Being an animal lover I do have a weakness for creature based apps, both realistic and fantasy. Ultimate Sharks is great for anyone interested in these sleek killing machines of the deep and the graphics and interactive features are very engaging. If you have a copy of Guinness World of Records 2013 using the app that goes with it makes a shark almost leap out of your ipad at you - first time it happens I'm sure it will make you jump! There is also a far too realistic (for me) tarantula that will run over your screen.....if you really want it to.
When my children were small I bought them the book Animalia which is a finding book in the same vein as Where's Wally but with beautifully detailed illustrations of animals by Graeme Base. The app has been very carefully thought out and features readings by the artist, games and animal sounds.
Games are not my strong point and I don't have that many that I play regularly but I must admit when I was introduced to Kinectimals (app of the popular XBox game) by my daughter I was charmed and spent a fair bit of time teaching my big cat cubs tricks, feeding them and keeping them exercised. My favourite is naturally the tiger cub but they are all extremely cute.