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					         Orders Not Yet Discussed
Cetaceans. These aquatic mammals—whales, dolphins,
    porpoises, etc.– include the largest animals ever known.
Rabbits. These small herbivores are built to move fast, and they
    exploit cellulose by a double-cycling, hindgut-fermentation
    strategy.
Hyraxes. These small African herbivores are distantly related to
    elephants and to sea cows.
Sea cows. Manatees and dugongs are large, entirely aquatic
    herbivores.
Elephant shrews. These are small African insect-eaters,
    typically with monogamous mating systems.
Tree shrews. Once thought closely related to primates, these
    Southeast Asian mammals are mostly insect-eaters.
Colugos, flying lemurs, or dermopterans. These arboreal
    animals of the Southeast Asian rainforests are the best
    gliders in the Class Mammalia.
Aardvark. This African mammal exploits colonial insects and is a
    world-class digger.
Today we have a grab-bag of leftovers…
                            Whales




•   Large to very large, entirely aquatic mammals.
•   Two living Suborders (baleen & toothed); 1 extinct Suborder.
•   About 10 Families.
•   About 78 species.
•   Often inhabit higher latitudes (in summer), where long daylight
    & concentrations of dissolved O2 produce abundant life.
Phylogenetic relationships of Whales
                        • Archaeocetes
                          are extinct.
                        • Baleen whales
                          are large & form
                          a coherent
                          group defined by
                          foraging
                          technique.
                        • Modern ―toothed
                          whales‖ are a
                          diverse group,
                          ranging from
                          smallish to very
                          large.
                               Whales, etc.
                               Common      # of     # of    distribution
Suborder     Family            name
                                           genera   species
             Balaenidae        Right         2         3     All oceans except
Mysticeta                      whales                        tropical & Antarctic
                               Gray          1         1     N. Pacific, coastal
             Eschrichtiidae
                               whales
                               Rorquals      2         6     All oceans
             Balaenopteridae

             Platanistidae     River         4         5     Oriental & Neotropical
Odontoceta                     dolphins                      rivers
             Delphinidae       Dolphins      16       31     All oceans & major seas


                               Porpoises     3         6     All oceans except
             Phocoenidae
                                                             Arctic & Antarctic
             Monodontidae      Narwhal &     2         3     Arctic Ocean &
                               beluga                        adjacent big water
             Physeteridae      Sperm         2         3     All oceans
                               whales
             Ziphiidae         Beaked        6        18     All oceans
                               whales
     Thoughts on whale evolution
• The earliest whale fossils are from the Eocene,
  perhaps about 50MYBP.
• Some primitive whales had external rear legs (no
  modern whales do), and all early varieties had teeth.
• The relationship between whales and other mammals
  is now well established:
  – A few authorities once classified whales in a loose group
    with elephants-hyraxes-sirenians, or even w/ perissodactyls.
  – At one time some biologists thought that toothed whales had
    their own separate ancestry, from carnivores.
  – Now most mammalogists with any sense believe that all
    cetaceans are distantly related to hippopotamid artiodactyls
    (next slide).
Whale ancestry
      • Of course whales are highly
        derived, so affiliations are not
        obvious from fossils.
      • However, by 1880’s clever
        mammalogists noticed foot
        similarities between
        atriodactyls and animals like
        Ambulocetus.
      • In 1950, Boyden & Gemeroy
        compared serum proteins of
        cetaceans against all other
        mammal orders (except
        rabbits). Artiodactyls were
        closest.
Some anatomical properties of living whales
• Whales have streamlined bodies w/ tails flattened into
  horizontal flukes.
• Limbs:
   – Traces of femurs and pelvic girdles are present in some species.
   – Arm bones (humerus, radius, & ulna) shortened; however, fingers 2 & 3
     (& occasionally others) lengthened to support paddle-like swim-fins.
• Nostrils exit through ―blowholes‖ on the top of the head.
   – In almost all species these are displaced high & far back; resulting
     alterations in the structure of the mammalian skull are impressive.
   – Two blowsholes in baleen whales, one in toothed whales
• The skin of adults is hairless, but a thick layer of blubber
  (subcutaneous fat) provides insulation.
• All whales exhibit an extensive suite of anatomical,
  physiological, and behavioral specializations connected with
  aquatic existence and deep diving.
• More whale anatomy:
  – Rear legs are absent.
  – Front legs are modified
    as ―flippers.‖
  – Cervical vertebrae are
    fused.
  – Backbone is modified
    for vertical flexing.
   Size & the physics of swimming
• Most cetaceans cruise at approximately ―brisk
  bicycle‖ speeds; orcas have been clocked at
  55kph.
• Speeds are a function of power-input/drag ratio.
  – Reducing drag (=minimize turbulence/laminar flow):
     • Protrusions eliminated; shape sculpted…
     • Skin evolved to minimize local pressure fluctuations…
  – Increasing ratio:
     • Drag is a function of X-sectional area (a ―squared‖
       quantity).
     • Power is a function of muscle-mass, which is a function of
       body-volume (a ―cubed‖ function).
     • Therefore, get big (and get long)!
     Baleen (―whale-bone‖) whales
• The toothless whales take their name from the baleen with
  which they strain out their food from the H2O. Basic feeding
  strategy is to eat fairly low on the food chain!
• Structure of baleen:
   – Formed in triangular, flat plates, which are composed from strands of
     horny epithelium embedded in a less durable material.
   – At the edges of a baleen plate, the less durable material erodes away
     and leaves a comb-fringe of the epithelial material.
• Mouths of baleen whales:
   – 130-400 baleen plates hang from each side of the whale’s upper jaw.
   – The plates are arranged so that their fringes form a continuous strainer.
• Baleen whale feeding:
   – Whale takes in a huge gulp of H2O.
   – Then the animal closes its mouth (not tightly).
   – As the whale then raises its huge tongue, H2O is forced out through the
     baleen strainer—thereby retaining small food-organisms (see next slide).
   – Some baleen whales skim the surface (slide after next).
   – Gray whale scrapes the bottom & strains the muck (not illustrated).
• A: Open mouth of baleen whale, showing hanging sheets of baleen and
  large tongue.
• B: A triangular sheet of baleen, frayed toward the bottom to form a strainer.
• C: Cross-section of baleen whale’s head. 2 sets of baleen sheets show as
  dark triangles hanging from upper jaws. Tongue is drawn almost entirely
  raised—& would be forcing water out of mouth, through the baleen ―strainer.‖
• D: Reduced skeleton of a whale within the outline of the animal’s body.




