Marine Mammals:Part 4

Marine Vertebrates: Lecture 10

Order CetaceaSuborder Odontoceti

• Teeth Simple teeth

• Single roots • conical crowns

Increase # of teeth (some)

Some with highly derived teeth or secondary loss of teeth • Example: sperm

whales

Scrimshaw; Robert Schoen

Pygmy sperm jaw; Arizona dry bones

Order Cetacea: Suborder OdontocetiFamily Physeteridae, sperm whales

Sperm WhaleArtist unknown

• Distribution

• Physical characteristics

Head Fins Body size

• Spermaceti organ

• Feeding ecology

• Conservation Most hunted whale

• Why so valuable?

Order Cetacea: Suborder OdontocetiFamily Kogiidae, pygmy sperm whale

Pygmy Sperm WhaleT. Komakko

• Similar head and oil as sperm whale• Not as large, and also not as elongate• Similar diet as sperm whales

Use of bioluminescent squid ink as defense!

Order Cetacea, Suborder OdontocetiFamily Monodontidae, narwhals and belugas

NarwhalA. Martin

BelugaU.S. Navy

Order Cetacea, Suborder OdontocetiFamily Monodontidae, narwhals and belugas• Distribution

Circumpolar, arctic only Migrations linked to advance and retreat

of the pack ice.

• Physical characteristics Small whales, up to ~5m Blunt head, small mouth, no dorsal fin,

small pectorals Narwhal’s tusk (♂) is a modified tooth; ♂ -

♂ competion

• Feeding ecology The two species have complementary

distributions and feeding behaviors

Order Cetacea: Suborder OdontocetiFamily Delphinidae: dophins

Bottlenose dolphinPhotographer unknown

• Most diverse group of Cetacea

33 species

• Primarily fish and squid eaters, but…

• Teeth• Fins• Pointed beak (in

some)• Elaborate social

systems

Order Cetacea: Suborder OdontocetiFamily Delphinidae: bottlenose dolphin

Bottlenose dolphinPhotographer unknown

• Distribution Range: Worldwide, Often in warm,

shallow inshore waters

Associate in schools from 10-500

May travel long distiances• No distinct migratory

patterns

• Speeds up to 19 mph.

Order Cetacea: Suborder OdontocetiFamily Delphinidae: bottlenose dolphin

Bottlenose dolphinPhotographer unknown

• Feeding ecology How do they find food? What do they eat?

• Other distinctive behaviors

Hold young and injured at surface to breathe• May increase deaths in

nets

• Conservation status Classified as

“threatened” by IUCN

Order Cetacea: Suborder OdontocetiFamily Delphinidae: Pacific white-sided dolphin

Pacific white-sided dolphin Photo: Peggy Stap

• North Pacific• Nocturnal feeders: squid and fish• Large pods (100 or more)

Spinner dolphin Photo: Andre Seale

Photographer unknown

Order Cetacea: Suborder OdontocetiFamily DelphinidaeSpinner dolphin• Worldwide, tropical

and subtropical local “races”

• Found among schools of yellowfin tuna

• Spinning behavior Communication to

help aggregate? Parasite or remora

removal?

Tuna-dolphin issue

•Dolphin-safe?

Order Cetacea: Suborder OdontocetiFamily Delphinidae

OrcaPhoto: NOAA

Order Cetacea: Suborder OdontocetiFamily Delphinidae

OrcaPhoto: NOAA

• Distribution: Worldwide

• Pods/group size

• Physical characteristics

Teeth Dorsal fin

• Feeding ecology

• Conservation status Local Puget Sound pod

= endangered Captivity issue

Order Cetacea: Suborder OdontocetiFamily Phocoenidae: porpoises

Harbor porpoisePhoto: Riverhead Foundation

• Compare w/Delphinidae

Spade-shaped teeth Triangular dorsal fin No pointed beak Small compared to

delphinids

• Focus: harbor porpoise Distribution: Northern

Hemisphere, temperate to subarctic waters

Common, but rarely seen on surface

Diet• A variety of fishes• calves will eat…krill!

Order Cetacea: Suborder OdontocetiFamily Zephiidae: Beaked whales

Beaked whalePhoto: Nan Hauser

• Overview Teeth reduced

or absent• Examples…

• Feeding ecology Squid!

• Conservation status

Most species are rare• Strapped whales

known only from strandings