Video: Couple find Mexican black kingsnake in garden drain Amateur video shows the moment Linda Peck and her husband Geoff spotted the Mexican Black Kingsnake poking its head out of the grate at their home in Cleethorpes, Lincolnshire. The couple first thought it was 'a black slug' before the reptile slithered from the drain, showing that it was in fact two feet long. The constrictor snake has no venom and lives off a diet of mice. It was guided into a recycling box by the couple's firefighter son Simon, 37, who then handed it over to the owner of a nearby reptile shop. Reptile experts believe the snake had been living in the sewers around Cleethorpes and Grimsby. The large Mexican king snake, a species common in the wilds of Mexico and Arizona, can grow up to 4ft in length and can live up to 15 years.