can lead to estrogen toxicity, or hyperestrogenism. This condition can lead to anemia, clotting, and death. 

13. Ferret legging is a thing.

There is a "sport" called ferret legging and it is horrifying. The popular endurance game starts with a man with loose fitting pants. The ends are tied shut, and several ferocious ferrets are placed inside. The belt closes the top of the pants, and the game begins. The angry ferrets will bite and claw to try to get out and the player must endure the pain as long as he can. The current record is over 5 hours.

14. Scientists fiddled with a ferret’s brain and made a startling discovery.

In the 1990s, neuroscientists at MIT reconfigured baby ferrets' brains so that the critters' retinas were connected to their auditory cortexes. They expected the ferrets to go blind, but miraculously, they readjusted so that the auditory cortex worked like the visual cortex; they could see using the part of the brain normally used for hearing. This discovery showed that the brain is adaptable and makes use of what’s available. ''It's just waiting for signals from the environment and will wire itself according to the input it gets,'' said Dr. Jon Kaas, a professor of psychology at Vanderbilt University. 

15. They love to jump.

But sometimes they land in some unfortunate places.