| 1 | Red, Blue | Moves silently and stealthily. Eats the eggs of birds, such as Pidgey and Spearow, whole. |
| 1 | Yellow | The older it gets, the longer it grows. At night, it wraps its long body around tree branches to rest. |
| 1 | Stadium | Slithers silently through grass, searching for its favorite food—Pidgey and Spearow eggs. |
| 2 | Gold | It can freely detach its jaw to swallow large prey whole. It can become too heavy to move, however. |
| 2 | Silver | It always hides in grass. When first born, it has no poison, so its bite is painful, but harmless. |
| 2 | Crystal | It flutters the tip of its tongue to seek out the scent of prey, then swallows the prey whole. |
| 2 | Stadium 2 | It can freely detach its jaw to swallow large prey whole. It can become too heavy to move, however. |
| 3 | Ruby, Sapphire | Ekans curls itself up in a spiral while it rests. Assuming this position allows it to quickly respond to a threat from any direction with a glare from its upraised head. |
| 3 | Emerald | An Ekans curls itself up in a spiral while it rests. This position allows it to quickly respond to an enemy from any direction with a threat from its upraised head. |
| 3 | FireRed | A very common sight in grassland, etc. It flicks its tongue in and out to sense danger in its surroundings. |
| 3 | LeafGreen | Moving silently and stealthily, it eats the eggs of birds, such as Pidgey and Spearow, whole. |
| 4 | Diamond, Pearl, Platinum | It sneaks through grass without making a sound and strikes unsuspecting prey from behind. |
| 4 | HeartGold | It can freely detach its jaw to swallow large prey whole. It can become too heavy to move, however. |
| 4 | SoulSilver | It always hides in grass. When first born, it has no poison, so its bite is painful, but harmless. |
| 5 | Black, White, Black 2, White 2 | It sneaks through grass without making a sound and strikes unsuspecting prey from behind. |
| 6 | X | The older it gets, the longer it grows. At night, it wraps its long body around tree branches to rest. |
| 6 | Y | Moving silently and stealthily, it eats the eggs of birds, such as Pidgey and Spearow, whole. |
| 6 | Omega Ruby, Alpha Sapphire | Ekans curls itself up in a spiral while it rests. Assuming this position allows it to quickly respond to a threat from any direction with a glare from its upraised head. |
| 7 | Ultra Sun | By dislocating its jaw, it can swallow prey larger than itself. After a meal, it curls up and rests. |
| 7 | Ultra Moon | The eggs of bird Pokémon are its favorite food. It swallows eggs whole, so sometimes an egg gets stuck, and Ekans faints. |
| 7 | Let's Go, Pikachu!, Let's Go, Eevee! | The older it gets, the longer it grows. At night, it wraps its long body around tree branches to rest. |
