EVER wondered why we have five fingers, not six or seven? By studying mice
with extra digits, a British researcher thinks he has found the answer. If
animals grow more than five digits, he says, their other limb bones get
distorted to such an extent that they can’t walk or run properly, dramatically
affecting their ability to catch prey and flee from predators.
“It seems that five is the maximum,” says Chris Hayes, who studied the
abnormal mice at the Medical Research Council’s Mouse Genome Centre in Harwell,
Oxfordshire. “The growth of other limb bones is compromised to accommodate any…
