©1996, west publishing company (modified by asper, 2006) slide 1 lesson #7 what eats fish: mammals...

©1996, West Publishing Company (Modified by Asper, 2006)©1996, West Publishing Company (Modified by Asper, 2006) Slide Slide 11

Lesson #7What eats fish: Mammals and birds

Developed by Vernon Asper

And Linda Martin

USM


What are mammals?

• All Mammals:– have lungs & breathe air– warm-blooded & maintain a constant body

temperature– most bear live young– produce milk &

nurse young– have hair at

some point during life


Marine mammal are those which live in a marine environment

Cetaceans

dolphins, whales, porpoises

Pinnipeds

Seals, sea lions, walruses

Sirenians

Dugongs, manatees

Others

Sea otters, polar bears

http://nmml.afsc.noaa.goveducationmarinemammals.htm


Order #1: Cetaceans

Whales, dolphins, porpoises

• Live entirely in the water

• streamlined bodies have thick layers of blubber (fat)

• Flippers for front limbs

• No hind limbs

• Almost no hair

• Modern cetaceans divided into two

suborders:

baleen whales and toothed whales


Cetaceans: Baleen Whales

• Largest animals in the ocean

• Spend summers in high latitudes where the krill (their main food) is plentiful, build up blubber for a few months

• Migrate to warmer waters to breed, live off blubber during breeding

Blue, fin, gray, humpback, sei,

and roqual whaleswww.montereybaywhalewatch.com/


Cetaceans: Baleen Whales• Use baleen to feed

– consists of plates of keratin – (the same stuff you fingernails are

made of)– plates hang in mouth like the bristles

of a broom– to feed, they take in a mouthful of

water and food, push the water back out through the filter with their tongue

www.ifawct.org


Cetaceans: Baleen Whales cont’d

• Baleen was used for a lot of things that we use plastic for now

• It was once used for corset stays

• It is still used in some industrial businesses

costume.dm.net


Cetaceans: Toothed Whales

• Smaller than baleen whales• Have anywhere from 1-65

teeth depending on the species• Slicing teeth• Throats large enough to swallow

chunks of giant squid, cuttlefish,

etc.• Single blowhole• Use “echolocation”

Dolphins, porpoises, narwhals

Beluga, killer, pilot, and sperm whales

http://nmml.afsc.noaa.gov


Echolocation

• Toothed whales use sonar to “see” in dark or murky water

• Just like a ship’s sonar, they bounce sound off of objects and interpret the echoes: Dolphin Pilot Whale Sperm Whale

• They can judge distance, speed, size and composition, all from the echo!


Cetaceans: Toothed whales

• Dolphins:– hooked dorsal fin

– Beak (snout)• Tapered head

– Gregarious; travel in pods

– Enjoy bow riding

• Porpoises:– Triangular dorsal fin

– No beak• Blunt head

– Usually solitary

– Avoid vessels

Dahl’s Porpoise: www.theporpoisepage.com


Bottle Nose Dolphin Interesting Facts:

• Most researchers agree that dolphins exhibit a level of intelligence greater then that of dogs and even comparable to that of some primates--but not human beings.

• Dolphins can hold their breath for up to several minutes and are capable of rapid and deep dives of more then 1,000 ft.

• A female dolphin can potentially bear a calf every two years, but calving intervals generally average three years.


Order #2: Pinnipeds

• Often come out of the water– Rest– Mate– Give birth– Molt (shed old fur)

• Stay crowded together in large groups

• Members of certain groups return to the same beach year after year

Seals, sea lions, walruses

• Males – bulls• Females – cows• 1 bull + multiple cows = harem• 3 subgroups: earless seals, eared seals, walruses



Earless (crawling) seals

• Largest group

• No external ears

• In the water– Fast, agile swimmers– Side to side strokes of hind flippers

• On land– Drag by front flippers– Wiggle on bellies

Elephant, harbor, harp, leopard seals

www.bbc.co.uk/


Gory slide alert!Close you eyes if you don’t want to see it!

• Leopard seals are aptly named!

www.birdinfo.comwww.birdinfo.com


http://http://www.factzoo.com/www.factzoo.com/mammals/seals/mammals/seals/leopard-seal-fearsome-leopard-seal-fearsome-penguin-predator.htmlpenguin-predator.html


Eared (walking) Seals

• Longer, more flexible neck

• Longer flippers

• Small ear flaps

• In the water– Use front flippers to

swim

• On land– Turn hind flippers forward; walk on all fours

Fur seals, sea lions



Walruses• Only living species of its family• Long downward tusks that can

reach 3 feet and 12 pounds• Males grow up to 12 feet,

2800 pounds• No external ears• Deeply folded skin

over

shoulders

www.dolphintrainer.com

http://collections.ic.gc.ca/arctic/species/walphoto.htm


Walruses cont’d• Found in relatively shallow waters of the

arctic seas of Eurasia, North America• Live on ice floes in groups of up to 100• Eat mostly shellfish• Sometimes dive deep in search of food• Follow ice line S in winter and N in summer• Commercially hunted for

centuries, now generally banned

www.alaskawalrusisland.com


Order #3: Sirenians

• Only marine mammal herbivores

• Live in shallow, warm water

• Slow swimmers

• They have blubber, but not for warmth– Food storage for when food is scarce

Manatees, dugongs, sea cows

www.gbrmpa.gov.au


Sea Cows• Discovered in 1741 by a

member of Vitus Bering’s expedition

• Lived around islands in the Bering Sea

• No teeth, small head, broad horizontal forked fluke• Dark brown with

white streaks or spots

* When sea cows were discovered, it was estimated that their population was around 5,000. Because Russian sealers hunted them so much for food and for their fur, just 27 years later, in 1768, they were extinct!!

