Answers From The Whale Expert
Special thanks to Anne Smrcina From Stellwagen Bank National Marine Sanctuary for providing her time and expertise in responding to your questions.
Here are whale expert Anne Smrcina's responses to your questions!
Largo High School
Q: Why are they called whales?
A: According to my dictionary, the word whale probably originates from the Old English "hwal" or the Old High German "hwal," or even the Latin "squalus" meaning sea fish. The word "cetacean" comes from the Latin "cetus" menaing whale, and which is probably derived from the Greek "ketos." The Greek philosopher Aristotle was the first person (at least as far as we know) to realize that whales were not fish and that they were mammals that breathed air and had live young.
Q: How come they don't have teeth, but bristles?
A: Some whales do have teeth. It seems that the earliest ancestral whales evolved from land animals. These animals had different types of teeth -- sharp cone-shaped teeth in front for catching and holding, and blade-like back teeth for cutting up the food (heterodonts). As these whales evolved their tooth-pattern changed too. Today, most toothed whales only have one kind of tooth (a pointed tooth for catching and holding -- the prey is usually swallowed whole). This type of whale is called a homodont ("same tooth"). Scientists are not sure if toothed whales and baleen (bristle) whales evolved from the same ancestral line or if they arose from different sources. This split might have happened some 30 million years ago (that's when ancestral baleen whales first appeared). But the feeding adaptations allow these two different types of whales to concentrate on different types of prey. Usually, toothed whales prey on larger fish and baleen whales prey on copepods, krill, other small crustaceans and/or small schooling fish (although some small whales also prey on small schooling fish too).
Q: How do they get to be so big in size?
A: Whales get so large because the ocean has provided an environment that can support that great size. You may have noticed that if you go swimming, you can pick up large items in the water that you couldn't possibly move on land (if your Mom or Dad floats in the water it is really easy to push them around). As the whales evolved they mastered an environment that could provide lots of food and could support large sizes and weights without requiring heavy bones. As you know, on land the only comparable sizes were in dinosaurs and they had very large and heavy bones. Elephants are a lot smaller than the great whales and they have great big bones. There were very few predators on these large whales so they could flourish in this watery world. When humans entered the marine world, whale numbers began to drop precipitously (although natural factors may also have affected whale survival such as natural warming and cooling cycles).
Q: Do the young need a special habitat or temperatures in order to survive?
A: The young of many whale species, including humpbacks and right whales, probably need a somewhat sheltered environment to allow them to be born safely, to nurse and to keep in close contact with their mothers. These whales give birth in warmer waters than that found in their feeding grounds, which probably helps the young too since they have much thinner layers of blubber than the adults. Intensive nursing on rich milk (about 40% fat compared to human milk at 1.5% and cow milk at 4%) allows the baby whale to increase its insulating layer of fat quite quickly. For many adult whales, keeping cool in the summer may be more of a problem than staying warm in the winter. Flipper and tail waving may be a means of releasing heat from those extremities (which have thinner layers of blubber than the rest of the body).
Q: Does the hump serve any purpose to the humpback whale?
A: The humpback whale has a slight "hump" at the front edge of the dorsal fin but it doesn't seem to serve any major function. The pronounced rounding or arching of the humpback's back as it dives may be more significant in terms of its name than the actual "hump." Humpbacks and right whales arch their backs and raise their flukes as they dive, unlike the sleek finbacks. This arching and tail raising may aid them in getting their fatter bodies moving downward as they dive.
Q: Why do only 30% of gray whale calves survive in the lagoons of Baja, California?
A: Since we have no gray whales here in the Stellwagen Bank Sanctuary, I had to consult my counterparts on the west coast at the Channel Islands, Monterey Bay and Gulf of the Farallones National Marine Sanctuaries. No one there could confirm that statistic of 30%, although they did say that quite a few gray whales do die in that first year of life (the number may be over 50%). During the first year of life, and in fact during the first few months, any genetic abnormality will be expressed and may lead to death. Weaknesses in the baby or the mother (sickness/not enough milk) or separation of mother and child may also lead to mortality of the infant. Young whales are also susceptible to attack by orcas or sharks. If the whale makes it through its first year, it has a good chance of making it to adulthood.
Phillis Wheatley Middle School
Q: Why do baleen whales have 2 nostrils and toothed whales have one? Is there a scientific reason for the difference?
A: Just as with the answer to the earlier "bristle" question, the answer lies in evolution. Some people believe the baleen (Mysticetes) and toothed (Odontocetes) whales may have come from a common ancester and diverged in their evolutionary paths many millions of years ago. This long time frame would have allowed these different characteristics to appear. Other scientists say that the two suborders are so different, they must have arisen from two different sources.
Q: How is it possible for whales to dive deep in the ocean and not have a problem with water pressure?
A: When humans dive into the oceans depths they ususally use apparatus like scuba gear that continues to provide air into the lungs. As humans get deeper into the water, pressure compresses bubbles of gas in the bloodstream, allowing more oxygen to be absorbed. When the diver returns quickly, the bubbles expand and can block blood vessels causing a condition called "the bends." That's why it's very important that scuba divers follow the recommended dive charts and decompress in stages as they ascend. Whales don't have this problem. The whale is not taking in any additional air as it dives.
