A majority of characters in Happy Tree Friends have buckteeth. These are seen most prominently when characters have their mouths closed, though the buckteeth are still visible when they talk, scream, etc. The buckteeth usually cannot be seen when characters grit their teeth or scream with contorted facial expressions. Similarly, when characters grin widely, such the trademark grins of Lifty and Shifty, the buckteeth can become hidden amongst the characters' other teeth.
The buckteeth themself have gone through a transformation as the series progressed. They were originally the general shape of a trapezium with very sharp corners and a flat tip. Later in the TV series, the corners became more rounded, the tips of the teeth are slightly curved, and they have been widened, but the general trapezium shape still remains.
Buckteeth, though common throughout the show, do not appear on all characters. Of the 21 regular characters, Lumpy, Sniffles, Cro-Marmot and Evil Flippy don't have buckteeth. Sniffles' obviously doesn't have buckteeth because of his trunk-like snout and Lumpy simply doesn't have them at all, more often than not, his teeth are halfway up the underside of his nose. Cro-Marmot is stuck in a block of ice, wearing an expression that doesn't show any buckteeth, though he also didn't have them in Dino-Sore Days when he was not encased in ice and this was the animation style was different, such as in "Ka-Pow!", which also didn't show buckteeth on Flippy (see below). Another point about Flippy is he usually has buckteeth in the normal series, however, when he flips-out, his teeth becomes crooked in the internet shorts (this is still used fairly often with other Happy Tree Friends when they are scared), and in the TV series and further on, they become sharp.
Due to his turtleneck, The Mole's mouth is not visible (but he is proven to have buckteeth as shown in Pet Peeve). The Demon has red sharp teeth on the beak. Sneaky has no teeth. Truffles, Char Sui and Pig Child are pigs and don't have buckteeth.
Sometimes when characters scream, their teeth become crooked, with one tooth on the upper side and one on the lower side of their mouth. The Generic Tree Friends are occasionally seen to have buckteeth, very few other characters (anthropomorphic or not) have them. None of the characters in Three Courses of Death or Mole in the City have buckteeth, though the Generic Tree Ninjas may have buckteeth beneath their masks, one skeleton was seen when Buddhist Monkey disintegrated one internally, and it shows teeth that aren't buckteeth, however, they are simply just a series of white blocks, so this may not be their official teeth. In Operation: Tiger Bomb the only character to have buckteeth was Mouse Ka-Boom, which is odd considering that Flippy has buckteeth in the normal series. This could indicate that the animation of the Ka-Pow simply doesn't utilize the bucktooth drawing format and that characters from Ka-pow would have buckteeth if they were animated in a typical Happy Tree Friends way, this is supported by the body design of Flippy being vastly different from normal Happy Tree Friends animation as well. However, assuming this is a animation style that does not typically show buckteeth, Mouse Ka-Boom may have them because he is a mouse, which generally have large front teeth.
Toothy has buckteeth that are larger than those of the other characters, with a huge gap between them that some attribute to diastema. Toothy's name is derived from his larger than normal buckteeth, though there have been instances where his buckteeth were normal. In some episodes, like Treasure These Idol Moments and Class Act, Toothy's buckteeth change back and forth between normal and large and gapped several times. In other episodes, such as Eye Candy, Toothy has normal buckteeth throughout the duration of the episode. This problem was said to be caused by laziness on the part of the animators, though this was fixed when Fatkat took over the animation for the television series.
The heart-shaped noses are clearly based on the similar facial concept of the Care Bears and the Care Bear Cousins. Lumpy and Sniffles are the only main characters who don't have them. Most of the characters have pink heart shaped noses, but Flaky's nose is dark red and Disco Bear's nose is burnt orange. The Tiger General and his soldiers have blue noses, however, these noses are closer to a "v" shape than a heart. Sneaky from W.A.R. Journal doesn't have a visible nose because of his reptilian design. Truffles, being a pig, has a pig snout.
