Graphics Reference
In-Depth Information
nerve is positioned behind the retina. Cuttlefish
can camouflage by intensity of their color. They
have leucophores (the light reflectors) that help
match the blue-green spectrum of their deep-sea
environment.
Discussion of camouflage as an ability of
pretending to be something else can be found in
Chapter 7, Pretenders and Misleaders in Product
Design.
was sounded, again with the underground prairie
dogs emerging to watch (Slobodchikoff, 2002).
Humans hear sounds of about 12 Hz to 20 kHz.
With their hearing superior to human hearing, with
a range 40 to 60 kHz (dog whistles are set at about
44 kHz), dogs can convey a lot of information and
emotions through their barking. Also bats have
sensitive hearing, between 20 and 150 kHz; they
use it for navigation and echolocation for locating
and tracking their prey. Mice hear sounds of about
1 kHz to 70 kHz. They communicate using high
frequency noises partially inaudible by humans.
Marmots and ground squirrels, groundhogs, squir-
rels, and prairie dogs all are highly social; they
whistle when alarmed to warn others. Chameleons
can sound frequencies in the range 200 to 600 Hz.
Communication through Pitch
Birds communicate by sounds but they try to
avoid being heard by predators. For this reason,
a bird may emit a very high-pitched and a very
short sound, which its mate but not its predator
can hear. Some species display ability to learn
songs. Vocal learning is considered a substrate
for human language. This trait has been found
in three groups of mammals (humans, bats, and
cetaceans - dolphins) and three groups of birds
(parrots, hummingbirds, and songbirds). Vocal
learners gain vocalization through imitation, while
auditory learners do that by making associations
(Jarvis, 2004). Perfect pitch perception is present
in many members of animal kingdom. According
to Slobodchikoff (2002), prairie dogs have highly
developed cognitive abilities; they use vocal com-
munication to describe any potential threat, send
information about what the predator is, how big
it is, and how fast it is approaching. As described
by the author, alarm response behavior varies ac-
cording to the type of predator announced. If the
alarm indicates a hawk diving toward the colony,
all the prairie dogs dive into their holes, while
those outside the flight path stand and watch. If
the alarm is for a human, all members rush inside
the burrows. For coyotes, the prairie dogs move
to the entrance of a burrow and stand outside the
entrance, observing the coyote, while those prairie
dogs that were inside the burrows will come out
to stand and watch also. For domestic dogs, the
prairie dogs stand where they were when the alarm
Other Defense Systems
Leukocytes, white blood cells are involved in
defending an organism against infection. They
evolve from a hematopoietic stem cell produced
in bone marrow. The number of leukocytes in
blood is an indicator of a disease. Immunology - a
branch of biomedical science study the immune
system that protects an organism. It is present in
all organisms: phagocytosis is present in single-
celled organisms, production of the antimicrobial
peptides in arthropods, and the lymphatic system
has developed of in vertebrates; it uses both ways
of protecting an organism, phagocytosis and pro-
duction of immunoactive substances.
The social grouping animals develop many
kinds of the collective defense systems, for exam-
ple by keeping their females and youngsters inside
a herd. Animal communication in associations of
animals goes often through pheromones - secreted
or excreted chemical factors that trigger a social
response in members of the same species. There
are alarm pheromones, food trail pheromones, sex
pheromones, and other types that affect behavior
or physiology of a plant, an insect, a reptile, or
a mammal.
