Kanwut March started the Mechanicat species, or at least coined the term. Kanwut is a man who is cocky and blunt and selfish but rather helpful(If your definition of 'help' includes inventing things that really aren't necessary but work), and impossible to anger, he was a great(Although sarcastic) adventurer from his early 20s all the way up to his late 50s. One day, Kanwut(58 years old) found a temple surrounded by tiny pyramids and stonehenge structures, it had never existed in all of history, yet he could see it so he and his wife(Also an adventurer) decided to venture into it, suddenly a bright light stunned him and he awoke on an ancient-looking stone operating table smelling blood, and surrounded by weird creatures, then he spotted his wife on another stone table with aliens covering her up as if she were dead, he was too dazed however and didn't think much of it. When the aliens threw him out, he heard(And felt) a metallic clang from his shoulder(Muffled by the fabric of his explorer jacket) as he hit the ground, and that's when he realised his torso had been replaced by metal, he paced around unsure of what to do, and wondered where his wife went, then his childhood friend, Holly, approached him and offered him a job as a scientist at Sparrow Industries, and he accepted. Later, when the new laboratory was being set up, Kanwut noticed his childhood friend wasn't acting like herself, and then a year later the aliens took her and never returned, leaving Kanwut to run the new laboratory on his own, and he had a big weight on his shoulders and chest when he came to the realisation that he may never see his wife again.
In his struggle to keep the laboratory running, he randomly said one day "I think we need a robotic servant.", the scientists laughed but considered the idea, and begin working on a prototype, before Kanwut cancelled the operation saying "It's hopeless. We had better keep realistic expectations, what's our robot going to do when it isn't being told what to do?".
A year later, the laboratory was surviving(Though not thriving) as it manufactured various different technology devices. Kanwut spent time writing a story and pondering that day in the weird temple, and he remembered those beings were aliens. He spent a day writing down the events of the last temple exploration, and piecing things together until he came to the realisation that his metal torso must be made of alien technology... So he ran some studies. This was an ingredient of the Mechanicat species.
Kanwut found alien technology, but the scientists thought that it wasn't a good idea to use such technology in laptops or phones. One day, he remembered Oleander, her liking of cats and robots, and her dream of there being a robot cat. At this moment, Kanwut knew the stage was set, the time was now, he planned to start work on a prototype of a robot cat, and better yet it would be sentient!
7 years later, now that Sparrow Industries was rich, work began on prototypes(Gui's siblings). Kanwut was 67 years old.
The first prototype Mechanicat just wouldn't come to life, a year later they created again but the second one died, yet another year later the third one was made but then incinerated due to malfunction, but still Petrel Industries tried again. Two years later, the fourth and fifth were created but both malfunctioned and were marked for slaughter, the scientists tested the pain sensing of the fifth(To find out what hurts robots), before fourth and fifth both escaped via an escape route no scientist knew existed, and it made Kanwut wonder if Mechanicats were getting too smart, but he was confident that they'd have a tame Mechanicat someday. That same year, the sixth was created and was about to escape when a scientist pummelled the robot and threw it into the incinerator, since it was marked for slaughter too... Petrel Industries is quite brutal at times, but Petrel Industries prides itself in owning only friendly sentient machines to introduce sentient machines to the public, so some robot sacrifices have to be made. Still that year, the seventh one was also malfunctioning and was pummelled, but escaped anyway.
Finally, after all those years, they made a successful Mechanicat. It's 2017 and Kanwut was 70 at the time.
The first known successful Mechanicat was Gui, as far as Sparrow Industries' knowledge went, and Gui was made to replace animals that are used for fur, somehow that was the drive the scientists needed to actually get something working properly... Well, Gui's AI systems were in good working order, but Gui wouldn't grow fur on her own, the scientists had taken off most of her fur in the experiments they ran trying to get the fur growth mechanism to work, her fur growth mechanism was still not functioning when she escaped the lab following an accident involving a wrecking ball, which had caught her tail and caused permanent damage to her left eye's red hologram, and then after a few mishaps where she threatened to eat lions, she was captured by the rebuilt Sparrow Industries and re-purposed to protect organic beings and fight the robots that the scientists thought were coming, but the supposed incoming robots never came so they chose to finish the creation that they had rushed to create. The laboratory named ShadowFault Industries took note of the creation of sentient robots, and laughed because they had made sentient spaceships long ago! ShadowFault Industries wasn't a villain however, they became friends with Sparrow Industries.
More and more different tech manufacturers are making their own Mechanicats, each Mechanicat is made to the liking of their manufacturer, they can be built for any task and even rebuilt completely if the manufacturer so desires. If there are any problems, then any nearby being is advised to alert the manufacturer via radio, be it their own radio or the radio built into the Mechanicat.
Gui's manufacturer, Sparrow Industries, thought Sparrow wasn't unique enough, so it got renamed to PetrelBrow Industries.
According to the studies of the inner workings of some Mechanicats, scientists estimate Mechanicats to have a lifespan of 4-60 years(Differs for each Mechanicat), in very rare cases they may last just one year. After reaching their maximum age, they start to wear down and quickly become more and more prone to malfunctions until they lose their ability to function at all, it usually takes just 5 days for the wearing down to complete after it starts, the medic can do nothing to save the Mechanicat who's worn away.