A character's skull also has a heart-shaped hole where the nose would be. It used to be an upside-down heart but it was changed to right-side up. Lumpy has his two nostril holes on his skull, and a generic tree ninja was shown to have two half-triangles, not completely dissimilar from a human skull.
Sniffles has a trunk-like snout instead of a typical nose. However, his snout was originally longer before being shortened at the tail end of Season 2. It would later change again from being curved to straighter and slightly more shortened.
Pac-Man EyesMost of the characters have eyes with pupils the shape of an ovular Pac-Man. Evil Flippy, Lifty, Shifty, Lumpy and Nutty are the only main characters who don't have Pac-Man eyes (though Lifty and Shifty had Pac-Man eyes in early episodes). It is unknown whether Cro-Marmot and The Mole have the same eyes as the others, as The Mole wears typical shaded glasses and Cro-Marmot's fringe is covering his eyes. Cub and Mr. Pickels have small black dotted eyes (which still form the Pac-Man shape). The Rat and The Dark Shadow Lord don't have Pac-Man eyes. When Flippy flips out, his eyes go from Pac-Man to irises and his pupils are completely round. Similarly, Pupils often dilate or constrict depending on a character's mood
Sometimes, when a character suffers from injuries, death or panicked. The eyelid or the area next to the eye may become little darkened (example Cuddles in episode Water You Wading For or Petunia in Hello Dolly.), but otherwise have small stripes below character's eye.
Notable exceptions to Pac-Man eyes/pupils are:
- Lumpy: Googly eyes
- Nutty: One googly eye, one flippy-like eye
- Flippy: Yellow/green eyes, or once blue, when flipped out
- The Dark Shadow Lord: Glowing, red eyes
- The Rat: Red pupil and iris.
- Lifty & Shifty: Beady pupils.
Mitten hands are hands that are mitten shaped in appearance (a thumb, and, where the fingers would be, is, essentially, an extension of one's hand). Lumpy, Handy, Lammy, and Mr. Pickels are the only main characters not to have mitten hands. Russell has one mitten hand because he has a hook on the other. It is certainly unknown whether Handy has mittenlike hands or not before they were amputated but it is likely they were. Petunia has mittenlike hands and got them amputated in I Nub You. Characters' mitten hands often change to hands with fingers whenever characters grip something, gesture at something, experience extreme pain, etc. Though Flippy and Splendid had mitten hands in Happy Tree Friends, they don't in the Ka-Pow! series.
Split Lips and Triangular Frowns
The Characters have a line connecting their nose to their mouths. When a character frowns, the frown is the shape of a triangle or a carrot sign (^), with one half going off from that line. The only characters who cannot make this frown are Lumpy, Sniffles, and Mr. Pickels. It is possible, but unknown, if The Mole and Cro-Marmot can make a triangle-shaped frown, as the former has the top of his turtleneck covering his mouth while the latter is frozen.
Most characters, have round ears at a certain angle on their head, roughly at right angles or 100 degrees from each other. The Mole has ears on top of his head instead of the sides. Lumpy, Russell, Flaky and Handy (except for two episodes) have no ears. Sniffles, Mime, Lifty, and Shifty have pointed ears and Cuddles has very long ears. In some cases, the characters have ear-holes that are another shade of their fur color.
Most characters wear shirts, pants, hats, footwear, or some form of apparel. Cuddles wears pink bunny slippers. Giggles wears a red bow on her head. Petunia wears a flower on her head and an air freshener as a necklace. Handy wears a hardhat and a belt. Sniffles wears large glasses and a pocket protector. Nutty wears candy as clothing (as seen in Chew Said a Mouthful). Russell wears pirate-like clothing. Disco Bear wears a 1970's style disco suit. Mime wears a striped shirt. The Mole wears sunglasses and a purple turtleneck. Shifty wears a fedora. Pop wears a red bathrobe and hat. Cub wears a beanie hat and a diaper. Cro-Marmot usually wears a loincloth. Splendid wears a red mask. Flippy wears soldier-like clothing and dog tags. Lammy wears a wool sweater. Mr. Pickles wears a top hat. Truffles wears a sailor suit. Many secondary characters also wear clothing or apparel. Toothy, Flaky and Lifty are the only main characters who do not wear any form of apparel.
