The protagonist of the movie is Max, who enjoys a wonderful life with his owner Katie until Duke's arrival changes everything.

Chloe is a plump feline who lives a few floors below Max in the same building and is generally indifferent to everything except finding a delicious treat to eat.

Despite Chloe's attempts to eat her, Sweetpea, the sweet and small Parakeet, enjoys socializing with the other pets and being a part of the party.

Runty is a brown and white hamster who has one of the most interesting names.

Leonard is the party animal of the apartment complex. Despite his calm demeanor, he is a heavy metal enthusiast who takes charge of the sound system to get the party started.

Despite being responsible for walking the neighborhood dogs, Guillermo is somewhat forgetful and fails to notice when Max and Duke go missing.

Despite being eager to make new friends at the dog park, this brown and white Papillon is unable to interact with other dogs due to his leash.

Nitro, Ozone's accomplice in the Flushed Pets gang, exposes Gidget and her group as domesticated pets, distinguishing them from the other wild animals.

Ripper, resembling Hannibal Lector, serves as Snowball's primary bodyguard and maintains a silent presence throughout the animated film, donning a spiked harness and collar.

Mel's primary adversary is the squirrel, which seems to be the Eastern Gray species commonly seen in North America, and never misses a chance to provoke him.

A Flushed Pet member named Dragon exhibits deranged behavior and takes pleasure in risky ventures, frequently operating motor vehicles recklessly.

After growing too large, Derick was abandoned by his owner and now resides in the sewers of the Flushed Pets' hideout as a large crocodile.

Living alongside the Flushed Pets in the sewer are the Sea Monkeys, who attribute their regular flushing by owners to deceptive marketing.

Encouraged by pet revelers, a cheerful Boston Terrier is chugging from a toilet.

As his owner is absent, Pops, an elderly Basset Hound, assumes the role of party host. He can only move with the aid of a two-wheeled harness fastened to his hind legs.

One of Guillermo's pets, an ocean-blue iguana, assists the neighboring animals in gaining entry to his balcony.

As Duke reminisces about his previous owner, we are shown a glimpse of him as a puppy, and it's evident that he was an adorable fluffy ball.

While walking on the street, a little girl spots Snowball and his gang and requests her mother if she can adopt them. Snowball, however, is caught and ends up becoming Molly's new pet.

Chloe's owner seems to be a woman in her middle age. She finds it difficult to pick up the chubby Chloe, much to the disapproval of Chloe.

The owners of Gidget seem to be a contemporary couple who reside in a stylish apartment.

The owner of Gino is a small boy with blond hair who greets Gino enthusiastically by kissing his fishbowl.

Max's beloved owner, Katie, introduces him to a new brother named Duke, and this sets off a wild adventure in The Secret Life of Pets.

Pepe is an enthusiastic Chihuahua with wide eyes who accompanies the group wherever they venture. His energetic and lively nature is contagious.

Throughout the movie, Gino, the goldfish, makes occasional appearances and can be seen casually swimming in his fishbowl, minding his own business.

In the opening scenes, we catch a glimpse of an apartment teeming with mischievous cats engaging in various activities.

Norman, a cute but bewildered guinea pig, is perpetually lost and unable to locate his home in the apartment complex.

Guillermo becomes intrigued by a redheaded girl, causing him to lose focus on his responsibilities as a dog walker.

Another dog enjoying himself in the dog park joins in with the other dogs in a frenzy to chase a butterfly when they spot one.

Initially appearing cute, this small blue kitten reveals a darker side by assaulting Max and severing his collar while he hangs suspended in the air.

Gidget's favorite telenovela program, La Pasion de la Pasion, features Maria as its female protagonist.

Despite his innocent and charming appearance as a cute white bunny rabbit, Snowball is actually the conniving mastermind behind The Flushed Pets, an underground gang.

Despite his intimidating exterior, Tiberius is a compassionate character who resists the urge to consume his fellow pets and instead assists them in their quest to locate Max.

The sewer scenes offer a glimpse of numerous deserted pets, known as the Flushed Pets, who have formed a gang seeking vengeance against humans.

Initiating new members into the Flushed Pets is the responsibility of Viper, a daunting red serpent of considerable size.

Similar to Pepe, Peanut is a petite Chihuahua who attends parties and captures all the excitement using his head-mounted GoPro camera.

Max and Duke attempt to plead with him for a bite of his sandwich, but he impolitely stuffs it into his mouth and hastily departs.

During their time at the sausage factory, Max and Duke experience a dream sequence where miniature sausages come alive and sing "We Go Together" from the Grease soundtrack, numbering in the thousands.

Reginald is the newest addition to Duke's former home, and his family has recently moved in following the passing of his previous owner.

Buddy's family consists of a young boy and his parents. Upon their arrival home, Buddy hides and then gleefully startles them.

Norman's owner is a cute little boy who appears sad when Norman goes missing. When Norman reappears, the boy is filled with joy.

The owner of Tiberius is an elderly man with a hunchback, thick glasses, and a cane. He expresses happiness when Tiberius visits him.

Max's adorable Pomeranian neighbor, Gidget, has a secret crush on him and takes charge of the local pets' mission to find him.

Mel is a small, hyperactive Pug with a strong aversion to squirrels. He firmly believes that they have malicious intentions and is wary of them.

Shelly, the cheerful turtle, appears content living in a small bowl with a palm tree, but also enjoys joining in the numerous parties hosted by the pets at Pop's house.

Buddy is a serene and relaxed Dachshund, also known as a Weiner dog, with a long and slender build.

Duke, the shaggy brown dog, is the primary co-star in the movie, embarking on a thrilling adventure with Max off the beaten path.

A lovely brown poodle was already present in the park when Max and his group arrived.

Ozone, an alley cat, exudes Pink Panther vibes and serves as one of the Flushed Pets' henchmen, assaulting Max and Duke.

The animal control workers are continually scouring the streets for stray animals, but all the creatures are opposed to their presence.

The male protagonist of Gidget's preferred telenovela series, La Pasion de la Pasion, is Fernando.

Tattoo, who was once a property of a tattoo parlor, is now one of Snowball's key henchmen, operating in the sewers with The Flushed Pets.

To gain access to the sewers, one must provide a password to the entrance guarded by snakes with red glowing eyes.

Snowball refers to Ricky as the late duck soldier who was the sole member of the troop willing to attack humans without hesitation.

During Snowball's eulogy for Viper, a curious little Piranha makes an appearance and attempts to flee, but Snowball grabs him for a hug.

Myron serves as Pops' assistant or butler and assists him with menial chores such as lifting his eyelids and providing a fan during hot weather.

At the top of the apartment building where many of the pets reside, Dummy stands watch over the ramp.

As Duke reflects on his past owner, a glimpse of him as a puppy is revealed, undoubtedly a charming little bundle of fur.

The new owners of Duke's previous home are frightened by his loud barking.

Mel's owner is an older man who works long hours, but upon seeing Mel eagerly waiting for him, he becomes energized.

Sweetpea’s owner is a man in his 30s with a rock-and-roll look who feeds Sweetpea by putting birdseed on his own bald head.

Steve, the owner of Pops, has a tall and slender build with a ginger red beard and mustache. He often wears a hat that resembles that of a detective.