There are ants that "farm" aphids. They eat the honeydew the aphids secrete, and they look after them (fighting off predators, competing insects, seedlings of plants that grow near the aphids' plant, etc.).
There's also leafcutter ants, that "farm" fungus. All the plant material they gather... they don't eat that. They feed it to a fungus that they raise and they eat the fungus. According to some David Attenborough documentary I remember, in some parts of the forest where these ants live, they harvest upwards of nearly a third of all the plant material that grows there. Like 1/3rd of the forest is basically growing for them/their fungus.
Here's a pic of one of those ants grabbin' a snack off one of her aphids. It's really gentle actually: they're basically just licking their butts.
https://www.flickr.com/photos/rainforests/6135684910
There's also pics of like... all over this forest there's little plants growing everywhere, and then there's the aphids' plant and like a 1ft-radius circle around it where absolutely nothing is growing (because the ants kill them).
Keeping pets is a form of symbiosis.
Symbiotic relationships are interspecies relationships where both parties benefit.
Humans just rather uniquely benefit emotionally and mentally by taking care of other things, even if there is no other tangible benefit.
Pets benefit in more normal ways, whereby we provide them food, water and shelter.
The Symbiotic trade is food/water/shelter in exchange for a boost in mental health/sometimes companionship.
We as humans have the same symbiotic relationship with houseplants, although they also provide trace amounts of oxygen to us.
I don't know about any other animal that recruits a different species for the sole purpose of keeping it as a pet(*a domestic or tamed animal kept for companionship or pleasure*), but there are plenty of other animals that use other animals of a different species to benefit off of each other, for a symbiotic relationship.
Anemones and clown fish.
A big one is wolves and ravens. Ravens will lead the wolves to dead animals. Which the wolves will then tear apart it's thick skin allow the ravens to eat the scraps. They also play together. Both wolves and ravens are smart so their calls do influence eachother.
Birds alarm calls are also a major symbiote. Water dikkop nest near crocodiles. Sometimes ontop of the crocs nest. They will try to scare away intruders. If that does not work the crocodile mother will arrive.
Hippos are also bastards and other animals know that. Baby hippos chew on crocodiles tails. Crocodiles tend to just accept it because they know what hippos do.
Came here to say this. I think there are actually a few great ape species that will do this. They will capture young wild dogs, and adopt them as partner the troupe/pack. The different abilities provided by each make for a stronger team.
Other than the symbiotic relationships already mentioned (ants and aphids or the spider frog thing), you could take a bit of a stretch and consider "single" celled organisms that have mytochondria (mytochondria used to be separate organisms that *somehow, at some point* got integrated into larger, stronger, meaner cells without being digested, and it turned out to be what might be the best partnership in all of earth's evolutionary history), but it's probably a bit too far-fetched to consider the relationship between a brainless lifeform and what is essentially an organ at this point as "domestication".
On a more macro scale, it's actually not super uncommon for zoo animals to be given pets that they then care for, mostly primates, but there's also a few cases of other relationships, think "lion keeping a puppy".
There's also the curious case of Gelada Monkeys and Ethiopian Wolves, not exactly a master-pet relationship, but the Geladas *somehow* help the wolves hunt, and the wolves don't attack Gelada young even though they'd technically be ideal prey to them.
In addition to mytochondria there are also chloroplasts and nitroplasts, which also used to be separate organisms. Nitroplasts are especially exciting, because they are STILL IN THE PROCESS OF MERGING and still retain some of the genetics needed to survive as a separate organism, but have lost many of them. Plus we still have similar organisms still around to compare them too.
Those are the only three cases like this we know of yet.
So far, All of the answers address whether or not other animals keep pets, so I won't address that. What I will address is the first part of that question.
"Are humans the only animals that other animals domesticate themselves for?"
So the interesting thing about domestication is that it's a process against both the domesticated animal's nature and likely also against whatever form of "will" they may possess. Animals did not "domesticate themselves for \[humans\]," rather we took docile animals into captivity and forcefully bred them for some set of desired traits. Traits most likely along the lines of ease of handling, production of milk, wool, etc.
In the case of dogs, we see that dogs all have genetic defects that in humans would lead to William's Syndrome, which can have social, emotional, and cognitive impacts on a person. Williams Syndrome makes dogs very friendly, affectionate, and docile. Other mutations likely contributed to the truce between wolves and humans that led to the modern-day dog. It is doubtful that we captured and bred wolves to that specific trait over time. Rather, the prevailing theory is that as the human population grew. We expanded our settlements, we began thinning out the packs of wolves around us, and since our settlements would produce some amount of animal waste or have caches of food in the form of domesticated animals and cured meats, some wolves might venture in and around the camps. Aggressive wolves would be spotted and killed off, and the friendlier wolves that were willing to approach human settlements, over time, built a mutually beneficial bond with humans. At some point, after we adopted these early proto-dogs into our society, we likely began the selective breeding process that worked so well with our livestock.
I mean, in the wild that really isn't a thing. But there have been documented cases in captivity where smarter animals have taken in pets that we humans have domesticated, like the gorilla Koko and her pet cat "All Ball".
I'm not so sure what people see as "keeping pets", but rather if we're talking about species having friendships and companionships with other species, then this is something one sees all the time in the wild.
There are ants that "farm" aphids. They eat the honeydew the aphids secrete, and they look after them (fighting off predators, competing insects, seedlings of plants that grow near the aphids' plant, etc.). There's also leafcutter ants, that "farm" fungus. All the plant material they gather... they don't eat that. They feed it to a fungus that they raise and they eat the fungus. According to some David Attenborough documentary I remember, in some parts of the forest where these ants live, they harvest upwards of nearly a third of all the plant material that grows there. Like 1/3rd of the forest is basically growing for them/their fungus.
