Marine Mammals:Part 3

Marine Vertebrates: Lecture 9

Cetacea OriginsArchaeocetes (~50 mya)

• Pakicetus Long, slender

jaws Simple teeth Dorsal blowhole Robust pelvis and

hindlimbs

Cetacea OriginsArchaeocetes (~50 mya)

•Basilosaurus More obviously aquatic Reduced hindlimbs

Order CetaceaSuborder Mysticeti

Overview

•Baleen

•Head

•# of species

•Location/ feeding

Right whale baleen; photographer unknown

Order Cetacea: Suborder Mysticeti

Family Balaenidae• Large heads• Bowed (highly

curved) mouth Adaptive value? Characteristics of

baleen?• Fins

No dorsal Small pectoral fins

• Primarily known to feed on copepods

Feed by skimming

Order Cetacea: Suborder Mysticeti

Family Balaenidae: bowhead whale

Bowhead whale; artist unknown

• Arctic Follows cycle of ice Most northerly

Mysticeti

• Hunting began ~1600, near extinction by 1900

Slow recovery Inuit hunting

• Head may be up to 40% of body length

• Baleen highly valued

Silky and Long

Order Cetacea: Suborder MysticetiFamily Balaenidae: Southern right whale

Southern right whale: Photo: Ocean Alliance

• Callosities

•Why called right whales?

• Two species

• Current status

Callosity close-up: Whale lice and barnacles on a right

whale

Whale licePhoto: Vicki Roundtree

Photo: Iain Kerr Ocean Alliance

Order Cetacea: Suborder Mysticeti

Family Eschrictiidae: Gray whales

Gigi the Gray WhalePhoto: Ron Church

• Where found?• Key Features

Relatively slender Whale

lice/barnacles Throat grooves (2-

7) Bottom feeders

• Method? Key food?

• Migration • Once near

extinction• Recovery

Removed from U.S. endangered species list in 1994

Order Cetacea: Suborder Mysticeti

Family Balaenopteridae

Humpback Whale,Photo: K. Haberman

• Throat grooves: expansion during feeding• Depressed frontal bones• Small, posterior dorsal fin; flipper size varies• Relatively fast

Order Cetacea: Suborder Mysticeti

Family Balaenopteridae: minke whale

Minke Whale, Project Atlantis

• Worldwide distribution• To whale or not to whale?• Antarctic populations feed on…krill!• Northern pops feed on krill & fish

Order Cetacea: Suborder MysticetiFamily Balaenopteridae: humpback whale

Humpback WhalePhoto: H-C travel

• Worldwide distribution Migrate cold water

(feed) to tropics (breed) Feed on krill and fish

• Huge pectoral fins• Distinctive white

patches • Scars, barnacles and

cookie-cutter bites• Distinctive behaviors…• Conservation status:

vulnerable Hunted by Carib natives

Whale songs

How produced? Which ones sing? Singing posture Song length Changes over time

Order Cetacea: Suborder MysticetiFamily Balaenopteridae: blue whale

Blue WhalePhoto: Project Atlantis

Blue whale facts• Distribution: Once worldwide; now largest

populations are off coast of _____? • Migrate to tropical waters for calving

In some tropical areas, blue whales are seen year round• Why might this be?

• Largest animal ever Up to 24.5 meters (female); Mouth alone of 6 meters;

190 tons Heart the size of a VW bug Spray from blow is about 6 meters high. Larger prior to mechanized whaling

• Only hunted after the development of the grenade harpoon (1800s)

In one year, 30,000 were killed (not sure which year)

• Loudest,deepest voice of any animal: 180 dB, 10 Hz

• Diet is almost exclusively…???