Animals are new class item similar with the previous three, weapons, armors, and vehicles. This Class item (animals) will released soon.
Right now you can get animals from doing jobs, robbing (Mafia Wars New York Only), fighting and buy with RP.
Here current best animal for attack and defense.

Top 5 OFFENSIVE Animals – All Time

No Animals Attack Attack Animals details
1 Armored War Elephant 96 Mastery Rewards of Commandant
2 African Lion 58 Marketplace:35 RP
3 Sled and Dogs 53 Marketplace:35 RP
4 Vicious Tiger 52 Vicious Crate
5 House Cat 50 Marketplace:30 RP

Top 5 DEFENSIVE Animals – All Time

No Weapon Defense Defense Weapon details
1 Armored War Elephant 69 Mastery Rewards of Commandant
2 Pit Bull 57 Marketplace:35 RP
3 Vicious Cobra 55 Vicious Crate
4 Dublin Stallion 51 St. Patrick’s Day 2010
Marketplace:35 RP
5 Royal White Elephant 48 Marketplace:25 RP
Best Offensive Animals (Lootable) Best Defensive Animals (Lootable)
Spitting Cobra

46 Attack 28 Defense		 Russian Bear

22 Attack 45 Defense
501 * 46 Attack
= 23046 Attack		 501 * 45 Defense
= 22545 Defense

Here list of All Animals avaliable on Mafia Pet Farmville, Mafia Wars. :maho

Name   ? Attack Attack   ? Defense Defense   ?
African Lion 58 36
Anaconda 42 23
Armored War Elephant 96 69
Attack Cobra 24 20
Best Friend 23 40
Blitzen 16 21
Chinese Tiger 26 48
Dublin Stallion 26 51
Forest Scorpion 25 37
Highball 36 24
House Cat 50 37
Howler Monkey 20 37
Hyena on Chain 20 16
Irish Wolfhound 48 29
Jaguar 45 24
Kodiak 44 28
Komodo Dragon 34 22
Kraken 24 41
Laser Squirrel 43 12
Liger 45 12
Pair of Pet Tigers 28 12
Pit Bull 35 57
Rabid Parrot 35 28
Red Boa 19 38
Riding Elephant 18 30
Royal White Elephant 34 48
Russian Bear 22 45
Siberian Tiger 36 14
Sled and Dogs 53 25
Snow Leopard 37 25
Spitting Cobra 46 28
Timber Wolf 41 20
Vicious Anaconda 20 42
Vicious Cobra 30 55
Vicious Hyena 28 29
Vicious Kodiak 41 24
Vicious Parrot 18 31
Vicious Scorpion 34 12
Vicious Tiger 52 34
Vicious Wolf 39 30
Wild Mustang 16 34
Zombie Cow 25 15
Name   ? Attack Attack   ? Defense Defense   ?
African Lion 58 36
Anaconda 42 23
Armored War Elephant 96 69
Attack Cobra 24 20
Best Friend 23 40
Blitzen 16 21
Chinese Tiger 26 48
Dublin Stallion 26 51
Forest Scorpion 25 37
Highball 36 24
House Cat 50 37
Howler Monkey 20 37
Hyena on Chain 20 16
Irish Wolfhound 48 29
Jaguar 45 24
Kodiak 44 28
Komodo Dragon 34 22
Kraken 24 41
Laser Squirrel 43 12
Liger 45 12
Pair of Pet Tigers 28 12
Pit Bull 35 57
Rabid Parrot 35 28
Red Boa 19 38
Riding Elephant 18 30
Royal White Elephant 34 48
Russian Bear 22 45
Siberian Tiger 36 14
Sled and Dogs 53 25
Snow Leopard 37 25
Spitting Cobra 46 28
Timber Wolf 41 20
Vicious Anaconda 20 42
Vicious Cobra 30 55
Vicious Hyena 28 29
Vicious Kodiak 41 24
Vicious Parrot 18 31
Vicious Scorpion 34 12
Vicious Tiger 52 34
Vicious Wolf 39 30
Wild Mustang 16 34
Zombie Cow 25 15