The animal kingdom features a surprising array of swimmers. Even land-dwelling animals can thrive in aquatic environments when necessary.

They're pulled from backyard pools and bathtubs each year, tiny limp bodies, blue and not breathing. A young life can vanish quickly under water. A survivor can endure a lifetime of disabilities.

The three-year-old girl, named only as Matilda, was on holiday with her family in the seaside resort village of Lardos on the ...