Shifty and his brother Lifty are two green kleptomaniac raccoon identical twin brothers with dark green mask-like markings around their eyes. They frequently steal merchandise and produce from the other Happy Tree Friends (thus their names), as well as treasure hunting, ransacking houses or anything to get rich quick with the exception of Flaky, Lammy, Cro-Marmot and Splendid. They mostly steal from Lumpy (in Meat Me for Lunch they stole meat from Lumpy's deli mart, in Milkin' It they stole a cow from Lumpy's farm, in Concrete Solution they stole his wallet, and in Junk in the Trunk they abducted his pet elephant). They probably rob Lumpy so frequently because his lack of intelligence and common sense makes him an easy target.
Although they have the same gender, appearance, and personality, Shifty wears a fedora and often bosses Lifty around. It is known that Shifty is the older brother of the duo, since he is a little taller and has a slightly lower-pitched voice. Despite the smirks on their faces, they almost always end up dying in the episodes in which they appear. Their green color implies money and greed relating to their criminal personalities. They also have a trademark evil snicker (usually a different one for later episodes). Like most siblings, Shifty argues to his brother about who's at fault it is when something goes wrong, but when trouble is afoot, they work together. Shifty has been known to betray Lifty at some points, as seen in Milkin' It when Shifty threw Lifty out of a hot air balloon as not to get caught by a cable. Also, in Sea What I Found Shifty had a chance to save Lifty, but instead just stole the jewels. In Easy For You to Sleigh, he abandons Lifty when he gets caught in a trap.
Despite their numerous illegal activities, they often contribute to recreational activities (such as going on a roller coaster and participating in a Christmas play) without causing any trouble. On rare occasions they earn cash honestly and have even been heroic, such as in Happy Trails Pt. 2: Jumping the Shark, when they provided a life raft to help the characters escape from an island.
Lifty & Shifty occasionally make money by themselves without stealing, like when they sold dogs who go crazy when they hear a whistle in Doggone It and when they sold bottles of hair growth formula to Disco Bear in Easy Comb, Easy Go. They also trade or sell things to Nutty, such as in Dunce Upon a Time and the Happy Tree Friends: False Alarm episode (although it could be that these were stolen previous to the episode). They also sometimes show brotherly love towards each other in some episodes, including The Wrong Side of the Tracks, in which they were seen paired up together while riding on Lumpy's theme park roller coaster, Sea What I Found, in which they were seen playing chess together while waiting underwater, As You Wish, in which they were seen hugging each other happily when having their wishes granted leading to their deaths, and Gems the Breaks, in which they were seen glancing at each other lovingly while testing the kryptonut on Splendid.
At the table in Kringle Feast, one of the green legs belongs to Lifty and the other to Shifty.
In Shifty's MySpace Profile, it explains in Shifty's marital status that he is currently in a relationship. The page also states that he and Lifty are both 28 years old, though this is probably just a throwaway gag.
Lifty seems to be the mechanic of the duo, as in a few episodes he is seen working on their van or vehicle. Shifty, on the other hand, drives their van in a majority of the episodes.
Despite being one of the least appearing of the 20 major Happy Tree Friends main characters, they had four starring roles in the TV series, the third most behind Lumpy and Sniffles.
They appeared in 13 out of the first 18 TV episodes but only in 4 of the last 19.
Unlike Pop and Cub, they have never been seen without each other (the only exception being spaced out deaths and Easy For You to Sleigh).
There has never been an episode where one of them has died while the other survives. They always either die or survive together (although sometimes they suffer different deaths, and for the first time inCheesy Does It, both survive while Shifty is injured and Lifty is unharmed).
In early episodes their pupils are normal like any other Tree Friend (like Pac-man pupils). However occasionally in early episodes, and always in later episodes, their pupils dialate/shrink making them appear more mischievous.
Lifty and Shifty say "Uh-oh!" when something goes wrong.
While they rarely appear in the internet series, they appear in a majority of the TV episodes.
They appear in all three episodes of "The Third Degree" and "One Foot in the Grave".
They don't always die the same deaths, and they don't always die at the same time. Junk in the Trunk featured the only instance where they did not die at the same time or one right after the other, while Cheesy Does. It marks the only episode where both survive but one of them gets injured (in this case Shifty gets injured while Lifty is left unharmed).
Although they are identical twins, Lifty's voice is slightly higher pitched than Shifty's voice.
They are voiced by Kenn Navarro, the same voice actor who does Cuddles and Good Flippy, although Lifty and Shifty sound nothing like Cuddles and Good Flippy.
Lifty and Shifty are two of five green characters, the other four are Nutty, Cro-Marmot and Flippy. They both were made green possibly to match the color of money.
Shifty's most frequent victim is his twin brother Lifty.
In the episode Class Act, Shifty was seen dragging Lifty, so it is evident that even though Shifty killed Lifty once (Milkin' It) and left him to die (Sea What I Found), he still tried to save his brother; however, at the time, there was no danger to Shifty, so it is fair to assume he cares for his brother, but at any sign of danger, he'll leave him behind.
Because of a goof in the opening credits of As You Wish, Lifty and Shifty are two of three characters to have only just their names and not along with "starring" and "and" in the first season of the TV Series, the other being Mole.
Lifty & Shifty are the only characters who have triangle-shaped ears.
Their laugh is unique to other HTFs. Most other HTFs either giggle or laugh.