Rats

The rat's nutritional requirements are similar to those of humans, which makes it a useful subject for scientific experimentation. They have been known to carry off beef bones left by picnickers, eating not only the remaining meat but also the bone as well, for the calcium and phosphorus it provides.

Rats will eat just about anything, including things that humans would consider far past being edible. However, they prefer grain and consume or spoil (by their hair and droppings) millions of tons of stored food each year worldwide.

Rats possess remarkable physical abilities. Rats can: swim for half a mile, and tread water for three days; survive falling five stories and run off unharmed; fit through a hole the size of a quarter; and scale a brick wall. Years after the nuclear testing ceased on Engebi Island in the western Pacific Ocean, scientists found rats, "Not maimed or genetically deformed creatures, but robust rodents so in tune with their environment that their life spans were longer than average," one researcher observed.