To all the squirrels
I've Loved Before. 21 Critters to be found in varied locations. Some of these are in Northrend but this way you can get started ahead of everyone else. Most of the list can be found on the aforementioned page on wowhead, but here's a more complete overview :
# Cat : Eversong Woods, Silvermoon City, Elwynn Forest
# Chicken : Westfall, Hillsbrad Foothills, Elwynn Forest, Arathi Basin, Duskwood, Tirisfal Glades, Shattrath City, The Barrens, Azuremyst Isle, Dustwallow Marsh, Redridge Mountains
# Crab : The Steamvault, Dragonblight, Ghostlands
# Cow : Elwynn Forest, Hillsbrad Foothills, Arathi Highlands, Westfall
# Deer : Elwynn Forest, Darnassus, Teldrassil, Moonglade, Ashenvale, Blade's Edge Mountains, Alterac Mountains, Azuremyst Isle, Darkshore, Stonetalon Mountains, Western Plaguelands, Westfall, Moonglade, Dire maul
# Ewe : Shattrath City
# Frog : Maraudon, The Slave Pens, The Steamvault, Zangarmarsh, Ghostlands, Dire maul
# Fawn : Elwynn Forest
# Gazelle : The Barrens
# Hare : Durotar
# Parrot : Un'Goro Crater
# Prairie Dog : The Barrens, Nagrand, Mulgore, Arathi Highlands, Westfall
# Rabbit : Dun Morogh, Elwynn Forest, Scarlet Monastery, Moonglade, Redridge mountains
# Ram : Loch modan, Wetlands
# Sheep : Elwynn Forest, Redridge Mountains, Loch Modan, Hillsbrad Foothills, Alterac Mountains, Westfall
# Swine : Durotar, The Barrens
# Skunk : Terokkar Forest, Bloodmyst Isle, Azuremyst Isle.
# Squirrel : Darnassus, Ashenvale, Dire Maul, Magisters' Terrace, Zul'Aman, Moonglade
# Toad : Black Temple, The Steamvault, The Underbog, Darnassus, Un'Goro Crater, Wetlands, Swamp of Sorrows, Ghostlands