Soft tissues generally do not show up well in fossils. That missing information means that paleontology is particularly fertile ground for speculation. One of my favorite bits of paleontological speculation comes from Putting the Life Back in Science Fiction where a post wonders whether plesiosaurs had long necks to allow for electric organs like electric eels, useful for defense, electrolocation, and fishing. The post is careful to note that it is indulging in wild speculation.
The speculative theory probably isn’t true, but it is more fun to imagine that it is.