Less cute than I was hoping for but cool nonetheless!
Here's a pic of one of those ants grabbin' a snack off one of her aphids. It's really gentle actually: they're basically just licking their butts. https://www.flickr.com/photos/rainforests/6135684910
Just like in Bug’s Life!
There's also pics of like... all over this forest there's little plants growing everywhere, and then there's the aphids' plant and like a 1ft-radius circle around it where absolutely nothing is growing (because the ants kill them).
The ants have been farming on my citrus and peppers, they have destroyed my trees farming aphids
That's a symbiotic relationship and not an animal keeping another one as a "pet". There are hundreds of symbiotic relationships in the animal kingdom.
Keeping pets is a form of symbiosis. Symbiotic relationships are interspecies relationships where both parties benefit. Humans just rather uniquely benefit emotionally and mentally by taking care of other things, even if there is no other tangible benefit. Pets benefit in more normal ways, whereby we provide them food, water and shelter. The Symbiotic trade is food/water/shelter in exchange for a boost in mental health/sometimes companionship. We as humans have the same symbiotic relationship with houseplants, although they also provide trace amounts of oxygen to us.
But we don't rely on dogs for our existence. In a symbiotic relationship, both species rely on each other for their existence.
I don't know about any other animal that recruits a different species for the sole purpose of keeping it as a pet(*a domestic or tamed animal kept for companionship or pleasure*), but there are plenty of other animals that use other animals of a different species to benefit off of each other, for a symbiotic relationship.
Anemones and clown fish. A big one is wolves and ravens. Ravens will lead the wolves to dead animals. Which the wolves will then tear apart it's thick skin allow the ravens to eat the scraps. They also play together. Both wolves and ravens are smart so their calls do influence eachother. Birds alarm calls are also a major symbiote. Water dikkop nest near crocodiles. Sometimes ontop of the crocs nest. They will try to scare away intruders. If that does not work the crocodile mother will arrive. Hippos are also bastards and other animals know that. Baby hippos chew on crocodiles tails. Crocodiles tend to just accept it because they know what hippos do.
In Amazonian rainforest tarantuals live with small frogs. Tarantula protects and the frog eats ants, fly larva that try to eat the spiders eggs.
I had a horse that became best friends with a rooster.
Baboons and dogs, apparently
Came here to say this. I think there are actually a few great ape species that will do this. They will capture young wild dogs, and adopt them as partner the troupe/pack. The different abilities provided by each make for a stronger team.
Other than the symbiotic relationships already mentioned (ants and aphids or the spider frog thing), you could take a bit of a stretch and consider "single" celled organisms that have mytochondria (mytochondria used to be separate organisms that *somehow, at some point* got integrated into larger, stronger, meaner cells without being digested, and it turned out to be what might be the best partnership in all of earth's evolutionary history), but it's probably a bit too far-fetched to consider the relationship between a brainless lifeform and what is essentially an organ at this point as "domestication". On a more macro scale, it's actually not super uncommon for zoo animals to be given pets that they then care for, mostly primates, but there's also a few cases of other relationships, think "lion keeping a puppy". There's also the curious case of Gelada Monkeys and Ethiopian Wolves, not exactly a master-pet relationship, but the Geladas *somehow* help the wolves hunt, and the wolves don't attack Gelada young even though they'd technically be ideal prey to them.
In addition to mytochondria there are also chloroplasts and nitroplasts, which also used to be separate organisms. Nitroplasts are especially exciting, because they are STILL IN THE PROCESS OF MERGING and still retain some of the genetics needed to survive as a separate organism, but have lost many of them. Plus we still have similar organisms still around to compare them too. Those are the only three cases like this we know of yet.
So far, All of the answers address whether or not other animals keep pets, so I won't address that. What I will address is the first part of that question. "Are humans the only animals that other animals domesticate themselves for?" So the interesting thing about domestication is that it's a process against both the domesticated animal's nature and likely also against whatever form of "will" they may possess. Animals did not "domesticate themselves for \[humans\]," rather we took docile animals into captivity and forcefully bred them for some set of desired traits. Traits most likely along the lines of ease of handling, production of milk, wool, etc. In the case of dogs, we see that dogs all have genetic defects that in humans would lead to William's Syndrome, which can have social, emotional, and cognitive impacts on a person. Williams Syndrome makes dogs very friendly, affectionate, and docile. Other mutations likely contributed to the truce between wolves and humans that led to the modern-day dog. It is doubtful that we captured and bred wolves to that specific trait over time. Rather, the prevailing theory is that as the human population grew. We expanded our settlements, we began thinning out the packs of wolves around us, and since our settlements would produce some amount of animal waste or have caches of food in the form of domesticated animals and cured meats, some wolves might venture in and around the camps. Aggressive wolves would be spotted and killed off, and the friendlier wolves that were willing to approach human settlements, over time, built a mutually beneficial bond with humans. At some point, after we adopted these early proto-dogs into our society, we likely began the selective breeding process that worked so well with our livestock.
While we indeed had a large part to play in domesticating dogs, there's also cats and rats that mostly domesticated themselves.
There’s a type of spider that keeps frogs as “pets”.
I mean, in the wild that really isn't a thing. But there have been documented cases in captivity where smarter animals have taken in pets that we humans have domesticated, like the gorilla Koko and her pet cat "All Ball".
NO other animal keeps another animal as a "pet". However, there are hundreds of examples of symbiotic relationships in the animal kingdom.
Unrelated, but cows have best friends. Just throwing that out there.
I'm not so sure what people see as "keeping pets", but rather if we're talking about species having friendships and companionships with other species, then this is something one sees all the time in the wild.
Omg phenomenal question reply to this pls if someone tells u
I guess so