I think, but am not certain, that it may have been Nature’s End by Whitley Strieber and James Kunetka. Genetic engineering and intelligence-uplift of domestic animals was an important plot point.
I hug your arm
I really hug your arm
I bite down hard on your arm
I couldn’t love you any more
You couldn’t be any more confused
It’s fair to say we have a relationship that is
complicated
From “I Could Pee on This and Other Poems by Cats”
Well just change cat to dog and substitute Great Dane and you have your answer. 
I grew up with this “gentle giant” and they are great pets but they can do damage without even knowing. One happy great dane wagging his tail can easily knock over a toddler or even a small grade school child.
Once we had a 10 pound housecat that hated me. One day he sunk his teeth into my right wrist and refused to let go. I had to dunk him under water to get lose. I still have puncture wound scars from that episode.
If he had been the size of a lion…
Cats have been truly domesticated, assuming you even accept that, for a far shorter time than dogs. Having cats in the house is pretty new. Anyway just as lay dog and cat lover (cats when growing up, dogs with my kids and now that they’re grown up) I wouldn’t have even a 60lb (athletic) cat like I have a 60 lb athletic dog, let alone a lion size cat. Some cats are as friendly and human oriented as some dogs, but the averages are far apart. Some people worry in the abstract about dogs like mine (‘pit bull’ type), but in the concrete most dogs are doglike: the idea of harming a human, who isn’t torturing them or something, is alien to them at a deep level. Not as true with cats that I’ve known, even cats I liked. Glad they were small.
I am friends with two different, well-cared housecats that take down adult European hare (average live weight 10 lbs., top speed 50 mph) when they feel like it.
Yes. Very dangerous. Much as I love cats, a pet that size could not be trusted. A gentle giant cat could decide to be playful and then watch mystified as you bleed quietly away.
Dogs are different.
I would imagine that if you had a housecat that were size of a lion but possessed the general behavioral characteristics of a housecat, uttering the simple words “bath time” would unquestionably result in near-instantaneous death.
If you are going to scale up a domestic cat to the size of a lion you will have to scale up his muscles as well to hold a larger frame.
Our family cat was a terrible bird and rat killer but he was also best friends with the family pet rat, rabbits and quail I used to keep. ( we did have a couple of slips on the quail but he soon learned they were off limits). I think a cat would behave much like a domestic version of a leopard.
I’m a long-time cat owner and have had many cats. What concerns me about the giant cat scenario is that my cats don’t seem to know the difference between hunting and playing. My cats are well-fed, but they often drag a mouse, cricket, frog, etc., into the house and bat the poor creature around until it’s dead. The cat obviously thinks this is huge sport.
If the cat were bigger than me, I suspect I would become a toy/prey, even if the cat did not intend to hurt me.
When I was a kid we had these barn cats in the place where I kept my horses. They were totally feral. Not at all friendly.
So one day I came in the barn and a bunch of kittens and their mother were feasting on the remains of a rabbit. When I approached them they all ran away, except one white kitten. I thought, “ah, that one is tame! I will pick it up and pet it, and maybe take it home!” So I picked it up.
Young kitten. Probably weighed two pounds. Uh, I had to drop that cat within about five seconds, and I had scratches. And blood. Some of it was rabbit blood and some of it was mine.
That kitten was not tame–that kitten was deaf. And hungry. It had not heard me approach. When its mother and littermates left it probably thought, “Hey more for me.”
So, just based on that little kitten, I would say a lion-sized house cat would be just as bad as a lion.
I think there is a very good reason that dogs can be great pets at all sizes but cats stay comparatively small.
Now I guess some lions who are raised by someone from birth can be trusted not to kill you. I wouldn’t bet my life on it though.
Some people tried this. Did not end all that well.
1981 movie “Roar” - This has to be the most insane film ever made!
Nice kitty… nice kitty… nice kiAaaaaaaaaaaghohnogetitoffmegetitoffmeOhmyGodnoooooooooo!
[quote=“Shagnasty, post:5, topic:769223”]
I don’t see any real difference between house cats and lions or tigers other than their size as long as they are well fed and have become habituated towards people. As a matter of fact, a house cat the size of a lion or tiger would probably be much more dangerous. I have had them go psycho and attack me suddenly for no reason so many times that I have lost track. That isn’t so bad when you can just pick it up and throw it across the room when it lands on your face but it is really bad news when it weighs many times more than you do.
Here is a video of people playing with some of the biggest cats in the world including lions, tigers and ligers (the biggest cat hybrid in the world). I have met lots of house cats that I trust a lot less than any of those.
[/QUOTE]I am seeing a bit of confirmation bias in your conclusion that domesticated cats would inherently be more attack-prone than well-fed & habituated lions/tigers.
A pet tiger/lion that attacks people would either be unreported by the owner (if the loving owner was the victim), or be gotten rid of from the house as an unacceptable danger. Domestic cats that occasionally attack can/are tolerated to a certain degree since the damage is usually not life-threatening, and the owners do not tend to feel stigmatized about letting others know about the attacks (you seem to personally know such cat owners). It reminds me how there are chihuahua owners out there that let there ill-tempered tiny dogs breed more ill-tempered tiny dogs because the owners are tolerant of the (relatively) small damage such nasty little gremlins can inflict compared to a bigger dog.
Bottom-line, lions/tigers are not inherently less likely to attack when raised to the same standards as a domestic cat.
One thing about domestic cats - as noted - they occasionally go nuts.
Why is another matter. There is no good reason for it, and I have never heard of a big cat being observed going nuts, and I suspect feral cats don’t either. Rather (again I suspect) domestic cat behaviour with humans is due to a weird middle state of development with us.
There a range of theories on why you get sudden changes in mood. Rubbing a cat’s tummy, it is surmised, may be pleasurable for a while, but may turn painful for the cat. But IMHO that is simplistic. When you get to know a cat very well you can tell when it is about to snap.
One of my cats will bite my hand occasionally, but if one watches the behaviour carefully (which one may not be quite in the right mood to do with a cat sinking its teeth into you) I realised it was not attempting to do harm, but was actually engaging in a preening behaviour akin to where it gnaws at its own fur during cleaning. Had I been a kitten with fur, I would merely have been getting a good clean. Cat was in “you are my kitten” mode, and was trying to look after me.
Other times of course the evil critter has just been is a belligerent mood and bit me for giggles.
A bigger version of this behaviour could be, well, worrying. It is possible that domesticated big cats are actually better behaved. Always wanted a pet tiger. Useful to keep neighbourhood pests down. Silly yappy dogs, noisy children, and so on.
I wouldn’t want to scoop the litter box of a cat that big.
Well if you had a lion-sized housecat you better always have a laser pointer on you that way if he started acting weird you could distract him with that or you know point it at people you didn’t like so much.
I think the muscles probably pretty much come with the size - that is to say, in order to scale up a cat to the size of a lion, it would be necessary to change the skeleton and musculature a bit, or the thing simply wouldn’t work - the old square-cube law.
If we were trying to scale a housecat to be 40 feet long we’d have a real problem with square/cube.
The fact lions & tigers exist proves the basic feline design works at that scale. Yes, the proportions of a full-grown lion and a scaled up equivalent-weight housecat would be different. The house cat will have thinner longer legs. Which won’t work, or at least not work as well.
In this case we’re dealing with tweaking a design, not revamping it completely.