A high school American football player in the United States had every right to be rattled after finding a venomous snake inside his helmet during practice.

A team was going through its paces at Maumelle High school in Central Arkansas when a student felt unusual movement inside his headgear following warm-ups and brought his helmet to an assistant coach for inspection.

A slithering 2-foot (61cm) cottonmouth was discovered behind some padding.

The pit viper was so reluctant to exit the helmet that police officers had to pour water into it to force the snake out and into a bag.

Animal services technicians arrived a few minutes later, identified the snake as a deadly cottonmouth and took it to a wooded area far from the school.

Cottonmouths are the second-most-venomous snakes found in Arkansas.

Animal services director Chris Davis said the player wore the helmet for nearly an hour and was fortunate he was not bitten.

"It was unreal," Davis said. "You had to kind of be there and take pictures to say this was real."

The player grabbed a different helmet and continued practice.

But the situation caused the head coach to reiterate to his team that players should examine their equipment carefully before using it, to check for insects or anything larger and more dangerous.

AP