a young water moccasin

• -2264, -157, -18 (2 of 3 spawns here)
• -2054, -243, -12
• -2250, -617, -20 (seen once) (2 of 3 spawns here)
• -1230, 309, -32 (seen once)
• -1810, -115, -23 (seen once)
• -1818, -265, -25 (seen once) (1 of 2 spawns here)
• -2067, -322, -10 (seen once) (1 of 3 spawns here)
• -2111, -219, -15 (seen once)
• -2242, -97, -21 (seen once) (1 of 2 spawns here)
• -2428, -478, -33 (seen once) (1 of 2 spawns here)
• -2557, -544, -33 (seen once)
• 1124, 1335, -32 (seen once)
• -871, 1255, -23 (seen once)
• -938, 188, -18 (seen once)
• -2056, 203, -32 (seen once) (1 of 3 spawns here)
• -1998, -144, -32 (seen once)
• -1851, -592, -39 (seen once) (1 of 2 spawns here)
• -1995, -260, -6 (seen once)
• -2086, 43, -33 (seen once)
• -2147, 22, -32 (seen once)
• -2207, 250, -21 (seen once)
• -2267, 142, -32 (seen once) (1 of 2 spawns here)
• -2265, 23, -33 (seen once)
• -2349, 77, -28 (seen once) (1 of 2 spawns here)
• -2222, -446, -32 (seen once) (1 of 4 spawns here)
• -2448, -561, -34 (seen once)
• -320, -57, -30 (seen once)
• 1690, 1530, -22 (seen once)
• 1366, -164, -29 (seen once) (1 of 2 spawns here)
• -777, 1509, -31 (seen once) (1 of 3 spawns here)

As /loc gives them: Y, X, Z, the most used first; nearby spawns share a spot, and one seen in a single visit may be where the mob had been pulled to.