www.sirenian.org


Manatees

• Tapered body, ending in a rounded flipper

• Fore flippers near head

• No hind flippers

• Adults can be 8-15 ft & up to 1500 pounds

• Live singly or in small herds

• Protected by law in most areas

• Found in SE United States, N South America, and W Africa

www.floridaconservation.org/


Dugongs

• Found in the Red Sea, East Africa, the Philippines, New Guinea, and North Australia

• Rounded body ends in a flipper with paired, pointed, horizontal branches

• No hind limbs

• Head blends into the body

• Broad, square, bristled snout

http://sea-dugong.org/


#4: Other Marine Mammals

There are two other animals that fall under the “marine mammals” classification:

* sea otters

* polar bears


DANGER!!!!!

• Most marine mammal dangers are caused by people

• Pollution, over fishing, boat collision • Oil spills, plastic trash,

poisons• Fishing:

– competition for food– get caught in fish nets and drown

• Many endangered species– Manatees, monk seals, stellar sea lions, many baleen

whales

www.floridaconservation.org/


• Dolphins stranded since the oil spill (April 22, 2010)http://www.nmfs.noaa.gov/pr/health/mmume/cetacean_gulfofmexico2010.htmhttp://www.nmfs.noaa.gov/pr/health/mmume/cetacean_gulfofmexico2010.htm


Oceanic Birds: Albatross

• The Albatross is almost as much a marine animal as a whale

• They spend months wandering great distances over the oceans.

• They sleep while floating on the ocean surface, drink seawater, and feed on cuttlefish, other small marine animals,



• They return to land only to breed• Well-known species include the wandering

albatross, a huge bird with a 3.4 m (11 ft) wingspread.


Oceanic Birds: Albatross• Albatrosses nest on barren islands,

close to shore; usually the nest is a depression in the ground containing a single egg.

• Albatrosses are relatively fearless around humans, who have nicknamed the birds "gooneys."



• Nesting sites near military airstrips on small islands have sometimes created problems because of the birds' interference with takeoffs and landings.

• There is a superstition commonly held by sailors that killing an albatross brings bad luck.

• The superstition forms the theme of "The Rime of the Ancient Mariner”


Oceanic Birds: Penguins

• Penguins are true marine animals also;– They only come on

shore to breed– The rest of the time

they are in the water or on the ice

• The Adelie is the "classic" penguin

• They resemble that "little guy in a tuxedo."


Oceanic Birds: Penguins

• Adelie penguins average around 8.5 pounds and are on the shorter end when compared to other penguins since they average around 15 inches.

• The male and the female can be distinguished only by behavioral and temporal cues during the mating season.


Adelies can Really Swim!


Oceanic Birds: Penguins• Adelies, like most penguins, return to the same breeding grounds every year• These “rookeries” are jam packed with penguins at this time• There is nothing to eat there and they make their nests out of rocks because there are

no plants


Oceanic Birds: Penguins• The diet of the Adelie consists of small fish and various

crustaceans• These animals, in turn, feed on zooplankton, which feed

on phytoplankton• So, like other marine animals, they are completely

dependent on phytoplankton for food.


Emperor Penguins

• These are the “March of the Penguins” birds


Emperor Penguins

Clumsy on land, they are incredible under water!

http://www.nsf.gov/od/lpa/news/02/images/emperors.jpghttp://www.nsf.gov/od/lpa/news/02/images/emperors.jpg


Emperor Penguins• Breed at locations far from open water

• Have to “march” a long way to get there

• Do it

in the

winter

• Not

an

easy

life

http://www.nsf.gov/od/lpa/news/02/images/emperors.jpghttp://www.nsf.gov/od/lpa/news/02/images/emperors.jpg


• One egg is produced each year

• The male and female take turns tending it.

• Young must fend for themselves before the end of summer

http://www.emperor-penguin.com/big-chick.htmlhttp://www.emperor-penguin.com/big-chick.html


Antarctic food web

• All life in Antarctica relies on plankton

• No grass or trees

• Growing season lasts for 2 months

• Very specialized organisms


Bottom dwellers (benthos) rely on food from the surface

Depth (meters)Depth (meters)Altitude (meters)Altitude (meters)


Summary

• Marine mammals and birds are those which spend their lives in the ocean

• They have most of the characteristics of their terrestrial relatives but are designed for life in the water

• Mammals include otters, seals, manatees, dolphins, and whales, to name a few.

• Oceanic birds spend most of their lives in or on the water and derive their sustenance

• All life in Antarctica relies on the ocean for sustenance.

©1996, west publishing company (modified by asper, 2006) slide 1 lesson #7 what eats fish: mammals...

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