The largest of all marsupials is the red kangaroo (Macrpus rufus).
Camels, lizards, scorpian, centipedes, millipedes, spiders, snakes, goats etc.
Walrus, whale and Dolphins.
The Shrew; a tiny mouse like mammal only two inches long and weighs about as much as a nickel.
Oviparous animal is one which after laying eggs, keeps them within its body to hatch and incubate later.
The study of horses is called Hippology.