Lecture Notes: Fascinating Facts About Whales

Introduction

• Whales are fascinating marine mammals with specialized features.
• Whales belong to the order Cetacea, which splits into two subgroups: toothed whales and baleen whales.

Key Characteristics of Whales

• Whales are mammals:
  • Give birth to live young.
  • Nurse with milk.
  • Warm-blooded and covered in hair (lanugo as young, some retain hair as adults).
• Cetaceans evolved from ancient land mammals that returned to aquatic life about 50 million years ago.

Evolutionary Adaptations

• Nostrils migrated to the top of their heads:
  • Baleen whales have two blowholes.
  • Toothed whales have one blowhole.
• Male whale anatomy (backbones anchor the penises) reflects evolutionary history.
• Whale ears:
  • Adapted for deep diving; no external ear canals.
  • Earwax buildup allows scientists to study age, diet, and hormones.

Toothed Whales

• Use echolocation for hunting and navigation.
• Echolocation process:
  • Clicks made in nasal passages.
  • Focused by the melon.
  • Received by fatty tissues in the lower jaw, transmitted to inner ear.

Baleen Whales

• Famous for complex songs (humpbacks).
• Feeding:
  • Filter feed using baleen plates.
  • Rorqual whales expand mouths to gulp water and filter food.
  • Bowhead whales filter water without fully opening jaws.

Unique Whale Species

• Narwhals:
  • Known for their tusks (elongated canine teeth).
  • Use debated among scientists; possibly sensory or mating attributes.
  • Tusks used by Inuit for tools.

Whales in the Ecosystem

• Whales’ role in nutrient cycling:
  • Deep ocean feeders that fertilize surface ecosystems with iron-rich poop.
  • Sperm whale poop helps sequester carbon.

Record-holding Whales

• Cuvier’s beaked whale: dives up to 3,000 meters.
• Bowhead whales: estimated lifespan up to 200 years (evidence from embedded harpoons).

Whale Falls

• Dead whales create ecosystems in deep sea as their bodies decompose.
• Support various deep-sea organisms, including zombie worms.

Additional Information

• Announcement of upcoming ocean-related content from Monterey Bay Aquarium and PBS/BBC event.
• Stay Curious: Encouragement to explore and learn more about ocean life.

Space Exploration Note

• A brief mention of spacecraft, unrelated to whales, focusing on New Horizons’ journey to Pluto.