Summer of the Shark

1. SENSING
A network of pores connected to long canals spread across the head enables a shark to detect weak electrical field that small fish and other sea creatures create as they breathe

2. SMELLING
A shark has a fairly acute sense of smell; it can detect concentrations of blood as low as 1 part per million

3. SEEING
Like a cat, a shark has a special reflective layer behind the retina that helps it see in dim light. A shark must move its head from side to side to see objects directly in front

4. HEARING
Tiny holes on top of the head lead to very sensitive ears. Three semicircular canals in the inner ear help maintain balance. A shark might be able to pick up the sound of a struggling fish about 600 yards (550 m) away

5. SKIN
A shark's skin is covered with a protective layer of microscopic, toothlike scales called denticles. Like the teeth, they are pointed, covered in enamel and contain a nerve. They also are shed and grow again

6. LATERAL LINE
A series of pores with vibration-sensitive hair cells at their base runs along the shark's sides, another way to sense the environment