Whale Adaptations: The Head
to Main Lesson
on drawing to see labeled enlargement
throat grooves are expanded on this Gray Whale.
Photo Renee Bonner
hangs from the whale's upper jaw and works to strain food out of
gulps of water.
Mouth for Eating Tons of Food
- When the
whale is feeding, 3-5 throat grooves expand to hold vast amounts of
sea water. In the Arctic feeding grounds each summer, an adult gray
whale will probably gulp about a ton of food every day! The whale expands
its throat to hold huge amounts of seawater and food, then compresses
its throat and pushes the water out through the baleen plates in its
- The tongue
can weigh 1000-3000 pounds (up to 1,300 kg). It represents at least
5 percent of the entire surface area of a gray whale's body. A special
adaptation keeps the whale from having hypothermia (losing heat through
its tongue) when its huge mouth is open to frigid Arctic seas for as
many as 20 hours a day; its huge tongue has networks of arteries and
veins that seem to act as heat exchangers that help conserve the whale?s
takes the place of teeth for whales in the suborder Mysticeti.
Baleen is made from a fingernail-like material called keratin. Baleen
whales have a series of 130-180 fringed, overlapping baleen plates,
2 to 10 inches (5-25 cm) long, hanging like curtains from each side
of the upper jaw where teeth might otherwise be found. Like giant combs
or strainers, baleen plates filter water out and trap food inside the
- The huge
tongue is muscular and nimble to help the whale during feeding. In order
to feed off the bottom of the ocean, the whale swims to the bottom,
rolls on its side, and plunges its head a few inches into the muck.
By expanding and contracting its throat grooves and retracting its huge
tongue, the whale creates suction to suck mud and organisms into its
mouth. The whale pushes the mud-food mixture around with its tongue,
then pushes it out through the "curtain" of baleen. The food
stays trapped inside. Then the whale uses its tongue to lick food off
the baleen, much as you might suck peanut butter off the roof of your
mouth, and swallows it. Gray whales also feed upon floating and swimming
organisms, gulping in mouthfuls of nutrient-filled water and filtering
the water through the baleen.
Move and Change to Blowholes
- What used
to be nostrils in landlubbing whale ancestors slowly developed into
one or two blowholes located at the top of a whale?s head. Whales inhale
and exhale air through their blowholes. Because its blowholes are so
high on its head, a gray whale can breathe by barely breaking the surface
of the water. The skin around the blowholes has many specialized nerve
endings that are sensitive to changes as the blowhole breaks the water?s
surface. The whale can inhale and exhale in a fraction of a second.
in a series of valves and plugs keep the blowholes closed when the whale
is underwater. A swimming gray whale's mouth may be full of water, but
it won't miss a breath because the blowholes connect directly to the
blowhole on baby gray whales
Adaptations for Sensing the World around Them
have just a small hole and no external ear on the head. Instead, a gray
whale's jawbone plays a very important role in sound reception and hearing.
- The gray
whale?s most important sense is hearing. The auditory nerve is relatively
larger than in other mammals, and the parts of the brain responsible
for hearing are highly developed.Unlike dolphins and killer whales,
gray whales do not appear to use high-frequency sounds for echo-location.
the eyes are located far back on the head, whales do not have good binocular
vision like humans do. The gray whale must move its entire body to get
a good look at something. It cannot even see something that's just in
front of its nose. The eyes are small, about the size of a baseball.
Although the eye and optic nerve are rather undeveloped in gray whales,
grays seem to have fair eyesight in both water and air. A layer of cells
at the back of the eye acts like a mirror to reflect light back to the
retina over and over again. This is a great help in low light conditions,
such as murky water. The retina also contains many rod cells, which
are sensitive to low light.
- The white
part of the whale?s eyeball is thick and resilient and can take high
pressures without deforming on deep dives.
This! Journaling Questions
The food items they eat are incredibly tiny, but gray whales are very efficient
feeders. Their metabolism is very low so they make efficient use of food
energy, burning far fewer calories per day per pound of body weight than
- How does
this help gray whales in frigid water?
- How does
it help them during their migration? How does it help mother gray whales
when they have young babies?
- If this
adaptation is so useful, why aren't humans adapted to be more efficient