Question

And why?

Answer 1

In real life, snakes and mongooses are biological rivals. They're like the stereotypical Dog/Cat fights going on through the ages. Mongooses have also developed antibodies, and are immune to snake venom, which is seen through Zangoose's Dream world ability Toxic Boost, which gives him an advantage of seviper.

Comments

so pokemon and real life are related

---

Drats so close to being first to answer. I guess DT has a more detailed version of my answer XD

---

Lots of the pokemon are based off of things in real life. It's kind of hard to just come up with 600+ pokemon out of the blue.

---

Thats His DW Ability? I think i caught one ingame with it.

Answer 2

I'm guessing it is the pokemon they are based on- Zangoose is a mongoose & seviper is obviously a snake. Mongooses are a snakes natural enemy/predator explaining zangooses immunity & toxic boost abilities that at first sight come out of the blue. I guess that is the cause of the ancestorial rivalry between two of my favourite pokemon.

Hope this helps:)

Comments

so i herd you leik seviper

---

I like hoenn pokemon & snakes