Slipping away: coaches and personnel men are dismayed that one of the game's essentials--tackling--has declined steadily, if it has not become a lost art. (NFL).

When the Ravens' defensive players convened in May for their first meeting at minicamp, they viewed a 6-minute video that looked like a collaboration of NFL Films and Wild Kingdom. They saw a quartet of Chicago Bears converge on former running back James Brooks. They watched Ray Lewis tackle Browns receiver Quincy Morgan, force a fumble and recover it. They also witnessed a lion jump on the back of a giraffe, a shark gorge a seal and two cheetahs corral a gazelle.

The unusual tape was made by Mark Bienvenu, the team's assistant director of video operations, who spent several weeks culling footage from the Internet and other sources. He found several animal ...