The predators are winning .... this time :)

KILLER DRILLERS  Predators such as moon snails (Naticarius orientalis shown) that kill by drilling through other animals’ shells offer a rare chance to test an idea about the power of enemies.

The predator/prey arms race has been around for a very long time as seen by the chart below and by data garnered by researchers regarding, in this case, shell drillers of the carnivorous kind. 

“Predators got bigger — three words!” is Klompmaker’s bullet point for the work. Over the last 450 million years or so, drill holes have grown in average size from 0.35 millimeters to 3.25 millimeters, Klompmaker and an international team report June 16 in Science. Larger holes generally mean larger attackers, the researchers say, after looking at 556 modern drillers and the size of their attack holes.

Prey changed over millennia, too, but there’s no evidence for a shift in body size. The ratio of drill-hole size to prey size became 67 times greater over time, the researchers conclude.

It’s “the rise of the bullies,” says coauthor Michal Kowalewski of the University of Florida in Gainesville.

Nature, like money, never sleeps.

Bigger and bigger

Drill holes (example from a shell about 4 million years old from the Netherlands, left) tended to get larger in relation to the size of the attacked shell as the periods in geologic history marched by (graph, right). This trend and other ways of analyzing drill holes suggest predators outpaced their prey in body size.