Difference between revisions of "AY Honors/Marine Mammals/Answer Key/en"

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Dolphins and porpoises are also classified as toothed whales, but since they appear as a separate group in this requirement, they are not listed here.
 
Dolphins and porpoises are also classified as toothed whales, but since they appear as a separate group in this requirement, they are not listed here.
  

Revision as of 20:10, 20 September 2021

Other languages:
Marine Mammals

Skill Level

2

Year

1991

Version

22.12.2024

Approval authority

General Conference

Marine Mammals AY Honor.png
Marine Mammals
Nature
Skill Level
123
Approval authority
General Conference
Year of Introduction
1991
See also


1

Be able to identify three of each of the following and know where each is found. Know at least one by scientific name from each group:



1a

Toothed Whales


Delphinapterus leucas

Delphinapterus leucas

Beluga Whale (Delphinapterus leucas)

Where found: Arctic and sub-arctic oceans around North America, Russia and Greenland.

Description: Adapted to life in the Arctic, it has a number of anatomical and physiological characteristics that differentiate it from other cetaceans. The unmistakable all-white colour, absence of a dorsal fin, and the distinctive protuberance at the front of its head which houses an echolocation organ called the melon. The beluga’s body size is between that of a dolphin’s and a true whale’s, with males growing up to 5.5 m (18 ft) long and weighing up to 1,600 kg (3,500 lb). This whale has a stocky body; it has the greatest percentage of blubber. Its sense of hearing is highly developed and it possesses echolocation, which allows it to move about and find blowholes under sheet ice. Belugas form groups of up to 10 animals on average, although during the summer months, they can gather in the hundreds or even thousands in estuaries and shallow coastal areas. They are slow swimmers, but they can dive down to 700 m (2,300 ft) below the surface. They are opportunistic feeders and their diets vary according to their locations and the season. They mainly eat fish, crustaceans and other deep-sea invertebrates. Worldwide population is thought be around 150,000 individuals. They are migratory and the majority of groups spend the winter around the arctic ice cap; but when the sea ice melts in summer, they move to warmer river estuaries and coastal areas. Belugas are one of the cetaceans most commonly kept in captivity in aquaria and wildlife parks in North America, Europe and Asia where they are popular with the public due to their colour and expressivity. Wilma the Beluga Whale

Monodon monoceros

Monodon monoceros

Narwhal (Monodon monoceros)

Where found: Arctic and sub-arctic oceans around North America, Russia and Greenland.

Description: Adapted to life in the Arctic, Narwhale Nat Geo. These small whales have a long tusk (actually an elongated left canine tooth) protruding from the mouth. They eat fish which they hunt beneath the pack ice of arctic waters. Thy do not have a dorsal fin as most whales and dolphins do. Narwhals range from 4 to 5.5 meters (13-18 feet) in length.

Physeter macrocephalus

Physeter macrocephalus

Sperm Whale (Physeter macrocephalus)

Where found: The sperm whale can be found anywhere in the open ocean.

Description: Largest of the toothed whales and largest toothed predator in the world. The Sperm Whale breaks all kinds of records! Mature males may reach 20.5 metres (67 ft) and 57,000 kilograms (males much larger than females). It is the loudest of any animal, second deepest diving mammal with dives of up to 90 minutes, largest brain (five times heavier than a human brain), 116 kg (255 lbs) heart, longest intestinal system (exceeding 300 m in larger specimens) and other mind blowing measurements. The sperm whale's distinctive shape comes from its very large, block-shaped head, which can be one-quarter to one-third of the animal's length. The S-shaped blowhole is located very close to the front of the head and shifted to the whale's left, giving a distinctive bushy, forward-angled spray. Primary food is squid and they can live for more than 60 years. The sperm whale's flukes are triangular and very thick. Proportionally, they are larger than that of any other cetacean, and are very flexible. The whale lifts its flukes high out of the water as it begins a feeding dive. It has a series of ridges on the back's caudal third instead of a dorsal fin. The largest ridge was called the 'hump', and can be mistaken for a dorsal fin because of its shape and size. In contrast to the smooth skin of most large whales, its back skin is usually wrinkly and has been likened to a prune by whale-watching enthusiasts. From the early 18th century through the late 20th the species was a prime target of whalers. The head of the whale contains a liquid wax called spermaceti, which was used in lubricants, oil lamps, and candles. Ambergris, a waste product from its digestive system, is still used as a fixative in perfumes. The Sperm Whale is now protected by a whaling moratorium, and is currently listed as vulnerable. Sperm whales have sunk ships, including the real life Moby Dick who sunk the Essex. Jonathan Bird's Blue World: Sperm Whales

Kogia breviceps

Kogia breviceps

Pygmy & Dwarf Sperm Whales (Kogia breviceps)

Where found: Dwarf and Pygmy sperm whales are found throughout the tropical and temperate waters of the Atlantic, Pacific and Indian Oceans. However, they are rarely sighted at sea, so most data come from stranded and captured animals - making a precise range and migration map difficult. The dwarf is more coastal than the pygmy. There is no accurate estimate of number of these whales in the world or good data on conservation status.

