:32:00
that is hostile
to air-breathing mammals
:32:04
in the dark of night
:32:06
dolphins need to
know what's out there
:32:21
using their echolocation
:32:22
dolphins can detect the size
:32:24
shape- even the
density of an object
:32:27
but it's only
good for a hundred yards
:32:30
or so and is
highly directional
:32:32
detecting nothing
from behind
:32:44
it's so accurate
they can clearly
:32:46
distinguish between
different species of fish
:33:17
even in daylight
visibility is limited underwater
:33:21
but using sonar can
be risky because the
:33:24
tell-tale clicks may reveal
your presence to predators
:33:29
so dolphins rely more on
their excellent hearing
:33:33
the best defense is to stay together
keep silent - and listen
:33:49
success in hunting is knowing
when to use your sonar
:33:53
and when to turn it off