dogs exam 2

canis dirus

dire wolves

de-extinction

gray wolves today (3)

population went down about 95% in North America and Eurasia

population went down 80% world-wide

population overall went down 90%

canis lupus (3)

• less than 1 million years ago

• most went extinct except gray wolves

• through Eurasia and North America (Holarctic radiation)

18th-20th century hunting (3)

• settlers re-encountering wolves and predators in the west

• killing of bison

• introduction of new preys like cattle, sheep, goats, etc.

19th-20th century hunting (3)

• protection against predators

• bounties of predators

  • $5 for mountain lions

  • $3 for wolves

  • $2 for bears

  • $1.5 for lynx

• various hunting tools and traps

Yellowstone in 1872

1st national park in the world

yellowstone in 1914 (2)

wolf extirpation campaign

congress funded predator hunting

yellowstone in 1926

wolf population is threatened

yellowstone in 1940

wolf population is endangered

domestication syndrome traits (9)

• lower fear and aggression hormone levels (cortisol, adrenaline, thyroxine), also known as changes in neural crest cells

• increased sociality

• color variation

• smaller

• shortened limbs and faces

• floppy ears

• smaller brain

• earlier reproduction

• less sexual dimorphism

changes in endocrine (hormone) system results in what

domestication syndrome

endocrine system

collection of glands that secrete hormones directly into circulatory system to be carried towards target organs

hormones (2)

regulatory chemicals produced by glands and transported in tissue fluids to stimulate specific cells or tissues into action

regulates metabolism, growth and development, etc

thyroxine hormone (4)

secreted by thyroid

regulates metabolism

shapes how cells use ATP, impacting metabolic rates

works with adrenaline

hypothalamus pituitary-adrenal axis (HPA) (5)

cortisol and adrenaline

controls reactions to stress

• mid-brain: motor coordination and arousal

• pituitary: growth, development and function of glands

• adrenal glands: produces adrenaline and stress hormones

neural crest cells (4)

HPA develops from this

stem cells that migrate to different parts of the body

formed near developing spinal cord of vertebrate embryos

yields to pigment, cartilage, skull, jaws, teeth etc.

domestication process (2 steps)

1. self-domestication (self-sorting): wolves sought out humans for food

   1. proto-dog (anthropogenic): humans selecting wolves that were less aggressive

   2. coevolution: wolves get food, humans get protection and assistance in hunting

2. followed by humans selecting traits which led to breeds (artificial selection)

pat shipman

modern humans’ migrations to Europe and Asia

neanderthals vs humans

• humans had a larger brain

• better resources

• help from wolves

more thyroxine/cortisol/adrenaline hormones

less bold, more fight or flight

less thyroxine/cortisol/adrenaline hormones

more bold, less fight or flight

farm fox experiment (3) and the 4 classes

domestication experiment in Russia by Professor Belyaev

believed that domestication was from selection for tame behavior

selectively bred fox for tameness

assigned foxes to reaction classes

• class 3: flee, bite

• class 2: not friendly

• class 1: friendly

• elite: seeks out humans

dog breed types (4)

hunting

guard

sheep

lap

500BC-500AD dogs

selective breeding, early training, morphology and behavior

ex. sheep dogs have white fur

ex. guard dogs should be black to appear threatening

ex. sighthound hunting dogs and mastiff guard dogs

1200s-1500s (3)

hunting became a status of power in Western Europe

laws of hunting (venery)

flux of hounds

ex. deerhound, wolfhound, boarhound, elkhound, etc.

american kennel club stats

around 190 recognized breeds

breed gropus (7)

• sporting

• hounds

• terriers

• working

• herding

• toy

• non-sporting

dogs in human health and medicine (4)

• assistance for visually disabled

• seizure alert

• detection of cancers

• PTSD

dogs in warfare and military (7)

• scouts

• sentries

• trackers

• patrol

• message delivers

• detecting mines

• finding victims

behavioral (dog perception)

needs to know preceptual world of a species to fully understand its behaviors

evolutionary (dog perception)

sensory and perceptual systems under intense natural selection pressure

dog’s sensory systems (6)

• visual (sight)

• auditory (hearing)

• olfaction (smell)

• vestibular (balance/orientation)

• gustatory (taste)

• somatic sensation (tactile/touch)

dog visual sensory system (5)

• better night vision

• detects motion

• greater visual range

• cannot see reds/greens

• cannot detect patterns and detail

  • slightly less binocular vision range

visual acuity (2)

ganglion cell connects to photoreceptors (converts photons into signals) to optic nerve

• cones: perceive color through a color spectrum

• rods: lightness

visual streak: acuity in a narrow range on horizontal plane

human 4:1 vs dog 1:1

temporal resolution

rapidly electrical signals are moved down optic nerve to occipital (connected to eyes) part of brain

binocular (3D) stereoscopic vision (2) and its relation to prey and predator

binocular - position of eyes influences overlap of visual field which facilitates depth perception

stereoscopy - visual signals going to the brain

prey: more peripheral vision

predator: more depth perception

monochromats

1 cone photoreceptor

some mammals

dichromatic

2 cones photoreceptors

most mammals including dogs

trichromatic

3 cones photoreceptors

primates and humans

tetrachromacy

4 cones photoreceptors

most animals including fish, birds, reptiles

tapetum lucidum vision

layer of specialized, iridescent cells behind retina that reflect light back into photoreceptors

dog olfaction sensory system and its 2 methods

detect odor molecules by 2 ways..

• olfactory epithelium

• vomeronasal organ

olfactory epithelium smell (2)

odor molecules detected by chemoreceptor cells made of epithelium tissue lining the nasal cavity

chemical info transmitted to olfactory nerve axons in the brain

vomeronasal organ smell (4)

at the base of nasal aperture

in most mammals

detects pheromones and used in reproductive behavior

bonding to puppy litter

domestication influences communication (3)

• wolves are not as skillful at responding to human cues

• dogs’ skill cannot be explained by learning during growth (a genetic component)

• out-perform wolves and other species like chimpanzees (pan troglodytes)

human-dog communication (2) with functional magnetic resonance imaging (fMRI)

evolutionary change in dogs and humans

coevolution: each of the 2 species impact the evolution of each other through signaling and communication

oxytocin and gaze reward loop (5)

helped coevolved in humans and dogs and facilitates bonding

• oxytocin hormones

• face reading

• hand gestures and interpretation

• response to emotional valence of voice and interpretation

• dog interactions and emotions of each other

olfactions (smell) and behavior associative learning

linking between smell and behavior

• odor: olfactory

• emotion: amygdala

• memory: hippocampus