1. Whales

2. • Evolved from land mammals 50 to 65 million
years ago
• Evolved from ungulates
(related to horse and sheep)

3. Temperature Regulation
• Blubber (also for buoyancy and energy storage)
• Counter-current blood flow –
warms blood as it returns to
core of body
• Muscles generate heat
• Low surface area to volume
ratio - little surface in contact
with water to lose heat

4. Oxygen
• blowhole (nostrils) on head – easier
• Empty and fill lungs quickly (2 seconds for a fin
whale)
• Large lungs
• High gas exchange rate (absorb 90% of oxygen
- humans absorb 20%)

5. Oxygen
• Many red blood cells, hemoglobin – carries
oxygen
• myoglobin - carries additional oxygen
• Shunt blood from non-vital organs (stomach,
kidney) when diving to vital organs (brain,
heart, muscles)
• Slow heartbeat rate when diving

6. Propulsion Through the Water
• Streamlined
• Internalized body parts - ear, penis, mammary
glands – reduces friction
• Shorter appendages – forelimbs for steering
• Loss of hind limbs
• Loss of hair

7. Propulsion Through the Water
• fluke (tail) for propulsion
– Up and down (unlike fish = side to side)
– ↑ surface area
– Also to identify individuals - like fingerprint
• flippers – for steering and balance

8. Sensing the Environment
• Good eyesight – but little to no light
• echolocation - biological SONAR – find and
maybe to stun prey
• Very good hearing - sound travels faster in
water than in air
• ex: humpback songs for communication –
social, territorial

9. Pressure
• Collapsible lungs
• Nostrils close to prevent water from entering
• Do not get the bends
– when we dive if ascend too quickly, dissolved
nitrogen forms bubbles – pain, embolism, death
• Tissues and blubber have higher affinity for
nitrogen

10. Types of Whales
• Toothed whales – suborder Odontoceti
• Baleen whales – suborder Mysticeti

11. Types of Whales – Toothed Whales
• Have teeth – to catch prey, not chew
• Eat mostly fish and squid - killer whales eat seals
• Dive deeper
• Most do not migrate
• Ex: sperm, pilot, killer whales, dolphins, porpoises
• Ex: sperm whales dive > 3,500 feet for giant squid,
up to 75 minutes

12. Types of Whales – Baleen Whales
• No teeth - 600 - 800 baleen plates to filter krill
and other items
• ex: blue whale eats 4 tons of krill per day
• Not deep divers
• ex: humpback - lung feeding (lunge forward,
pleats open), flick feeding (flick tail), bubble
feeding (blow bubble net and swim up)

13. Types of Whales – Baleen Whales
• pleats – folds under mouth
– open like accordion when feeding

14. Types of Whales – Baleen Whales
• ex: humpback - lunge feeding (lunge forward,
pleats open), flick feeding (flick tail), bubble
feeding (blow bubble net and swim up)

15. Types of Whales – Baleen Whales
• ex: blue, humpback, right, gray, fin
• North to feed, south to breed - behavioral
adaptation
– north - summer for krill
– south - winter to raise young
• ex: gray whales, 3 month
migration, Arctic to Baja, CA,
6,000 mi one way

16. Reproduction
• coincides with migrations
• internal fertilization
• live young born
• nurse and grow quickly, ex: blue whale, 130 gal
milk/day, grows 200 lbs./day
• low birth rate
• pods – family groups of whales - social

17. Whale Behavior
• Breaching – jumping out of water
– to remove parasites, social behavior, stun prey?
• Spyhopping – sticking head out of water
– curiosity, look for prey, communication?

18. Whale Behavior
• Beaching – swimming up onto beach
• Can be one or many individuals
• Cannot hold up body on land
• Reasons – noise pollution, disease, injured,
red tide, anomalies in magnetic field, lost?

19. Whaling
• Hunted by indigenous people
• Problems starting in 1600s –
industrial whaling
– not for food
– blubber – oil for lamps and soap
– baleen – anything we use plastic for today –
combs, umbrellas

20. Whaling
• Low reproductive rates – one young every 2 to
3 years
• Could not withstand whaling pressure
• Better technology made things worse - factory
ships, harpoons

21. Whaling
• International Whaling Commission (IWC)
group of countries to regulate whaling
industry
• Marine Mammal Protection Act – 1972 – U.S.
law – bans hunting and harassment of all
marine mammals