Some characters seem to wear clothes which are not visible because they are the same color as their skin/fur, mos notably Lumpy. He appears shirtless in You're Bakin' Me Crazy and Let It Slide, as shown by his tan line and nipples. In the former, he is seen ironing his blue shirt. Also in I've Got You Under My Skin, he is shown taking things out of his pockets, indicating he wears pants. Cuddles is also shown to have pockets in In a Jam, as with Lifty and Shifty in Sea What I Found and Nutty in Icy You. It is possible that Sniffles could be wearing a shirt due to his pocket protector.
Most of all the HTF characters have an oval-shaped abdominal marking that is lighter than the character's real color. The only characters who do not have an oval marking are Lumpy, Sniffles, Cub, Disco Bear, Russell and Cro-Marmot. It is unknown if The Mole, Pop, Lammy, Truffles and Mime have one due to fact they wear shirts concealing the majority of each of their torsos (although Pop is not likely to have one because Cub doesn't.). Splendid's abdominal marking used to be straight at the bottom in the internet series, but it became curved in the TV series.
Face markings are different shaped markings on certain HTF characters' faces. The only seven characters who have a face marking are Tiger Soldiers, Cuddles, Giggles, Petunia, Nutty, Mime, Lifty, and Shifty. Cuddles and Mime have Rosy-red cheeks (although, Mime could be wearing makeup). Giggles and Nutty both have diamond shaped markings on their foreheads, while Petunia has an arrow shaped marking on her forehead which is connected to a triangle shaped marking on the back of her head. In all three cases, the color of these markings are lighter than the fur on the rest of their bodies. Lifty and Shifty, on the other hand, have darker mask-shaped markings around their eyes, to go along with the theme of their kleptomania (urge to steal). Tiger Solders have a sky blue giant vertical line marking on the between the eyes.
While many characters have fur, some also have hair on their heads. Disco Bear is the most notable example, having an afro of orange hair on his scalp. Cub also grows hair in Snip Snip Hooray!. Cuddles and Lammy have cotton-like hairs at the top of their heads which are identical to their cotton-like tails. Flaky has spiky hair with dandruff. Truffles has a curly hair on top of his head.
Facial hair is also common in some characters. Lifty, Shifty, Truffles, FatKat, Tiger General and the Tiger Soldiers have whisker-like tufts of hair growing from their cheeks. Russell has whiskers, though he also used to have a facial stubble in early episodes. Mr. Pickels has a curly mustache. Lumpy has a mustache and beard in Double Whammy part 1 and just a mustache in Pitchin' Impossible.
21 Characters have feet shaped like a boot. Russell, Char Sui, Truffles, Mr. Pickels, and the Ants all have no boot-shaped feet. Russell has two peg legs instead of boot-shaped feet, though it is unknown but very likely that he had boot-shaped feet like the others before he lost them.
Some Happy Tree Friends have tails, some have none and all different.
- Panda Mom, Giggles' Mom, The Demon, Giggles, Pop, Cub, Flaky, The Mole, Cro-Marmot, Disco Bear, Lumpy and Flippy have no tails.
- Russell has a slightly smaller, furry flat tail.
- Buddhist Monkey has a long monkey tail.
- Petunia, Nutty, Lifty, Shifty, and Splendid all have large bushy tails (the early version of Giggles also have tail of this type).
- Mime has a small tail which disappeared in the TV series, but returned in mid Internet Season 3.
- The Ants have abdomens.
- Whistle has a dog tail.
Generic Body Shape
Most characters in HTF have a similar body shape (small plump body, with a large oval head). Lumpy is much taller and skinnier than the other characters and has a smaller, narrower, elongated head. Giggles' Mom is also taller, but she is less lanky than Lumpy and has an oval head. In Ka-Pow!, this is changed, and everyone is more unique.