Marine Mammals

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Marine Mammals

• Whales

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Order Cetacea 90 species

• Whales are different from seals and sea lions
  because they spend their entire lifespan in
  water.
• There are two main groups of whales
• 1. Toothed whales
• 2. Baleen whales

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Toothed whales

• Examples killer whales, pilot whales, dolphins,
  porpoises, sperm whale
• one blowhole opening
• eat one prey item at a time/swallow prey
  whole
• feed in the entire water column

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Baleen whales

• Examples gray whale, blue whale, right whales,
  humpback whale
• 2 blowhole openings
• toothless feed with baleen which is made from
  keratin. It is a food filtering system. When
  water is pushed out of the mouth the krill are
  trapped!
• Keratin is the same
• protein found in hair
• and fingernails.
• (like stiff straw)
• They eat krill
• (2 inches)/plankton
• Feed at the surface
• Gulpers vs. skimmers

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Comparing Toothed and Baleen Whales
Ventral pleats expand when water is taken into
the mouth (found on baleen whales only).
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Movement

• Whales move with an up and down movement of the
  fluke (powerstroke). Upward movement provides
  the power! This is different than fish which use
  a side to side motion.
• Spyhopping vertical upward movement to look
  around.
• Breaching Jumping out of the water.

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Echolocation

• Sound travels 4X faster in water than air. Used
  by whales to communicate. (we will talk about
  this is more detail when we do notes on dolphins)

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Diving

• To dive whales..
• 1. Hold breath
• 2. Rapidly exhale (90 of Oxygen exchanged
  compared to 20 in humans)
• 3. Take a new breath DIVE!
• Sperm whales 2 hour dive time
• Blue whales 40 min dive time
• Bottlenose whales (dolphins) about 15 min.

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Diving facts

• 1. Baleen whales dont dive deep! Why?
• A Because plankton/krill are found at the
  surface
• 2. Whales have more R.B.Cs than non-diving
  mammals.
• 3. When whales dive their heart rate slows
  dramatically from 85 down to 12 per minute.
• 4. Blood flow to nonessential organs is reduced.
• 3 and 4 together are called bradycardia.
• 5. Nitrogen dissolves better at high pressure
• ex. Think of the lungs like a pop bottle -
  lungs collapse squeezes air to central part of
  lung where little Nitrogen is absorbed. Oxygen
  goes directly to blood.