Bighorn sheep (Ovis canadensis) can catch a bacteria, Mycoplasma ovipneumoniae, from domestic sheep that causes pneumonia in the wild sheep and, often, death. Researchers noted a correlation between the introduction of domestic sheep and the rapid disappearance of bighorn sheep as early as 1928 and pneumonia remains a significant problem for the wild species today.
Are brains over-rated? After all, jellyfish lack them, yet carry out sophisticated functions and a complex reproductive cycle. Their lack of a nervous system control center even confers some advantages, such as the ability to lose a chunk here and there with little harm done.
If you hit the beach recently in the Caribbean or Gulf of Mexico, you may have encountered piles of stinky seaweed. This is what's known as a sargassum bloom.