              Tongue
Two (of 3) baleen-whale feeding methods:
  straining (left) and skimming (right):
                Biggest baleen whale




• Size: ave 27m; 150,000kg (XX somewhat larger than XY).
• The blue whale’s year:
   – Spend 3-4 months/yr in higher latitudes.
   – As weather cools, blues move equatorially, pregnant XX’s first.
   – Young born near equator; nursed until they have enough blubber to
     withstand polar summer.
   – New mothers & young return ASAP to feeding waters (offspring must
     grow, & XX’s must recover energetic expenses of repro).
   – XX w/o calves mate in tropics; on return to feeding grounds they eat like
     crazy to carry them through 11-mo gestation & subsequent lactation.
   – XY’s—esp. adolescents—leave feeding grounds later than XX’s.
    Toothed whales (Odontoceti)
• This Suborder includes 6 Families with about
  35 genera and 67 Recent species. In contrast
  to baleens, odontocetes eat high on food chain.
• Odontocetes occur in a bewildering array of
  forms–medium, large, and very large.
• Some species are particularly adapted for fresh
  water (in South America and Asia).
• The Suborder’s most interesting adaptations
  include sounds:
  – Narrow-band continuous tones (whistles & squeaks
    used for intraspecific commo).
  – Broad-band clicks used for echolocation.
         Odontocete mysteries:
• Echolocation: How does it work? (Next slide.)
• ―Death Rays‖: Evidence from sperm whales
  suggests that some odontocetes can focus
  sounds very precisely, emitting waves of high
  frequency and extraordinary intensity….
• Geomagnetic navigation. It appears that some
  (many?) odontocetes (and some baleen
  whales?) can orient with respect to the earth’s
  geomagnetic field….
• Neither of these latter 2 suppositions has been
  definitively demonstrated.
                    • Sound is generated by
     Echolocation     movement of air through
                      amplifying nostrils.
                    • Sound bounces off
                      dorsal surface of
                      cranium and is
                      ―focused‖ by melon
                      (complex lipids, ―slow‖
                      center & ―fast‖ shell).
                    • Reception is through
                      thin mandible and
Ganges river          associated fat running
dolphin               from snout to ear.
                    • Some species can
                      pretty much substitute
                      echolocation for sight.
                                     Sperm Whale (Physeter
                                        macrocephalus)




