[Long text] Interesting animals: rats! (rattus norvegicus)

Hello, a few months ago I did "Ciekawe Zwierzęta" series on Mastodon, they were exclusively in polish, though. So I salvaged the first text and translated it to english, so you all can see why a person such as myself loves rats so much. Enjoy.

Today's animal: common rat (rattus norvegicus)

Let me start with a linguistic fact that haunts me since I found out about it - well, in english language, a group of rats is called "mischief", which is absolutely hilarious - because it fits very well.

Rats have always been a great threat to humans due to their remarkable cunning, hard, iron-rinfused teeth that can easily cut through wood, cement, brick and metals likes of copper, aluminum and lead, the ability to breed quickly, and a fairly high social culture, which made dealing with rat infestations lose effect quickly, once the mischief realized that something was wrong with the food and avoided the probable sources of peer's misfortune. An additional factor adding to the difficulty is that, unlike mice, rats are neophobic i.e. they are sceptical and generally don't trust anything new. As a result, for example, it is difficult to encourage a rat to change the previously served food, but also force it to eat poison. Clever buggers.

Feeling threatened, rat groups migrate out, but keep their eyes and scouts on the place they previously inhabited. When the danger is gone, they migrate back in. And the circle closes.

Legend says that this is how the breeding of rats as pets began, in 18th-century England, at the court of Queen Victoria, during a huge infestation of rats that effecively meant they were everywhere, a particularly shrewd rat-catcher saw a business opportunity there and started taming what he considered more nice, trusting and friendly individuals. He would them pack them in small cages and sell them to people interested in such pets, saying that they were exotic animals from Norway. Hence the common name of the tame rat - which is a species of "rattus norvegicus", which can now be found all over the globe. (Well, with few exeptions, namely Alberta, Canada and Syberian north)
The domesticated rat of today lives on average for 3 years, in comparison to the ones living in wilderness, spanning just 1 year due to the high predator activity.

There are many reasons for rats to overcome difficulties and thrive everywhere. They are a highly specialized species. They can climb, jump and swim perfectly. They do great in sea and air conditions - e.g. by nesting in less accessible parts of planes or ships. A single rat itself has many tools and evolutionary freatures that allow it to survive and thrive in many environments - especially close to humans.

In general, I believe that animals from the so-called "trash animals" - that is, those that feed on the remains of human activity, are animals that somehow broke out of the food chain and overcame it. Think about it - in cities, apart from cats, there are practically no predators when people are not taking action to remove infestation. Aside from that, rats have very flexible bones that allow them not only to get through almost any crack, but also to absorb falls and mitigate the impact of hits and blows. Rats, however, tend to avoid fighting, even though they can fight and defend themselves and are a great threat when numerous, most rats will always prefer to run away compared to putting themselves at risk of being injured in a fight. They are adapted to this because even a rat's skull can bend due to the temporal bones being very flexible. As a result, the rat is fully able to squeeze through gaps that are only 1/3 of its width. Their highly specialised tails allow them to hold balance perfectly, which is useful for both climbing and running. In addition, rats do not sweat - so they don't leave a particularly strong smell, and regulate heat through the tail instead, which is why we can often see tails sticking out of hammocks and houses among domesticated rats at our households.

Heat exchange takes place by constricting and dilating blood vessels inside of their tails. Interestingly, rats often let more blood into their tails to add weight to it, turning it into ballast for jumping or risky climbing maneuvers. Another interesting fact about rats is that they have five fingers on their hind legs - which are called the jumping legs (by the way, they allow them to jump over a meter in height), i.e. with a very wide and long foot. Their front hands are very simmilar to humans; key difference being only four fingers, with which they are able to perform a variety of actions, from grabbing objects to pointing with their fingers. As far as I know, there is no scientific consensus as to why. Some theories I've read argued that the thumb used to be on the hands - especially since there's a little stump there - and getting rid of the thumb was supposed to make running and climbing easier. Other theories, however, insinuate that the thumb is still developing. Personally, I'm more of in favour of the former.

Rats boast a variety of incredibly well-developed senses, albeit limited by adaptation. Their vision is practically non-existent - even the best-sighted rat sees in shades of brown and gray at a very short distance. Their sense of touch is also lacking. Rats' senses shine in the areas of smell and hearing. The average rat has a much better sense of smell than a dog, which is why they are being used as searching animals for victims of collapsed buildings - for obvious reasons - a small rat will have easier time getting to a victim of said cataclysmic event.
During armed conflicts, they were also often used to detect land mines because, unlike dogs, they were light enough not to set them off. In addition, their taste is developed so strongly that they are able to recognize the slightest changes - which paired with their social relations and previously mentioned neophobia, makes poisoning a number of rats even more difficult.

Speaking of social relations, rats have more intricate relationships than some species of monkeys and apes. They are highly hierarchical beings, so there is always a singular rat that makes all of the rules.
In addition to the mischief leader, there is always a second-in-command, who maintains order when the leader is busy, absent or simply not in the mood to "govern". There are also a variety of outcasts and outspoken rebels which were observed defying the hierarchical structure of rat society.
Rats also don't leave their own to die and will always desperately try to help the wounded and attacked, even at the risk of their own lives. It is also very important in clashes between mischiefs. They are capable of a ceasefire agreement and cooperation to combat mutual threat, and always aid injured individuals from their ilk, even if it was previously a member of the opposing mischief. In addition, rats have specific roles that allow the mischief to survive by utilizing and developing their skills. They are assholes sometimes, working in extremely machiavellian ways, often sabotaging and subverting other individuals (in a bodily harmless way) to weaken their position in mischief and elevate their own. They are also conformists and as such, are easily peer-pressured into complying and due to well-developed "language apparatus", thanks to which they communicate with both tails and ultrasounds, they fall into arguments or pass information to each other constantly. For a rat, even in a small group there's a constant chatter. Also, they use their whiskers to show the size of the items they are "talking about" and warn others.

A domestic rat must always have at least one partner, because even though, due to the very strong need for socialization, human is often accepted as one of their own and becomes the part of the mischief, humans are not able to provide what another rat can - that is, hugging, "grooming" and games - such as hide and seek or tag. A rat without a companion usually physically dies of loneliness. This creates a very interesting dynamic, because despite being absolute worst to each other, rats need others to literally survive.
Sounds familiar, right? Really rings a bell.

Contrary to stereotypes comprised mostly of lies, rats are notoriously clean animals. They care about cleaniness to the point that they literally wash themselves and each other about 1/5 of the day. If you touch a rat, it will wash itself thoroughly at the first opportunity it has. As a result, the smell of rats is generally very nice and pleasant, and their fur is always fluffy to touch. I really recommend you all take a chance to try it - just this once - if the opportunity arises. They are also very curious, trusting and extremely intelligent animals, but if you aren't convinced already, just see it for yourself:

https://yewtu.be/watch?v=0jo_EG7XqZQ
(YT Link: Amazing Rat Tricks 1)

https://yewtu.be/watch?v=7g2rxtWu_FM
(YT Link: Amazing Rat Tricks 2)

To wrap it up, a fun fact.
Rats generally dream dreams while sleeping, and part of the dreams they dream are nightmares. If that occurs, a member of mischief will always watch over a traumatised one and cuddle them.
They are capable of feelings such as remorse and grief associated with losing something, humiliating or hurting another rat or human.
They can also feel sadness and joy.

I hope this makes you feel somehow sympathetic towards these beautiful little buggers.
English is not my main language. In case of outrageous mistakes, please correct me.