10 Unusual Animals That Are Beautiful In Their Weirdness

4. Once this baby echidna grows up, you won't want to hold it in your bare hands. The echidna or spiny anteater, is an unusual mammal. It is so different from any other that it still puzzles researchers and scientists. The echidna has remained unchanged since prehistoric times, finding ways to survive while other species became extinct. But what really sets the echidna apart from other mammals? Female echidnas lay eggs! Egg-laying mammals are called monotremes. There are only five monotremes in the world: four echidna species, and one platypus species.