• XY maybe to 30m, mass 45,000-70,000kg.
• XX much smaller (c. 10m & 17,000kg).
• Social organization:
   – XX near-tropical, in groups of 10-40 (+ dependent young).
   – XY worldwide, w/competition for harems.
• Preferred food probably giant squid; also eat fish, octopus,
  crustaceans. Consume 3-4% body mass daily.
• Dolphins (Dephinidae, worldwide) are the most familiar & abundant
  cetaceans. (B.N.D.’s are called “porpoises” in South Carolina!)
• Range in size from person-sized miniatures to killer whales (7m & 4,500kg).
• Evolved in late Miocene, c. 10MYBP).
• Food:
    – Species w/long beaks & many cone-like teeth: fish-eaters.
    – Species w/shorter beaks & larger teeth: squid-eaters (but orcas…).
• Bottlenose dolphins have huge brains.
    – Evidence suggests this is associated w/ hearing & processing of echolocative
      sounds.
    – Individual animals have unique whistles.
• Bottlenoses associate in large groups that fracture into smaller groups of
  definite composition.
Narwhale (above) 4.25m; 1250kg (XY
slightly larger than XX)

    Some other                            Beluga (above): XY 5m,
                                          1600kg; XY: 3.75m, 350kg
    toothed                     B.N.D.
    whales                      (right)

Dall’s porpoise (below): 1.8-   4m
2.1m; 135-220kg                 635kg
        Next Order: Lagomorpha
• Includes two living Families:
  – Ochotonidae (pikas): 1 genus, c. 14 species.
  – Leporidae (rabbits): 8 genera, > 50 species.
• Evolutionary history:
  – Ancient group, probably Cretaceous in origin.
  – Earliest fossils are Paleocene of Mongolia.
  – By Eocene both Families in Eurasia & N. America.
• Basically, lagomorphs are small herbivores able
  to exploit relatively wretched vegetation
  because of unusual fermentation strategies.
           Lagomorpha                    • 2 Families, c. 80
                                           species.
“Lattice-work” rostrum and somewhat
mobile, almost “hinged” cranium
                                         • Most major
                                           landmasses (not
                                           Australia, southern
                                           South America,
                                           Madagascar, or
                                           Antarctica).
                                         • Known from
                                           Paleocene.
                                         • Possibly related to
                                           rodents.
                                         • Small herbivores.
Incisors 2/1      Rodent-like diastoma
Ochotonidae (pikas) 2 genera, 26 sps.
                  • Pikas are round animals,
                    c. 150-200g, resembling
                    fat squirrels w/o tails (or
                    resembling big-eared
                    voles).
                  • Mountains of western
                    North America, + steppes
                    & mountains of Asia.
                  • Live colonially in rock
                    jumbles.
                  • Dry vegetation for ―silage‖
                    & base territory around
                    defense of these hay
                    piles.
                      Rabbits
• Informally split into two subfamilies:
  – Rabbits: altricial young (e.g., cottontails)
  – Hares: precocial young (e.g., jack ―rabbits‖)
• Nutritional strategy:
  – Eat coarse vegetation high in cellulose.
  – Hindgut fermenters w/ high surface/volume ratios.
  – Re-ingestion of caecotrophic feces (next slide).
• Reproductively an extreme r-species (next + 1)
• Social systems (2 basic types):
  – Dispersed, somewhat like forest artiodactyls.
  – Warrens w/ dominance hierarchies (especially
    important among XX’s).
                                              Rabbit digestion
                                              • Rabbits eat a lot!
                                                 – Mass: 6%-8% body mass
                                                 – Calories: 54kcal/kg-day
                                              • Cellulose:
                                                 – Mostly separated out.
1. Food input
                                                 – Even if fermented in
2. Stomach; regular emulsification, etc.           caecum, cellulose is
3. Small intestine; absorption of proteins,        poorly digested (c. 14%).
   starches, sugars….
                                                 – Very rapid throughput!
4. Large intestine; recovery of water, etc.
                                              • Importance of caecum is
5. Caecum; Amino acids (?), water-soluble
   vitamins, fatty acids, etc.                  poorly understood….
6. Hard feces (―rabbit pellets‖).             • Problems w/calcium
7. Caecotrophic pellets; re-ingested.           metabolism….
               Rabbit reproduction
• Gametogenesis:
  – Winter quiescence; reactivation by photoperiod.
  – Males more easily activated.
  – Ova mature in response to FSH (if sufficient food); their
    development is arrested in sub-mature stage.
• Courtship and copulation:
  – Faint heart never won fair rabbit!
  – Feedback through pituitary: LH surge in < 1hour; ovulation
    within 10 hours.
• Pregnancy (28-day gestation):
  – Corpora lutea are initial progesterone-secreting structures.
  – Later, placenta; CL regress; FSH, ova to sub-mature stage
• Recycling:
  – Post-partum copulation
  – If insufficient milk, total resorption in days 8-15.
South Carolina rabbits
            • The most common state-
              wide is cottontail, left.
               – Exploits successional
                 habitats.
               – Populations vary from year to
                 year.
            • The marsh rabbit is a
              coastal-plain species.
               – Eats mostly semi-aquatic
                 vegetation.
            • Swamp rabbit is restricted
              to Pickens, Anderson, &
              Oconee Counties.
               – This is a big rabbit of river
                 bottoms and canebrakes.
                                                  Other rabbits
                                                • I.P.R. is an endangered,
                                                  small cottontail.
Idaho pygmy rabbit   S.E. Asian forest rabbit   • Tropical rabbits of
Jackrabbit           Snowshoe hair                Southeast Asia are poorly
                                                  known.
                                                • Jackrabbits (hares) of
                                                  the American west
                                                  compete with domestic
                                                  livestock.
                                                • The snowshoe hare
                                                  (left) is a large, northern
                                                  animal varying seasonally
                                                  in color. It makes huge
                                                  caloric demands.
   Hyracoidea 3 genera, 6 species
• This Order includes a single living Family, the
  Procaviidae, which has 3 genera and 11-12
  species.
• Formerly widespread, hyraxes are now
  restricted to Africa and a tiny segment of the
  Middle East.
• Extinct varieties included rat-sized and rhino-
  sized animals; living members are rabbit-size.
• Hyraxes are thought to be related to elephants
  and sea cows, part of an Afrotherian radiation
  (next slide) into drier, herbivorous niches….
Hypothesized components of the
    Afrotherian Radiation:
•   Aardvarks (later in this presentation)
•   Elephant shrews (later in this presentation)
•   Golden moles (treated as ―insectivores‖)
•   Tenrecs (treated as ―insectivores‖)
•   A proto-ungulate radiation:
    – Hyraxes (the Order of present consideration)
    – Sea cows (later in this presentation)
    – Elephants (considered as a separate topic)
• Hyraxes were most successful; why have
  they declined so much?
      Hyraxes
• Rock hyraxes are highly
  social animals living in
  groups of 5-50.
• Food is vegetation, often
  heavy in cellulose,
  fermented in the hindgut.
• Perhaps to conserve
  energy, hyraxes have
  labile body
  temperatures.
• ―Group huddles‖ on cold
  mornings help hyraxes
  thermoregulate.
Hyrax digestive system

