Rattlesnake vs. Top North American Predators

Factual Questions
1

I know that rattlesnakes can kill humans, but what effect do they have on North America’s top predators? Let’s say that a full-size Eastern Diamondback rattlesnake has just gotten in a good strike against a big ol’ alligator (it found a vulnerable spot and didn’t just glance off the armor) and has unloaded a megadose of its venom. Does the gator die? Or can it shrug the venom off? Would it be a quick death or a prolonged struggle, during which time the alligator crushes and consumes its venomous opponent, only to expire afterwards?

Same deal with an adult cougar, wolf, and black bear. What happens if these animals get bitten by a big rattler?

Thanks for any information that you can give me, and no, I don’t need the answer fast.

2

Rattlesnake bites are rarely fatal to adult humans, so it’s unlikely to be worse for larger animals.

3

I don’t have a factual answer to all of the animals listed but my guess would be unless the snake hit an artery it wouldn’t be enough to kill them. Though very young and very old people do die occasionally, rattlesnake bites aren’t that deadly to humans.

4

A rattlesnake bite might not kill a buffalo directly, but it must have some effect leaving the creature more vulnerable to other predators.

5

Looking at the Wikipedea page on the Eastern Diamondback one gets some useful numbers to at least put it in context.

The top end venom delivery is about 1000mg, and the best possible LD[sub]50[/sub] is an intravenous hit that gets you about 1.4mg/kg toxicity. So, the absolute best, would mean that a big rattler has a 50% chance of killing an animal of about 700kg. Which is still remarkably impressive. However, the other end of the scale, an average venom dose delivery sub-cutaneously is only 1/20 as effective. Meaning a 35kg animal has a 50% chance. In reality, an IV delivery of venom is extraordinarily unlikely. This is why you see low human mortality rates.

Looking at the diet of the rattler, and the makeup of the venom, one sees that on the whole, it isn’t a super dangerous beast. The most important point is that the prime purpose of the venom isn’t to kill the prey, it is to help digest it. The rattler venom does contain a neuromuscular toxin, that probably is the main cause of death of the prey. Although there are other good reasons why the rest of the venom will kill. One notes that the toxin is highly painful. The mode of hunting is that the rattler strikes the prey, and then lets it go, and then follows the now dying animal. So death is slow and painful, and then you get eaten.

So, if a rattler struck a bear, the chances are that the bear would survive, and the rattler might get eaten. That pretty much goes for all the other animals too. Although as they get smaller, they have a higher chance of dying.

Striking an alligator would be interesting. The rattler venom has evolved towards mammals, and it might be that the cocktail of toxins is somewhat less effective on an alligator, although the basic digestive ones probably work fine.

Long term, even a very large animal is going to have problems at the bite site, as the nectrotising effects of the venom may lead to significant internal injury, or even gangrene. That isn’t go to help survival. In humans this remains a real issue for snakebite. You can survive the bite, but the long term damage to the bite area can take a lot of managing.