Module 2: Sensory Abilities of the Dog-Sight & Hearing

Question 1

surrounds and protects the eyeball, uniting with the cornea at the front

Answer 1

sclera

Question 2

transparent but tough, and nearly invisible when viewed straight on

Answer 2

cornea

Question 3

muscle under control of the autonomic nervous system, responds automatically to the level of light by opening or closing to regulate the amount of light entering the eye, what you see as the colored portion of the eye. It attaches to the suspensory ligaments through the ciliary body.

Answer 3

iris

Question 4

What color are dogs eyes usually?

Answer 4

brown, hazel/amber, or blue.

Question 5

improves low-light vision even further

Answer 5

tapetum lucidum

Question 6

a nonreflective layer of dark pigmented cells, this arrangement enhances contrast in both visual planes

Answer 6

tapetum nigrum

Question 7

oval section that lies on the retina above the optic nerve, with its length along the horizontal plane, is thought to assist the dog both in use of peripheral vision and the quick scanning of the horizon for items of interest

Answer 7

visual streak

Question 8

a third eyelid, when the upper eyelid closes, it sweeps across the eye, clearing away any foreign bodies

Answer 8

the haw or nictitating membrane.

Question 9

Dogs can’t differentiate the colors _____ from ______ from ___

Answer 9

green, orange, red

Question 10

the area seen when the eyes are focused ahead, including what we call peripheral vision.

Answer 10

Field of view

Question 11

estimates of the canine field of view generally range from ___ to ___ degrees.

Answer 11

240 to 250

Question 12

_________ refers to using two eyes, while _________ refers to using one eye.

Answer 12

Binocular, monocular

Question 13

(short-nosed) breeds have their eyes placed on a flatter front of the face, more closely resembling humans

Answer 13

brachycephalic

Question 14

(long-nosed) breeds have more slanting faces and thus have eyes placed both more to the sides and angled more obliquely

Answer 14

dolicocephalic

Question 15

What problems should always be ruled out before working on behavioral issues?

Answer 15

Physical problems

Question 16

if a dog suddenly squints and becomes teary-eyed, suspect an injury to the ______.

Answer 16

cornea

Question 17

a dog’s visual overlap— where the fields of the eyes are shared—is a quite narrow __ to __ degrees compared to humans’ 140 degrees

Answer 17

30 to 60

Question 18

The ear flap of a dog

Answer 18

leather or pinna.

Question 19

The auditory ossicles are known individually as

Answer 19

the hammer (malleus), anvil (incus), and stirrup (stapes).

Question 20

Experts cite a dog’s hearing ability to be in the upper limits of _____ to even ______ hertz.

Answer 20

35,000 to 100,000

Question 21

a canine’s hearing is greatly diminished if one or both of the ears are _______. A dog’s ears should be checked by a veterinarian on a regular basis.

Answer 21

plugged

Question 22

_____ ears stand straight up as opposed to ____ ears, which flop down.

Answer 22

prick, drop

Question 23

All puppies are born ____, but the ears “open” in about __ to __ days

Answer 23

deaf, 10-14 days

Question 24

Deafness is a problem more often related to breeds with which color coats?

Answer 24

white

Question 25

What use does the dog’s ear flap serve?

Answer 25

focuses and collects sound.