• Hyraxes might have
  been the first efficient
  mammalian fermenters.
• 2-compartment stomach,
  small intestine, two
  different caeca, and
  joining large intestine all
  have different digestive
  rolls.
• Uh, but different roles
  are not well understood
  by me!
Hyrax technical characters
            • Skull and teeth:
               – Convergence w/rodents:
                  • Ever-growing upper incisors
                  • Dental diastoma
               – Note deep lower jaw

            • Feet (rear illustrated):
               – 3 syndactylus toes w/nails
                 instead of claws
               – Sole evolved for superior
                 traction
               – Foot structure is associated
                 with the Order’s survival
                 and its limits!
                          Sea cows
• Part of Afrotherian radiation, these big, aquatic herbivores have
  oar-like arms, vestigial hindlimbs, & paddle-shaped tails.
• The nostrils are high on the skull, behind the anterior margin of
  the small eyes. The lips are large & flexible. The upper lip has
  numerous vibrissae-like whiskers, but the sea cow body is
  otherwise hairless.
• All living sirenians lack canine teeth.
• Dugongs: XY dugongs have 1 blade-like incisor in each upper
  jaw. Molarform teeth are un-enameled. A dugong’s jaws can
  appear to be covered with horny plates—something like those
  seen in many turtles.
• Manatees: Adult manatees lack incisors as well as canines.
  Their molarform teeth are adapted for grinding massive
  quantities of aquatic vegetation. These teeth are lost from the
  front and replaced in the rear, as with their distant relatives, the
  elephants (but manatees have more teeth).
       Recent Sea-Cow Species
• Manatees:
  – Amazonian manatee. A fresh-water animal
    feeding in floating meadows of aquatic vegetation.
  – West Indian manatee. Mostly salt water entering
    fresh water in N. Am. mostly for warmth. (Slide.)
  – West African manatee. Late Pleistocene re-
    immigrant from New World. Fresh & salt water.
• Dugongs:
  – Dugong. Indian Ocean & South Pacific. (Slide.)
  – Steller’s Sea Cow. Bearing Sea. To 10,000kg
    (largest non-whale). Discovered 1741; extinct
    1768.
             Manatees
• These are large (c. 400kg) New
  World & West African animals.
    – Insulation is not good, so despite
      small S/V ratio, manatees are
      restricted to warm H2O.
• Feeding, & Nutritional physiology:
    –   Diet low in nutrition
    –   Teeth (6-7/quad, horiz. replace.)
    –   Huge digest.-tract (40m long)
    –   Very slow throughput
    –   Very high extractive efficiency
• Groups ephemeral; multiple XY’s
  chase receptive XX’s.
• Manatees make many sounds that
  carry great distances & convey
  social information
• Interbirth interval is c. 3 years;
  social maturity for XY is at 9-10
  years; XX mature more rapidly.
  Lifespan is long.
                         More on manatees

