Shou Dou Qi is an old Chinese game for two players. One finds this game under many different names, most common: The Jungle Game, or just Jungle. One can find descriptions of this game in several game books.
One can debate whether one can call this game a chess variant - it probably is not, although it sometimes is regarded as such.
The game is played on a board of nine rows and seven columns. The board has several special areas: each player has at his side of the board a Den, which is surrounded by three Traps. In the middle of the board there are two Lakes.
Each player has eight pieces: an Elephant, a Lion, a Tiger, a Leopard (here depicted by J for Jaguar), a Dog, a Wolf, a Cat, and a Mouse (also called: Rat).
Each piece moves one square horizontally or vertically (not diagonally). The mouse is the only animal that is allowed to go to a water square; none of the other animals may move to a water square.
The lion and the tiger may jump over the water, when going in a horizontal and vertical straight line. (They jump to a square at the border of a lake to another square at the border of the same lake. For instance, a lion at a4 can only jump to d4.) When jumping, there may not be a mouse on one of the squares that is crossed; there may be a mouse on the square that is landed on.
Pieces have a strength: stronger pieces take weaker pieces. The elephant can take all other pieces, the lion all other pieces except the elephant, the tiger is the third strongest piece, i.e., wins from all pieces except lion and elephant, then come in order the jaguar/leopard, dog, wolf, cat, and mouse. There is one exception: a mouse can take an elephant. However, the elephant can also take a mouse, i.e., the moving player wins the battle between elephant and mouse. One takes a piece by moving a stronger piece (or a piece of equal strength) via a legal move to the square containing that piece. When jumping, lions and tigers can take pieces that are on the square they land on. Mice may not take elephants from outside a water square. A piece can take a piece of equal strength: when two pieces are of equal strength, then the piece that moves takes the other piece.
A piece of a player in one of his own trap squares cannot be taken by the opponent. Pieces in a trap square of the opponent are very weak: they can be taken by any other piece when in such a trap square.
As observed by Jeff Mallett, this rule makes it much easier to obtain a draw: one should just have fill each of ones traps by a piece and the opponent can never reach the den (except by Zugzwang). One can play instead e.g.: any piece in a trap square is weaker than any other piece. Or just treat trap squares as ordinary squares, as is done in a book by R. C. Bell.) However, read the comment of Ralf "Panther" Gering.
A player may not move a piece to his own den. A player wins the game by moving a piece to the den of the opponent.
Also, in one of the software programs for Jungle, the Wolf is ranked above the Dog; this difference is not important, as it is unlikely that they meet, as they are defensive pieces.