No actual marriage has to even be shown. It can be an In Name Only title with no legal bearing (if the series even has laws). Animals will very often be considered "married" as soon as they become mates.
Marriage between animals is most prevalent in children's works and Beast Fables. Instead of being referred to as mates, animals will be referred to as "married". Often times this is shorthanded to by referring to them as "Mrs. [x]" and "Mr. [x]" (often using a Species Surname) in animal characters hailing from Anglophone countries, "Sra. [x]" and "Sr. [x]" (often with a Species Surname) in those hailing from Hispanohablante countries, or whatever their given country's language's equivalent is.
This trope can also explain the works with animal characters that have implications or explications of having out-of-wedlock births.
This trope can apply to polygynous and polyandrous marriages, but as polygamous marriages are illegal in most Western countries (except for South Africa) and polyandrous marriages are not widely accepted by many human societies, most trope examples are monogamous.
This trope applies to the Nearly Normal Animal, Speech-Impaired Animal, Talking Animal, and Partially Civilized Animal. It also applies to the somewhat anthropomorphic Civilized Animal. This applies to Funny Animal characters that are treated as the animals they are in the work's verse or are more Beast Fable in nature, but not to those treated as humans in-universe or those that have a Furry Lens on them. This doesn't apply to Beast Men, as they're usually treated on par with humans.
- Bunya the male cat and Noisy the female cat from the 2016 CGI Chi's Sweet Home, a work with non-anthropomorphic or barely anthropomorphic animal characters, are referred to as married.
- In All My Kittens, Duchess' owner refers to Duchess' stud mate as a "husband".
- The Bolt Chronicles: "The Rings" shows longtime sweethearts Bolt and Mittens have a private marriage-like ceremony later in the day after Penny and Joe's more traditional wedding. They even exchange rings by putting them on each other's ears.
- The geese twins from The Aristocats get mad at Thomas when they learn that he isn't married to Duchess. It's unclarified if Thomas and Duchess do ever marry, but the film ends with Thomas being adopted by Duchess' owner.
- In Dumbo, the mother elephant is named Mrs. Jumbo. Although the name suggests she's married to a Mr. Jumbo, he's not mentioned in the film, and her son is brought by a Delivery Stork.
- One of the main characters in Home on the Range is a Partially Civilized Animal cow named "Mrs. Calloway". There's never any mention of a "Mr. Calloway" though.
- Lady and the Tramp: Lady's friends, Jock and Trusty, offer to marry her in case her owners kick her out.
- In The Lion King (1994) characters are not referred to as "husband" or "wife", but the concept of marriage still exists. Simba and Nala are mentioned to be betrothed to each other as cubs and the word "married" is even used. In real life lions are not monogamous, however all lions in the series seems to be. This leaves Nala's parentage all the more confusing, but allows the series to cleanly subvert Brother–Sister Incest or Kissing Cousins by not having Simba and Nala be related like real lion cubs from the same pride would.
- In 101 Dalmatians Perdita and Pongo get married along with their owners.
- At the end of The Princess and the Frog, Mama Odie gets Naveen and Tiana married, pronouncing them "frog and wife". Although they are humans in frog form, there are a bunch of Woodland Creatures attending the wedding, implying this is a normal ceremony for them.
- The Pevensies meet Mr. and Mrs. Beaver soon after entering Narnia in The Lion, the Witch, and the Wardrobe. They provide a brief respite, as well as some necessary backstory exposition.
- In Beware of Chicken Spirit Beast pigs Chun Ke and Pi Pa are referred to as husband and wife, both by each other and by the other inhabitants of Fa Ram. This is the only case shown of such a relationship between two Spirit Beasts, though they are also the only two Fa Ram Spirit Beasts of the same species.
- In the Cat Pack series, Timothy the mouse mentions that he has a wife.
- In The Cold Moons, badgers are referred to both as mates and spouses. It's even mentioned that they have a wedding-like ceremony.
- The mother of the winged cats in Catwings is called "Mrs. Jane Tabby".
- The children's book Dear Hound is about a Deerhound puppy who gets lost in the woods. He is helped by a pair of foxes, Sunset and her husband Fixit.
- InCryptid: Timpani recognizes that two Aeslin mice have mated because they've built themselves a house, and the female appears to be pregnant. She refers to their relationship as a mouse honeymoon.
- One of the first inhabitants of Narnia that the Pevensies meet in The Lion, the Witch, and the Wardrobe are Mr. and Mrs. Beaver. Beavers in real life form monogamous pairs for life.
- The widow protagonist of Mrs. Frisby and the Rats of NIMH Mrs. Frisby (renamed "Mrs. Brisby" in the animated film) actually has no known given name. She is either known as "Mrs. Frisby" or "Mrs. Jonathan Frisby". Most of the animals in the series are Partially Civilized Animals living in a Mouse World.
- In the Dick King-Smith story "A Narrow Squeak", mice Hedley and Ethel have an anniversary coming up. The writer goes on to explain that, because mice's lives are so uncertain, they celebrate anniversaries in days, not years.
- In Tailchaser's Song, cats refer to being in committed relationship similarly to a marriage as a "Joining". Joinings are rare amongst cats as most are noncommittal. Prior to Joining, cats do a special dance called the Dance of Acceptance.
- While marriage isn't used in Warrior Cats, cats do generally mate for life.
- The term, mating, is used in Sekhmet to refer to marriage. They even have a mating ceremony.
- In The Hundred and One Dalmatians, Missis is referred to as Pongo's wife. Perdita once felt "a great desire to marry", although it's pretty clear from context that this is a euphemism for going into heat.
- In the Broad City episode "The Matrix," Ilana's brother Elliot hosts an elaborate wedding for his dog, complete with wedding rings, a yarmulke for the groom, and a gown and veil for the bride. He takes the wedding very seriously and panics every time anything doesn't go according to plan.
- Our Miss Brooks: In the episode "Minerva's Kittens", Mrs. Davis and Miss Brooks wait at the veterinary hospital for Minerva to give birth. They share this exchange:
Miss Brooks: Please, Mrs. Davis, calm down. Even Timothy isn't as jumpy as you are. You're as nervous as a cat.
Mrs. Davis: What is he doing here?
Miss Brooks: Why shouldn't he be here? He's Minerva's husband. It's very nice of him to take such an interest.
- In Faux Pas Randy the domestic fox learned everything he knew about romance from human TV, confusing his wild girlfriend Cindy as to why they needed to be "mare-reed" before having kits.
- The dogs King and Bailey are married, though King is a former human. The vet who helps deliver their puppies is rather sarcastic about this, apparently seeing it as an example of people spoiling their pets, and feeling that Bailey's owner should be more involved than King.
- Wolves Miles and Lucretia are "mated" with three pups but not legally "married." Once Miles remarks that he'd like to "marry my wife someday."
- Sabrina the cat is almost forced to marry an African leopard prince she made a Childhood Marriage Promise to, but her current boyfriend (a dog) derails the ceremony.
- In Our Shadow: The artist has stated that the post-human evolved animals don't really do "marriage," with the one exception seen in the comic being a political marriage between the founder of the Kangaroo Kingdom and the daughter of one of the tribal chiefs he defeated.
- Gravity Falls: In the episode "The Love God", Mabel set up Waddles the pig and Gompers the goat together and has Stan officiate their wedding.
- The Simpsons: In "Fear of Flying", after a Freak Out on an airplane due to a fear of flying, Marge's Sanity Slippage keeps showing up in strange ways, such as carrying Santa's Little Helper and Snowball II into the room and saying:
Marge: I just realized we never had a wedding for the cat and the dog. They've been living in sin.