      T. senegalensis?




•   Bones are very heavy (no marrow cavities in longbones or ribs).
•   Shape and position of lungs; breathing efficiency….
•   Bone-weight, CH4, diaphragm, and buoyancy….
•   Brain is relatively small and relatively simple.
•   Low metabolic rate, K-selection, general life strategy.
Dugong
    • Appearance:
         – Dugong: indented tail.
         – (Manatee: paddle-like tail.)
    • Range:
         – East coast of Africa, south
           coast of Asia; South Pacific
           to Australia & Caroline
           Islands.
    • Size: 250cm; 300kg.
    • Feeding:
         – Strong lips for eating sea
           grasses.
    • Other:
         – Large incisors apparently
           used in XY-XY combat.
Macroscelidia (elephant shrews)




              Giant Short-eared


              Checkered
                          Golden-
                          rumped
Elephant shrews
          • Once classified w/
            Insectivora; now called
            members of Afrotheria.
          • Fossils known only from
            Africa (as early as
            Eocene of Tunisia).
          • 4 genera and 15 living
            species.
          • Size:
             – Large mouse (50g) to
               large rat (450g)
          • Food is primarily insects
            (termites & ants in one
            studied species).
    More on
elephant shrews
• Elephant shrews are
  monogamous, with XX & XY
  scent-marking territories &
  defending against same-sex
  conspecifics.
• Gestation is long; twins are
  produced, XY does a little
  child-care, but….
• Pairs maintain trail systems
  (important), with XY doing
  most trail maintenance.
       Tree Shrews (Scandentia)
• The Order has one Family, about 5 genera and
  perhaps 19 living species.
• Range includes much of South & Southeast Asia.
• Classification:
  – Once placed w/primates because of skull features.
  – Now considered sister Order to primates, bats, and
    dermopterans (and rabbits?????????????).
• Social system:
  – Long-term bonds between XY & multiple XX’s.
  – Territories defended against same-sex conspecifics.
  – Mothers deal with their babies about 1 time/2 days, feeding
    w/ large quantities (to 20% body-mass) of high-quality milk
    (10% protein, 26% fat).
Two Treeshrews ( Tupaia tana & Dengrogale
                 minuta)
                     • Three shrews were
                       formerly thought to be
                       largely insectivorous
                       (because of teeth).
                     • Now they are known to
                       consume much fruit.
                     • Rapid pass-through rate
                       (13-29 min!) is like fruit-
                       eating bats– and makes
                       tree shrews important
                       seed dispersers.
        Dermopterans




Protected orbits Multi-cusped canines

• 1 genus, 2sp. of S.E. Asian arboreal leaf eaters.
• 1-1.75kg; h-b 34-42cm; tail 25cm; 70cm wing-span (note tail).
• Hindgut fermenters, so low-energy creatures.
• Crepuscular or nocturnal gliders in forests with broken
  canopies.
• 1 altricial young clings to mother’s underside.
                 •1-1.75kg; h-b 34-
                 42cm; tail 25cm;
                 70cm wing-span (note
                 uropatagium).
                 •Hindgut fermenters,
                 so low-energy
                 creatures.



Colugo
Dermopteran
“Flying lemur”
Cynocephalus
variegatus
The Noble Aardvark

• H-b 100-160cm; mass
  50-100kg!
• Ancestor of artiodactyls?
  Member of Afrotheria?
• Have regular foraging
  routes & exploit termites
  (wet season) and ants
  (dry season) in ways
  reminiscent of giant
  anteaters.
• Dig enormous burrows
  shared by many
  vertebrates.

				
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