Introduction to Marine Mammals

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Introduction to Marine Mammals

• Peter M. Scheifele MDr, PhD, LCDR USN (Ret.)
• University of Cincinnati
• Communication Sciences and Disorders,
  Neuroaudiology Dept.
• University Medical Center
• scheifpr_at_uc.edu

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1. What are Marine Mammals?
2. Introduction to Marine Mammal Taxonomy,
Evolution and Natural History.
Photo Peter J. Auster
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Ancestry can be traced to the Order Artiodactyla
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Phylogeny of Toothed Whales
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Archaic Mysticetes

• Four families of archaic toothed Mysticetes
• Major trends in evolution of Mysticetes
• Loss of teeth
• Large body size
• Large head
• Shortening of neck
• Shortening of intertemporal region
• Telescoped skull with maxilla extending
  posteriorly under the orbits
• Flexible connection between jaws

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Evolution of Cetacean Locomotion
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Evolution in-general
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Part I Marine Mammals Intro
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Marine Mammals- or Who are those Guys, anyway?
PhotosFact File Janett Guiffre Peter M.
Scheifele
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Marine mammals are animals that spend the
majority of their lives in or near the sea

• warm-blooded with back bones that live in water. 
  
• three major groups of marine mammals
• cetaceans,
• pinnipeds,
• sirenians
• Ursidae and the Mustelidae families each have one
  species considered marine mammals
• 115 living marine mammals species
• 76 cetacean species,
• 33 pinniped species,
• 4 sirenian species,
• 1 mustelid species,
• 1 ursid species

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many marine mammals are considered endangered (on
the US Endangered Species list)

• 22 marine mammal species listed on the U.S.
  Endangered Species Act of 1973
• "Endangered species" means any species which is
  in danger of extinction throughout all or a
  significant portion of its range.

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Generalities

• Apparent inability to rear more than a single
  offspring even if twin fetuses occur
• Low reproductive rates
• Fast growth rates
• Low annual mortality rates
• Long life spans
• Highly mobile

A newborn calf weighs about 30-40 pounds
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Part II Taxonomy, Evolution and Natural
History.
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Taxonomic Classification

• Are represented in three mammalian Orders
• Sirenia
• Carnivora
• Cetacea

Photo Peter M. Scheifele
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The Sirenia

• Sea Cows (Extinct)
• Manatees
• Dugongs

Photo from Fact File
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The Carnivora
Polar Bear
Seals and Sea Lions
Sea Otters
Photos From Fact File Courtesy of Mary Laporta
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Not Just Seals, Andre!
Eared / Walking Seals
True Seals
Photos Mary Laporta Edie Brown
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Seals
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Suborders and Families of Cetacea
Photos Peter M. Scheifele
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WHALES AND THEIR RELATIONSHIP TO THE MARINE
ENVIRONMENT
Photos Ivar G. Babb Peter M. Scheifele
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PART 3
Marine Mammal Anatomy / Neuroanatomy
Photo Lesa M. Scheifele
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A dolphin birth
http//www.spawar.navy.mil/sandiego/technology/mam
mals/research.html
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Terrestrial versus Aquatic Mammals

• Humans represent the most highly evolved and
  adapted level of mammal within the terrestrial
  domain.
• Cetaceans and Sirenia represent the only totally
  aquatic mammals, having adapted and evolved from
  once terrestrial animals.
• The anatomical and morphological comparison of
  these two animals clearly shows environmental
  adaptation!

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Adaptations for Aquatic Life

• Skin increased insulation through the
  development of blubber.
• Circulatory System- increased metabolic rates,
  countercurrent heat exchange systems and
  shunting to allow for prolonged deep dives.
• Echolocation- production and hearing of high
  frequency sound for navigation and foraging.
• Limbs- changes to enhance locomotion
• Heavily Lobulated Kidneys- for conservation of
  water and efficiency at concentrating urine.
• Respiratory System- modified to allow for
  prolonged deep dives.

