Species that employ sexual reproduction have two basic schemes to ensure the survival of their genes. Some spread their gametes widely and indiscriminately to produce great numbers of offspring, like plants and many animals. Others produce fewer offspring, but take care of them to boost their chance of survival. Most sea stars use the former technique, but six-rayed sea stars (Leptasterias hexactis) are different. They are different because this sea star looks like a snowflake, with an extra "leg" that other sea stars lack, and it protects its offspring.
Six-rayed sea stars don't have to feed their babies, because they've evolved to carry their nutrients with them, like birds with a yolk. But they grow temporary appendages to hang onto their mother until they are big enough to fend for themselves. On the sea floor, where it's eat or be eaten, this gives them a leg up, so to speak, on other sea creatures. Meet this sea star in a video from PBS's Deep Look series. -via Aeon