What kind of snakes or spiders your dog might encounter depends on where you live.
Some of the most dangerous species of snakes include rattlesnakes, copperheads, and water moccasins. The outcome depends on the amount of venom injected, location, size of the dog … but I would treat any and all of these as an emergency because the sooner your dog gets help the better.
Prompt and aggressive treatment can save your dog’s life.
I would like to note that even a bite from a non-venomous snake can become devastating because of the potential for serious infections.
The signs that should make you suspect a snake bite even if you didn’t see what happened include sudden yelp, intense pain, and rapid swelling. You may or may not be able to find puncture marks. The wound might bleed, and your dog might show signs such as drooling, rapid breathing, dilated pupils, pale gums, weakness, vomiting, neurological signs …
I can’t imagine even considering not to rush to a vet if I knew or suspected my dog was bitten by a snake.
Spider bites are generally much less scary and can even slip under the radar. But how dangerous a spider bite might be depends on what spider did the deed. Most spider bites might cause some itching and irritation, and that’s about it.
Some can cause swelling and major infection. And some can be extremely dangerous, particularly for smaller dogs.
Know what species might be crawling in your area.
The most dangerous spiders are the black widow and brown recluse.
Most spider bites don’t require medical attention. But if your dog acts sick or develops a lesion at the bite site, it’s time to call your veterinarian.