A data frame with 17 columns: hair, feathers, eggs, milk,
airborne, aquatic, predator, toothed, backbone, breathes, venomous,
fins, legs, tail, domestic, catsize, type.
Most variables are logical and indicate whether the corresponding
animal has the corresponsing characteristic or not. The only 2
exceptions are: legs
takes
values 0, 2, 4, 5, 6, and 8. type
is a grouping of the animals
into 7 groups, see the example section for the detailed list.