Marine Mammology Midterm Muddles

Is it a muddle or a riddle?

Closest living relative to marine mammals

hippos

closest relative to cetaceons

Indohynus, dense bones, evolved early eocene

cetaceon evolution

fatty pad lower jaw, reduction semicircular canals, flexible tail

Archaeocetes examples

Pakicetidae, Ambulocetidae, Basilosaurus, Dorudon

Pakicetidae features

south asia, first cetaceon, ambush predators

Ambulocetus

precursor to fat pad, found near shore

Basilosaurus

first fully aquatic group, didnt echolocate or filter,

Dorudon

most similar to cetaceons

Pinniped evolution

Enaliarctos, Puijila

Enaliarctos

early pinniped, sexually dimorphic, used both flippers for swimming, fully aquatic

which pinnipeds use which flippers for swimming

sea lions and fur forelimbs, true seals hindlimbs, walruses both

Puijila

closest known pinniped relative, similar to otter

sirenia evolution

closest relative elephants, heavy skeletons act as weight

desmostyla

only known extinct order marine mammals,

what are the advantages to being warm blooded in the ocean

can swim fast for long periods, large brain,

what are the dosadvantages to being warm blooded in the ocean

cannot be small, insulation, energy,

3 functions blubber

insulation, energy, floatation

osmoregulation

specialized kidney for salts

sirenian vibrissae

2 types, flexible outer before reached by the stiffer once manipulated

mysticetes vibrissae location

chin for hydrodynamics, blowhole for below surface

Extra senses in dolophins

electrosense, and potentially magnetosense

Mysticetes smell

have olfactory bulb, different from other cetaceons which pick up chelical cues with tounge

how do whales avoid the bends

alveolar collapse

where can oxygen be stored in marine mammals?

blood, muscles, lungs

Types of oxygen storing cells

hemoglobin and myoglobin (higher affinity)

what factors that allow for more oxygen in body are present in diving marine mammals

O2/ml blood, total volume blood

where are excess RBC’s stored in diving cetaceons

spleen, thickens blood which is more difficult on the heart

dive response

reduces blood to peripheral tissues, cardiac output, and bradycardia

Bradycardia

drop in heart rate

aerobic dive limit

maximum limit of dives that doesn’t depend on anaerobic metabolism

what is baleen made of

keratin

whats the name of the white skin on the right whale

callosities

types of whale feeding

lunge, filter, sediment, trap (humpback)

in which types of mysticetes is the baleen smallest

lunge, bowhead has massive baleen

Balaenidae feeding strategy

skim feeders

mysticete reproduction

reproduce south, every 2 years, lactation 6 months, calfs grow rapidly

odontocete reproduction

variable timing, lactate 1+ year

cryptic female choice

allows females to decide which male has their child, harbor porpoises

multiple matings strategy

ensures insemination, confuses parenthood, female choice

pinniped life history calculations

counting rings in canines

phocid breeding

reverse sexual dimorphism, breed in water, little parental investment

embryonic dipause

delays the beginning of an embryo

sirenian reproduction

1 yr nursing, calf learns to find food and freshwater

most stable vs least stable group formation

matrilines vs fission fusion

what type of groups do mysticetes form?

aggregations

Corky

captive orca, played songs of her family

usage of genetics in cetaceon biol

can tell group relatedness

conservation non-lethal issues

stress changing epigenetics, ex orcas

what can stress affect in whales

reproduction, size and growth, reduced perceptive ability

raight whale genetic issues

mortality inbred fetuses

most endangered pinniped in the world

monk seal

Types. ofPAM

dipped hydrophones, towed, bottom mounted, autonomous gliders,

why is pinnipeds voclas so difficult

varied calls and on seafloor so a lot of sound

difference in walrus protection status

least concern in pacific, near threatened atlantic

walrus features

40, maturity 10, matralineal

walrus radiation

left pacific to atlantic then recolonized pacific

walrus human interactions historical

hunted to local extinction 1700s

How to measure genetics of historical walrus’

bone shavings

why is a tusk shorter on one side of the walrus

they have a preferential feeding side

what is distinctive of the maritime walrus

physically and genetically distinctive, more robust, appears to have been on a different evolutionary path

natural history collection functions

show environmental change, references,

seismic blasting

towing an array of airguns to read ocean bottom

vaquita

species caught to near extinction in fishery for totoaba

how are porpoises told to avoid nets

Porposie alert net work, pearl nets

types of boat strike whale

blunt or acute (propellor cuts)

whale watching regulation

100 m distance, leap frogging, reduction viewing vessels,

modern whaling and hunting

some nations (norway, iceland, japan) still whale, and indigenous groups, also seal hunts

which species exibit trap feeding

balenidae, humpback whale

what happens to the pelvis during evolution of marine mammals

detaches from vertebare