from the book, "Our Fascinating Earth"
In 1968 a 12—foot black mamba went on strike at the Transvaal Serpentarium. Resisting attempts of inept attendants to "milk" it for its venom, it bit one of the workers on the wrist. The worker was hurried off to the hospital, where quick medical treatment with mamba serum barely managed to save his life.
Back in its glass pen, the mamba reared up and struck at the glass every time anyone came within vibrating distance. The director of the serpentarium was concerned that the mamba would damage its fangs and become useless for milking. After all, he has paid the equivalent of $1.50 per foot for this particularly deadly reptile, and any damage to its fangs would mean sacrificing his investment. To distract the nettled mamba, the director ordered a chunky white mouse thrown into the snake's pen as a snack.
Normally a frightened mouse would capture the attention of a hungry mamba, even one with an aching mouth. But the stratagem got off to a bad start. The mouse, far from being terrified, ran up to the rearing snake and bit it firmly on the side. The rodent then retired to a neutral corner, completely ignoring the snake, and busied itself feeding on scraps in the pen and cleaning its whiskers. Two days later it was still finding scraps and grooming itself, but it was alone in the pen. The deadly black mamba had died of infection from the mouse bite!