They have evolved a way of getting to great depths unaided. They can transport more oxygen across lung membranes during each breath, can carry more oxygen in their blood, and can transfer more oxygen to the myoglobin in their muscles than humans. Under deep dives, whales' lungs actually compress. Air moves into the trachea (windpipe), preventing nitrogen absorption into the blood. The reserves of oxygen in the blood and muscle provide the whale with the oxygen it needs. In addition, the heart rate slows, and less blood flows to the extremities, also lessening oxygen demand.
From: New Jersey
Iselin Middle School
Q: How do you track the humpback whales?
A: Scientists use both satellite and radio tags to track humpback whales. These tags are used for different purposes (see my Challenge Question answer in the May 13th right whale report). In addition, scientists can tract humpback movements by identifying whales through photographs. Photos of whale flukes (each whale has a different pattern on the back of its fluke) are compared against a catalog or all known humpback whales. If the same whale shows up in two different photos from two different places, the scientist can start to get a picture on this particular whale's migratory pattern.
Q: Have scientists been able to interpret the sounds whales send to each other?
A: Scientists have been studying whale sounds for many years, but we still have more questions than answers. The beautiful sounds (often called songs) of the humpback whale are believed to be "sung" by males as part of the courtship ritual. But we can't be sure. Whales have been heard singing up in the feeding grounds too. These songs change over the season (unlike bird songs), with whales adding or deleting some parts of the song. They usually stop singing when they start heading to the summer feeding grounds. During the next breeding season, they start singing the song they left off with at the end of the previous year.
Scientists have also been studying the sounds of other whales. The deep vocalizations of blue whales may be a way of keeping in touch with other blue whales many miles away (the low tones can carry for many miles in the ocean). The same thing may happen with finbacks. Sperm whales use a form of clicking communication that may help them coordinate their movements. Dolphins may have "signature whistles" that are unique to each animal and help to identify it among the pod.
Q: How much food does a whale eat in one day?
A: It is often said that blue whales can eat a single meal of two tons or more of krill. Right whales may be eating up to a ton of food a day and humpbacks are probably consuming 1,500 pounds of sand lance and other small schooling fish. Since right whales are eating tiny copepods, 4,000 of which may fit in a teaspoon, that's a lot of animals. The larger the whale, the more food it needs.
Q: How long can a humpback whale stay under water before coming up for air?
A: Most of the humpbacks in the Stellwagen Bank National Marine Sanctuary stay underwater from 3-7 minutes. That's because the water is relatively shallow and their food is easy to reach. But humpbacks have been known to dive to depths of at least 600 feet and to stay down for as much as 30 minutes. They may be able to reach even greater depths and time underwater.
Q: How many babies can a humpback whale have?
A: Whales have only been seen with a single baby. Logs from whaling ships indicate that a pregnant female was once caught that was carrying two fetuses (and it may be that other whales can do the same). However, the intensive effort needed to nurse and care for a whale calf may prevent a live birth of twins. The fetuses would probably die even before birth. Twins would also be quite weak, and the ocean is a harsh world. It is quite doubtful that either twin would survive. If two were born and did survive the birth process, it is also possible that the mother would reject one in order to have a better chance of keeping the other alive.
Dr. Howard Elementary School
Q: What if, hypotheticly, an upwelling came to the Atlantic Ocean, where would the whales go?
A: There are presently lots of upwelling areas in the Atlantic, and they are all very important to the food web. Whales tend to be found in such areas, because of this productivity. Upwelling means that nutrients are coming to the surface. The nutrients are taken up by phytoplankton, which are eaten by zooplankton. Some whales eat the zooplankton (like right whales, which eat copepods) and some small fish do to. Other whales eat the small fish.
Q: If the U.S got flooded with water again, and the Gray whales swam over to the Atlantic, would they be able to live? Sincerly, Ben Andr'e, Caitlin, Mckenna,Ali
A: It is believed that a population of gray whales once lived in the Atlantic. If the continent flooded and grays moved over to the Atlantic,. they would probably find some food (provided the food, primarily amphipods, survived the flooding). Grays are bottom feeders, staining the bottom sediments for small crustaceans and there are quite a few amphipods along the east coast.
From: New York
Gotham Avenue School
Q: Our fourth grade students at Gotham Avenue School in Elmont, NY have been following the story of JJ, the orphan gray whale rescued by Sea World. This prompted Phylicia Stephenson to ask whether other whales would adopt an orphan calf. Thank you for your most informative reports. Mrs. Michaels
A: This would be an extremely unusual situation. There has been no known case of large whales adopting another whale, although mother-calf humpback pairs are often seen accompanied by other adult whales. In the case of JJ, the radio tag fell off after two days, so the scientists are not quite sure of what is happening with that whale.
Q: April 8, 1998 at Race POint, Provincetown, MA 8:30-10:30 AM We saw two large headed whales feeding at the surface. Constantly at the the top of the water. Slowly plowing thru the water the heads looked like rounded pyramids. No sign of a dorsal fin. No deep diving only shallow dives showing broad tail. The whales changed direction and were making broad circles in the water. As time paased they moved out to deeper water. Do you think these were northern Right Whale? We also saw one definite Finwhale.
A: Yes, that probably was a right whale that you saw along the Provincetown coast. Right whales are known to surface skim feed on copepod patches close to the Massachusetts shore and at Stellwagen Bank. You certainly were lucky. Most people don't get the chance to see these very rare whales (only 300 left in the North Atlantic population).