Worms, fleas, ticks and other parasites
some animals develop wings. others get it from traits. such as genetic traits.others well i dont know about that
Because some don't have the ability. That's true for individuals, As a species, all multi-celluar animals must mate or else become extinct.
Well the Dog,Cat,Snake even though it may be a reptile I have on to pet,and also a Horse,Cow,Chicken,Bird and many many more :)
polar bear, black-footed ferret,