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Sensory Systems

• ODONTOCETES
• Gustatory
• Tactile
• Visual
• Auditory

• MYSTICETES
• Gustatory
• Tactile
• Visual
• Auditory
• Olfactory

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SKELETAL SYSTEM CETACEANS
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Skull

• Primate skull not telescoped with greatly
  inflated cranium and absent rostral area
• Occipital
• Temporal bone and ear are one.
• Skull is symmetrical.
• Two nares.
• Mandible

• Skull is telescoped.
• Occipital bone forms the back of the skull with
  nasal, frontal and parietal bones in between
  (premaxilla and maxilla extend posteriorly and
  laterally such that they override the frontal and
  parietal bones).
• Temporal bone and ear (Bulla) are not connected
• Mysticete maxilla extends posteriorly under the
  orbit.
• Odontocete skull is asymmetrical.
• Two nares in Mysticetes one in Odontocetes.
• Pan Bone present in Odontocetes.

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Circulatory System Functions in Marine Mammals

• Transport of Respiratory Gases
• Heat Exchange
• Diving

Rete Mirabilia
Photo S.H. Ridgway
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BRAIN STRUCTURES Possible Neurological Meaning

• Is relative size of specific areas a definite
  expression of the importance of its principal
  function?
• Past slide preparations of non-perfused brains
  have given only limited data regarding
  architectural arrangements of the cortex.
• Recent advances in anesthesia have allowed brains
  to be perfused in situ for histoarchitectural
  studies.

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SOME GROSS OBSERVATIONS

• Large, unusually shaped
• Well-fissured
• Olfactory bulbs absent
• Radical hypertrophy of acoustic areas

Photo S.H. Ridgway
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Brain Growth

• In man, brain weight at 18 months is roughly
  65-70 percent of adult size and weight.
• In dolphins at 18 months the brain has attained
  80-85 percent of adult size and weight.

Photo Edie Brown
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Drop your reds, drop your greens and
blues(Mick Jagger)
Photo Michel Moisan
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Gustatory Sensation oryou gonna eat all that
yourself?

• Facial nerve is well developed.
• Salivary glands not found.
• Taste buds found within 5-8 pits on posterior
  dorsum of tongue.

Photo S.H. Ridgway
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Dolphin HeadGross Anatomy ofAcoustic Structures
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Beluga Vocal Production Anatomy
Hearing
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Vocalization or Phonation?
Dolphin Larynx showing vocal folds BUT
The Blowhole respiration, vocalization or
both? How do they do it?
Photos J. Reidenberg
and P.M. Scheifele
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Selected Signals 1
Whole signal in noise (cut)
Low Pass (noise) NL
High Pass
Bandpass (signal) VL
whisE1715
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Whale Ears are NOT Typical
Middle ear bones
Inner ear
Inner Ear Bone (bulla)
Cochlear anatomy similar to humans
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What a long strange trip its been (Jerry
Garcia)
Photo Edie Brown
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Part IV Current Issues Facing Marine Mammals
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Current Issues

• Oil Spills
• Encroachment of human populations
• Whaling and seal hunting
• Ecotourism
• Noise
• Commercial
• Research
• Military Sonar
• Ecotourism
• Fisheries
• Disease

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Oil Spills

• Species Affected- All
• Exxon Valdez was NOT the first!
• Ship design
• Oceanic drilling
• OPA - 90

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Human Interactions

• Species Affected All
• Shipping ship strikes
• Encroachment
• Pollution
• Captivity
• Boating / waterways
• Mining / drilling

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Whaling and Seal Hunting

• Species Affected Carnivores Cetaceans
• What is take?
• International Whaling IWC
• Takes by native peoples

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Eco-Tourism

• Species affected- Cetaceans, Pinnipeds
• Whale watching
• Swim-with programs

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ACOUSTIC ISSUES FACING MARINE MAMMALS
Oil Drilling Exploration
Mining Dredging
Commercial Shipping
Scientific Exploration
Military Sonar
Commercial Fishing
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Ship Noise The New Threat
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Whale Watch Vessels
Photos Peter M. Scheifele
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Transportation Vessels
Photo Peter M. Scheifele
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Fisheries

• Species affected- Cetaceans Pinnipeds
• Commercial fishing
• Tuna in ETP
• Gillnets draggers
• Depletion of food stocks
• Aquaculture
• AHDs

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Fini