Bluntnose Sixgill Shark: a two-minute wildlife lesson

Coral Reef · day 3 of 7

Five facts

1. A bluntnose sixgill's pupils are black, but its eyes are a fluorescent blue-green.
2. Six gill slits give the sixgill its name. Most common sharks today have only five.
3. Off Hawaii, 4 sharks swam up to 300 m between midnight and 3 AM, then dropped to 600-700 m around noon.
4. Sixgills are positively buoyant, so they can glide upward and sneak up on prey from below with minimal movement.
5. A sixgill litter is large, typically 22-108 pups, each 60-75 cm long at birth.

The quiz

1. What colour are a sixgill's eyes?

• Bright red
• Fluorescent blue-green (correct)
• Pale yellow
• Solid black

Its eyes glow a fluorescent blue-green around black pupils.

2. How many gill slits do most common sharks have?

• Five (correct)
• Three
• Seven
• Eight

Most common sharks have only five gill slits.

3. About how deep did the sharks go around noon?

• 6-7 m
• 60-70 m
• 600-700 m (correct)
• 6,000-7,000 m

Around noon they dropped to 600-700 m.

4. What lets sixgills glide upward and sneak up on prey from below?

• Positive buoyancy (correct)
• Powerful tail beats
• Bright eyes
• A warm body

Positive buoyancy lets them glide upward with minimal movement.

5. How long is a sixgill pup at birth?

• 6-7 cm
• 6-7 m
• 160-175 cm
• 60-75 cm (correct)

Pups measure 60-75 cm at birth.

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