Person mildly interested in venomous animals here. There are many animals with weaker venom or even just bacteria who bite, wait out the venom's effectivity and then sniff out their prey. This is one tactic, the animals that develop extremely strong venom have develloped it so the prey dies there and then, rather than allowing it to roam around and die elsewhere, to then get nabbed by another predator. Most animals with venom this string are physically rather weak compared to other predators, and are unable to track down their prey after the bite.
So, as I said, they must kill the prey there and then, so they dont lose it.
Tasha Trix Keyzel
Amber Elizabeth Lewis
Melissa Binder
Saleem Raj
Bhes Raj Baral