Chapter 7 Thinking and Intelligence 255prewired and automatic (Wynne, 2004). The
assassin bug of South America catches termites
by gluing nest material on its back as camouflage,
but it is hard to imagine how the bug’s tiny dab of
brain tissue could enable it to plan this strategy
consciously. Yet explanations of animal behavior
that leave out any sort of consciousness at all and
that attribute animals’ actions entirely to instinct
do not seem to account for some of the amazing
things that animals can do.
Like the otter that uses a stone to crack
mussel shells, many animals use objects in the
natural environment as rudimentary tools, and
some nonhuman primates learn this skill from
others of their species. Chimpanzee mothers
occasionally show their young how to use stones
to open hard nuts (Boesch, 1991). Orangutans in
one Sumatran swamp have learned to hold sticks
in their mouths to pry insects from holes in tree
trunks and to get seeds out of cracks in a bulb-
like fruit, whereas nearby groups of orangutans
use only brute force to get to the delicacies (van
Schaik, 2006). Even some nonprimates may have
the capacity to learn to use tools, although the
evidence remains controversial among etholo-
gists. Female bottlenose dolphins off the coast
of Australia attach sea sponges to their beaks
while hunting for food, which protects them
from sharp coral and stinging stonefish, and they
seem to have acquired this unusual skill from
their mothers (Krützen et al., 2005). Is this yet
another case of mothers telling their daughters
what to wear?
In the laboratory, nonhuman primates have
accomplished even more surprising things. For
example, chimpanzees have demonstrated a rudi-
mentary sense of number. In one study, chimps
compared two pairs of food wells containing choc-
olate chips. One pair might contain, say, 5 chips
and 3 chips, the other 4 chips and 3 chips. AllowedYou are about to learn...
• whether animals can think.
• whether some animal species can master
aspects of human language.
animal Minds
A green heron swipes some bread from a pic-
nicker’s table and scatters the crumbs on a
nearby stream. When a minnow rises to the bait,
the heron strikes, swallowing its prey before you
can say “dinner’s ready.” A sea otter, floating
calmly on its back, bangs a mussel shell against
a stone that is resting on its stomach. When the
shell cracks apart, the otter devours the tasty
morsel inside, tucks the stone under its flipper,
and dives for another shell, which it will open
in the same way. Incidents such as these and
scores of others have convinced some biologists,
psychologists, and ethologists that we are not
the only animals with cognitive abilities—that
“dumb beasts” are not so dumb after all. But
how smart are they?
Animal Intelligence LO 7.19
For decades, any scientist who claimed that ani-
mals could think was likely to be ignored or
laughed at. Today the study of animal intelligence
is booming, especially in the interdisciplinary field
of cognitive ethology. (Ethology is the study of ani-
mal behavior, especially in natural environments.)
Cognitive ethologists argue that some animals can
anticipate future events, make plans, and coordi-
nate their activities with those of their comrades
(Griffin, 2001).
When we think about animal cognition, we
must be careful, because even complex behavior
that appears to be purposeful can be genetically
How smart is this otter?
Dodger, a 2-year-old dolphin in Shark Bay, Australia,
carries a sea sponge on her sensitive beak as protec-
tion against stinging creatures and sharp coral. Dolphin
“sponge moms” apparently teach the behavior to their
daughters.