Jackalope

 is a rare animal found in Red Dead Redemption as part of the Hunting and Trading Outfits DLC pack.

Characteristics
The Jackalope is a mythical (and in-game, claimed to be legendary) animal of North American folklore (a so-called "fearsome critter") described as a jackrabbit with antelope horns or deer antlers and sometimes a pheasant's tail (and often hind legs). The word Jackalope is a portmanteau of "jackrabbit" and "antalope", an archaic spelling of antelope.

It is possible that the tales of Jackalopes were inspired by sightings of rabbits infected with the Shope papilloma virus, which causes the growth of horn- and antler-like tumors in various places on the rabbit's head and body.

Jackalopes are also brown as compared to the regular grey rabbit in the game (although some rabbits can be found to have tan fur). This makes them easy to spot if around other rabbits.

The player must kill one of these animals in order to unlock the Expert Hunter Outfit.

Upon skinning a Jackalope, a viewable number under Collectibles in the "Stats" section of the menu is shown, implying that more than one Jackalope can be encountered in the game.

Locations
The Jackalope can be found in many locations in the New Austin territory. The following locations have been confirmed:

Cholla Springs locations

 * Just outside of Armadillo and sometimes inside Armadillo, you might see a dog chasing it
 * At Hanging Rock
 * Lake Don Julio
 * In Odd Fellow's Rest between 7:00AM and 3:00PM
 * Around Pleasance House
 * Riley's Charge, in the canyon along the ridge as you're headed north on the road. Mostly they are being chased by foxes and coyotes so be fast!
 * Twin Rocks hideout, near the left stone. Possibly only spawned while clearing it of goons
 * Two Crows, at the house.

Gaptooth Ridge locations

 * Gaptooth Breach, in the center of camps and tents
 * Just south of Rathskeller Fork
 * Just north of Silent Stead

Hennigan's Stead locations

 * MacFarlane's Ranch
 * Around The Old Bacchus Place near Thieves' Landing.
 * Inside Pike's Basin
 * Stillwater Creek, in the south-west corner of the creek, as you're heading back west to MacFarlane's Ranch
 * The New Austin region of Tall Trees, north of MacFarlane's Ranch, above the tip of Pike's Basin
 * Warthington Ranch

Río Bravo locations

 * Around Fort Mercer
 * Under Frontera Bridge, along the shore on the Rio Bravo side
 * Plainview, in the north-west of the timber oil derricks
 * Repentance Rock
 * Río Bravo, just over the Bridge from Perdido. Along the trail adjacent to the canyon wall
 * Rio Del Lobo
 * Solomon's Folly

Trivia

 * The Jackalope looks like a mix of a rabbit and a buck. When skinned, it generates Buck Antlers and Rabbit Meat in your inventory.
 * The Jackalope uses an accelerated version of the rabbits' running animation.
 * The Jackalope is included in the Hunters & Traders Free DLC pack released on October 12th, 2010. There are also new challenges related to hunting the Jackalope.
 * Be careful: The Jackalope does not give off a blue signal like other Legendary creatures. This makes it harder to locate, needing the use of the naked eye.
 * The player can find the Jackalope more than once even though it is a Legendary creature.
 * When encountering the Jackalope unique theme music is played, much like the other legendary creatures.
 * Sometimes (on very rare occasions) a jacklope may run into the Armadillo Saloon (regardless of whether or not the drinking animation is in progress). This sometimes happens because an NPC dog is chasing it or simply by accident.