Human

The term human is used in the TV show, despite all of the characters appearing as anthropomorphic animals. Instances include:

Albums

 * Poetry Club (track): Buster: "Finding a human bone in your jello"

Books

 * Mrs. Tibble in Arthur's Halloween and she and the Tibble twins in both Arthur Babysits and D.W.'s Guide to Preschool, although all 3 become bears in the cartoon

Season 1

 * Arthur and the Real Mr. Ratburn: Buster: "Get with it, Arthur. We're not dealing with a human being here. This is serious!"

Season 5

 * The Last of Mary Moo Cow: "only one person stands between crime and humanity"
 * You Are Arthur: in the introduction "Human treasure, lad, not buried treasure"

Season 6

 * Arthur Loses His Marbles: Buster: "Oh, the humanity!,"

Season 13

 * Paradise Lost: when Kate begins to lose her comprehension of Pal's speech, Amigo explains "This happens to all human children. I remember when it happened to Vicita."

Season 17

 * Dog's Best Friend: Pal asks, "Who knows why humans do anything?"

Season 19

 * Brain's Brain: Arthur says, "I wonder how many neurons there are in a human brain."

Season 20
Ladonna is called a “bunny whisperer,” although there is no lampshading of the fact that she is a bunny herself.
 * 2001b. "Arthur and the Whole Truth"
 * Buster responds to Arthur's shirt by saying: “Please, for the love of humanity, hide that thing!”
 * 2002a. Fern's Flights of Fancy"
 * Fern imagines writing a book called Portrait of the Aardvark as a Young Man.
 * The characters in Fern's story are portrayed as humans.
 * 2002b. "Cereal"
 * Buster refers to Arthur as “an average eight-year-old aardvark.”
 * 2003a. "He Said, He Said"
 * Buster refers to a “man-eating plant.”
 * The Breeze in the Brambles characters look more like real-world animals (tails, claws), except for their clothes. The mouse does not seem to be able to speak human language.
 * 2003b. "Bunny Trouble"
 * 2004a. "Bud's Knotty Problem"
 * D.W. tells Bud to make "bunny ears" when teaching him to tie his shoes.
 * 2005a. "Lend Me Your Ear"
 * Mr. Ratburn's ear model is of a human ear.
 * On Mr. Ratburn's imaginary ear tour, he and the boys are seen climbing into a human ear.


 * 2005b. "The Butler Did It"
 * Mr. Crosswire repeatedly treats the robot butler KEATS like a dog. His butler Bailey is an anthropomorphic dog.

Season 21

 * 2101b. "Brain and the Time Capsule"
 * The stars of Keeping Up with the Kamerahounds are anthropomorphic dogs.
 * 2103b. "Sue Ellen & the Last Page"===
 * Buster compares the citizens of Elwood City to “a bunch of hairy animals glued to their cell phones.”
 * Muffy suggests to Sue Ellen to do a video about saving kittens.
 * 2105b. "Take a Hike, Molly"
 * Slink jokingly refers to Molly as a “very grumpy, dangerous animal.”
 * 2107a. "Invasion of the Soccer Fans"
 * The dogs repeatedly refer to the anthropomorphic characters as “people.”

Season 22

 * 2201b. "The Feud"
 * Arthur plays Dr. Aardvarkian in a video game. Later in a fantasy, Arthur voices Dr. Aardvarkian while Buster voices Dark Bunny.
 * 2202b. "The Longest Eleven Minutes"
 * When Arthur opens a dictionary, the first thing he sees is a picture of an aardvark.
 * 2203b. "Binky Can't Always Get What He Wants"
 * Buster does a magic show in which he pulls a nonanthropomorphic white rabbit out of a hat.
 * 2204a. "Muffy's Car Campaign"===
 * Mr. Crosswire is allergic to dogs, despite his trusted butler being one.

Season 23

 * 2303. "When Duty Calls"
 * When Ladonna claims that she has never been better, nonanthropomorphic General Higgins puts his paws on his hips and looks reproachfully. For the rest of the episode, he behaves like a normal rat.

Season 24

 * 2403b "Freaky Tuesday"
 * After turning into Mr. Ratburn, Buster is shocked that his hands are covered with hair.

Season 25

 * 2502a. "Making Conversation"
 * George tells Arthur, Francine, and Buster that people pinched his antlers at the house party, and they all pinch his antlers too. A random partygoer later pinches his antlers too at Mrs. Renaldi's retirement party.

Special 1 - "Arthur's Perfect Christmas"

 * George wears Christmas tree ornaments on his antlers.

Special 3 - "D.W. and the Beastly Birthday"

 * Buster says about a drawing of anthropomorphic llamas, “They all look like mutants to me.” When asked what sort of creatures they are, Arthur answers, “maybe an aardvark.”
 * Kate refers to Buster as “that dopey kid with long ears.”
 * Buster says that he would not fit in a wormhole, but “maybe a rabbit hole.”

Special 4 - "Arthur and the Haunted Tree House"

 * Bailey claims that cats "believe [he's] one of them". Inky reacts to him as he might react to a dog.
 * An anthropomorphic cat at the Halloween party is dressed like Catwoman.
 * Despite being a goat himself, Mr. Saperstein’s golem costume has rabbit ears.