Duck

Ducks are so common and unthreatening that almost nothing about them gets a second look. They turn out to have bills packed with sophisticated touch receptors, brains capable of abstract concept learning within hours of hatching, and a behavioral complexity that ranges from coordinated sleep to abstract thinking. The humble duck is a genuinely surprising animal.

Facts you didn't know

• 1

  A duck's bill is densely packed with mechanoreceptors — sensory cells similar to those in human fingertips — allowing ducks to identify food by touch in murky or dark water. They feel for food rather than seeing or smelling it, with a sensitivity comparable to a blind person reading braille.

• 2

  Duck quacks do echo. The persistent myth that they don't was tested and disproved by acoustic researchers at the University of Salford. The confusion comes from the duck quack's gradual fade, which makes the echo difficult to distinguish from the tail of the original sound — but under controlled conditions, it echoes clearly.

• 3

  Ducks sleep with half their brain at a time. Those on the edge of a sleeping group keep the outward-facing eye open — connected to the alert hemisphere — while the inward eye rests. Ducks in the center of the group sleep with both hemispheres. They physically position themselves to assign the perimeter duty.

• 4

  Ducklings shown two different objects simultaneously can imprint on the abstract concept of 'same' or 'different,' then apply it to entirely new objects they've never seen. Abstract concept learning within hours of hatching — before they've had time to learn much of anything.

• 5

  Female ducks have evolved corkscrew-shaped vaginal canals that rotate in the opposite direction to the male's corkscrew anatomy, giving females physical control over fertilization outcomes. The counter-rotating anatomy is the evolutionary result of an anatomical arms race playing out over millions of years.