I was reading about the mosasaurs, and there seems to be some debate on whether they were most closely related to Komodo dragons or to snakes. So I started wondering whether the mosasaurs could have had some sort of toxic bite.
They were pretty big, so I can’t see that venom would have helped them much in hunting. But there were lots of other big things around, too, so they may have used it for defense.
Do we know (or suspect) anything about that, like did some of the larger marine reptiles from that time have hollow fangs or grooved teeth or anything else that might suggest that they were venomous?
Are there any large animals (then or now) that are venomous? It seems to me the biggest they get is the stingray or jellyfish (which are not too mobile). AFAIK these tend to be more defensive, not for hunting.
I have always wondered why more mammals did not evolve venom. The platypus and the echidna are the only two that I know of and they use it purely for defense. It might create a mammal that is too successful and quickly wipes out his food source.
Mosasaurs are part of the assumed clade Toxicofera, which has venom as a feature. So, it’s quite possible they did have venom, but unlikely to have the advanced toxins and delivery systems that some snakes have.
And mammals by courtesy and definition. They are also the only two egg-laying mammals.
Research suggests that the echidna evolved from an animal with toxic spurs, but the spurs aren’t poisonous now. On modern echidnas, it’s used for marking, like what a cat or dog does. On modern platypuses, the gene is called a ‘defensin’ gene, for ‘defense’ against microbial infection, but the spur is apparently mainly used for mating competition.
At least I feel a little better about dispatching the rat snake that slithered into my garage, not only refusing to leave when encouraged to do so, but rearing and lunging at me as well.