If it's a question of behaviour....
| Ruby | SWAMPERT is very strong. It has enough power to easily drag a boulder weighing more than a ton. This POKéMON also has powerful vision that lets it see even in murky water. |
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| Sapphire | SWAMPERT predicts storms by sensing subtle differences in the sounds of waves and tidal winds with its fins. If a storm is approaching, it piles up boulders to protect itself. |
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FireRed
LeafGreen | Its arms are rock-hard. With one swing, they can batter down its foe. It makes its nest on beautiful beaches. |
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| Emerald | If it senses the approach of a storm and a tidal wave, it protects its seaside nest by piling up boulders. It swims as fast as a jet ski. |
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| Y | It can swim while towing a large ship. It bashes down foes with a swing of its thick arms. |
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Of course, there may be other behaviour exhibited by wild Swampert in the anime &/or manga to consider. For checking that, I'd recommend looking into Bulbapedia's appearances section.
The only notable instance of a Wild Swampert I can find though is this:
https://bulbapedia.bulbagarden.net/wiki/DP109
When a Swampert mistakes Ash & co. for intruders into its territory, it attacks them. Unfortunately, even after looking at the gallery (
https://www.filb.de/anime/dp/109 ) I'm not sure what moves were used by it. So maybe folks can find the episode & check?
But yeah, it seems like Swampert's normal in-character behaviour is using its vision, sensing sounds in waves & tidal winds with its fins to track the weather, protecting itself with boulders, & using its arms to attack.
But that's base Swampert. What about Mega Swa-
It seems like it has no Pokedex entries for its Mega Form, rather atypically.
Reading the Biology Section on Bulbapedia: "According to the
anime, Mega Swampert fills the organs on its back with air before diving underwater or battling; it uses that pressure to increase the power of its punches."
There might be more info on it on the Pokemon OR/AS preview website, but that is a pain to find; I don't remember the url & it may need using the Internet Archive to find it, & even then, I'm unsure if it'll have Mega Swampert info.
But yeah. Mega Swampert's main difference from base in behaviour seems to be that "Mega Swampert fills the organs on its back with air before diving underwater or battling; it uses that pressure to increase the power of its punches."
