Dogs: The Sensory Perspective

bijoufriesAI and Robotics

Oct 19, 2013 (3 years and 9 months ago)

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Andrew Costello

John Costello

Tom
Eastaway

Niamh

McLafferty

Sai

Chandra
Padmanabuni

Fan Zhang

Li
Zhogyuan

Tim Zimmermann

Dogs: The Sensory Perspective

Dog Perception


Sensory
-

Senses


Now we could spend a whole semester just
looking at the senses, they are very rich and
detailed.

Dogs: Visual Perception

Dogs: Visual Perception


C
an pick out two colours:


Blue/Violet


Yellow


C
an differentiate among shades of grey


Unable to distinguish green, yellow, orange
and red



Dogs: Visual Perception



Dogs: Visual Perception



Dog

Human

Distinguishing features of a dog eye (1)


The
ora

serrata

is the serrated junction
between the
retina

and the
ciliary

body
. This
junction marks the transition from the simple
non
-
photosensitive area of the retina to the
complex, multi
-
layered photosensitive region.
In animals in which the region does not have
a serrated appearance, it is called the
ora

ciliaris

retinae
.

Distinguishing
features
of a dog eye
(2)


The Nictitating Membrane (Third Eyelid
):


Protection of the surface of the eye because
dogs use their head more actively than
humans


Aspects of Canine Vision


G
reater divergence of the eye axis than
humans, enabling them to rotate their pupils
farther in any direction


V
isual
acuity is poor
their
visual discrimination
for moving objects is very high; dogs have
been shown to be able to discriminate between
humans at
a range of between 800 and 900 m,
however this range decreases to 500
-
600 m if
the object is stationary
.


Have good night vision: Canine’s biggest
advantage



Seeing Eye Dogs


Most dogs have 20/75 eyesight


Seeing eye dogs are bred for desirable
qualities such as eyesight and intelligence


Certain breeds, such as Labradors, may
have closer to 20/20 vision and a suitable
temperament for blind people


Eye Problems


Cherry Eye:

Swelling the nictitating membrane
(third eyelid)


Entropion
:

turning
in of the edges of the eyelid
(usually the lower eyelid) so that the lashes rub
against the eye surface.


Ectopic Cilia:

Abnormal eyelash growth,
relatively common in dogs


Stinky Eyes:
Excessive tearing and drainage
around the eyes may have a foul
odor

from the
discharge collecting on the hair and skin

Dogs: Auditory Perception

Dogs Hearing


The main organ of hearing is the ear.

Dogs Hearing


Differences between dogs ears and human’s.


Dogs ears are controlled by at least 18 muscles, this allows
the ears to tilt and
rotate. Dogs erect ears amplify incoming
sounds, therefore dogs with erect ears can hear better than
dogs with floppy ears. Also the ability to swivel their ears
helps their hearing.


Dogs ears are an important for balance.


Differing form humans high pitched sounds can be
uncomfortable or even painful.


Some dogs hearing will deteriorate as getting older,
similarly to humans.


Dogs Hearing


Dogs frequency levels


Dogs can hear higher frequencies that humans,
for example they could hear the pre
-
stage of an
earthquake with ultrasonic shockwaves over
20kHz, higher than what a human could hear.


A dogs frequency range is typically considered to
be between 40Hz and 65,000Hz.


Frequencies higher than audio are referred to as
ultrasonic, while frequencies below audio are
referred to as infrasonic.

Dogs Hearing


Dogs ‘loudness’ tolerance


An important notion when considering hearing is
“Loudness”, which is a quality of sound that is
primarily a psychological interpretation of the
physical signal strength of a sound (amplitude).


The loudness that dogs are capable of being
heard are typically 10dB and 150dB.

Hearing Threshold

Term

Decibels

Long term

85dB

Short term

120dB

There is a problem in the research into what a
dogs hearing threshold as we do not know what
they can hear. The following are just assumptions
made.

Dogs Hearing


The loudness tolerance depends on the frequency
and vice versa.


Humans hear frequencies between about 20
cycles/sec to 20,000 cycles/sec at
130db
(very loud).
This shrinks to a range of about 700 cycles/sec to
6000 cycles/sec at
0db, we can assume dogs have a
dynamic range of loudness.


In conclusion,
Measurements of physiological
responses to sound (or light) are very difficult and
complicated to quantify.

Dogs: Olfactory Perception

Anatomy of the nose

.

Anatomy of the nose


The nasal cavity is essentially a tube
with a wall established by several
bones
of the skull
. The borders of the nasal
cavity are as follows:


Caudal
: The
cribrifrom

plate of the
ethmoid

bone
.


Ventral
: Continuous with the
nasopharynx
.


Dorsal
: The maxilla and the palatine
processes of the
incisive bone
.


Rostral
: The
median septum is a
continuation of the
ethmoid

bone
. The
median septum is made up of
hyaline
cartilage
, and divides the nasal cavity
into left and right halves.

Dogs
versus
Humans


A dog interprets the world predominantly by
smell, whereas a human interprets it by sight



While a dog's brain is only one
-
tenth the size
of a human brain, the part that controls smell
is 40 times larger than in humans.

Dogs
versus
Humans


Dog’s sense of smell is about 1,000 to
10,000,000 times more sensitive than a
human’s (depending on the breed).



A human has about 5 million scent glands,
compared to a dog, who has anywhere from
125 million to 300 million (depending on the
breed).


Dog receptors
versus
Human

What is
Olfaction?


Olfaction, the act or process of smelling, is a
dog’s primary special sense
.



Olfactory nerves that ultimately connect with
the highly developed olfactory lobe in the
dog’s brain.


Why
is a dog’s nose moist?


A dog’s nose is normally cool and moist. The
moisture secreted by mucous glands in the
nasal cavity captures and dissolves
molecules in the air and brings them into
contact with the specialized olfactory
epithelium inside the nose.

Other uses for the Dogs noses


Olfactory receptor cells in
the
vomeronasal

organ
also send impulses to the
region of the
hypothalamus associated
with sexual and social
behaviors.

Dogs smell is vital for the Dog !

& the lighter side !!

Dogs: Gustative Perception

Taste Buds in Dogs

Animal

Taste Buds

Human

9000


good sense of taste

Dog

1700


stronger reliance on smell than taste

Cat

470


very weak sense of taste


Most of a dog’s taste buds are on the tip of its tongue


Some at back of tongue, some on palate (soft part of
roof of mouth)

Reliance on Smell for Food


Dogs wolf down nice
-
smelling foods


Dogs eat foods with weak smells more slowly


Link between taste and smell (similar link exists in
humans)


Even if it smells bad,


they don’t care >>>>>>>>>

A Salt on the Senses


Humans seek out salt


viz. salty snacks such as
crisps


Dogs get enough sodium from meat


Less developed salt receptors

Sweet Doggie


Omnivores (only ~80% meat in diet)


Dogs’ sweet taste is for a chemical called
furaneol

(found in tomatoes and other fruit)


In the wild dogs frequently supplement diet
with fruit and berries

Water


Tips of tongues specifically tuned to taste
water


This part of tongue used to scoop water up


Shared with other carnivores, but not with
humans


Especially sensitive after eating salty or
sugary foods

The Bitter End


Dislike bitter taste


Deterrent sprays to prevent chewing furniture