Description: The dwarf sperm whale is the smallest species commonly known as a whale. It grows up to 2.7 m (8.9 ft) in length and 250 kilograms (550 lb) in weight. The species makes slow, deliberate movements with little splash or blow and usually lies motionless when at the sea's surface. Consequently it is usually observed only in very calm seas. These two species were not distinguished from each other until 1966 and are difficult to tell apart but the dwarf is slightly smaller and has a larger dorsal fin than the pygmy. The body is mainly bluish gray with a lighter underside with slightly yellow vein-like streaks possibly visible. There is a white false gill behind each eye. The flippers are very short and broad. The top of the snout overhangs the lower jaw, which is small. The whales have long, curved and sharp teeth (0–6 in the upper jaw, between 14 and 26 in the lower). These whales expel a dark reddish substance when frightened or attacked—possibly to put off any predators. They are usually solitary or paired but have occasionally been seen in small groups. All sperm whales have a spermaceti organ in the forehead. The brain of the dwarf sperm whale is roughly half a kilogram in mass.Video of stranded Pygmy Sperm Whale

Berardius

Berardius

Giant Beaked Whale/Arnoux and Baird’s Beaked Whales (Berardius)

Where found: Arnoux’s beaked whale Berardius arnuxii lives in cold Southern Hemisphere waters and Baird’s beaked whale Berardius bairdii is found the cold temperate waters of the North Pacific.

Description: You would not be able to see the differences between Arnoux and Baird’s beaked whales except that they live on opposite ends of the world. They grow to 10–12 m in length and up to 14,000 kg (31,000 lb). They have very long prominent beak, even by beaked whale standards. The lower jaw is longer than the upper and the front teeth are visible even when the mouth is fully closed. The melon is particularly bulbous. The body shape is slender - the girth is only 50% of length. The body is uniformly coloured and a particular individual's colour may be anything from light grey through to black. The flippers are small, rounded and set towards the front of the body. The dorsal fin similarly is small and rounded and set about three-quarters of the way along the back. Adult males and females of both species pick up numerous white linear scars all over the body as they age and may be a rough indicator of age.

  • B. arnuxii is known as Arnoux's beaked whale, southern four-toothed whale, southern beaked whale, New Zealand beaked whale, southern giant bottlenose whale, and southern porpoise whale.
  • B. bairdii is known as Baird's beaked whale, northern giant bottlenose whale, North Pacific bottlenose whale, giant four-toothed whale, northern four-toothed whale, and North Pacific four-toothed whale.
Rendering of Giant Beaked Whale

Hyperoodon

Hyperoodon

Northern and Southern Bottlenose Whales (Hyperoodon)

Where found: Northern bottlenose whale are found in the North Atlantic Ocean and is found in cool and subarctic deep waters such as the Davis Strait, the Labrador Sea, the Greenland Sea and the Barents Sea and as far south as Cape Verde Islands. Southern bottlenose whales are probably the most abundant whale in Antarctic waters.

Description: These sister species are fairly rotund with an extremely bluff melon. The beak is long and white on males but grey on females. The dorsal fin is relatively small at 30–38 centimetres (12–15 in) and set behind the middle of the back. It is falcate (sickle-shaped) and usually pointed. The Northern species measures 9.8 metres (32 ft) in length when physically mature. The back is mid-to-dark grey, with a lighter underside. The Southern bottlenose whale smaller growing to 7.5 m (25 ft) in length when physically mature. The back is light-to-mid grey, also with a lighter underside. Males are about 25% larger than females. These bottlenose whales live up to 37 years. Weight estimates are hard to come by. For the northern bottlenose whale, 5,800–7,500 kilograms (12,800–16,500 lb) is given somewhat consistently, while the smaller and less studied southern species will be lighter. The bottlenose whales are some of the deepest diving mammals known, reaching depths of 1453 m (4767 ft) The whales feed on squid, sea cucumbers, herring, cuttlefish, sea stars and other benthic invertebrates.Video Northern Bottlenose Whale

Ziphius cavirostris

Ziphius cavirostris

Cuvier's beaked whale (Ziphius cavirostris)

Where found: Open ocean worldwide except in the Arctic and Southern oceans.

Description: The Cuvier's beaked whale or goose-beaked whale is the most widely distributed of all the beaked whales. Individuals commonly have white scars and patches caused by cookiecutter sharks. It prefers depth greater than 1,000 m (3,300 ft) and avoids ships, it is still one of the most frequently spotted beaked whales. The maximum known depth reached by the Cuvier's beaked whale is 2,992 metres (9,816 ft), or 1.8 miles, making it the deepest-diving mammal. The species name comes from Greek xiphos, "sword", and Latin cavus, "hollow" and rostrum, "beak", referring to the indentation on the head in front of the blowhole. The body of Cuvier's beaked whale is robust and cigar-shaped, similar to those of other beaked whales and can be difficult to distinguish from many of the mesoplodont whales at sea. Males and females are the same size up to about 5–7 m (16–23 ft) in length 2,500 kg (5,500 lb). The dorsal fin is curved, small and located two-thirds of the body length behind the head. Flippers are equally small and narrow and can be tucked into pockets in the body wall, presumably to prevent drag while swimming. Like other beaked whales, its flukes are large and lack the medial notch found in all other cetaceans. The head is short with a small, poorly defined rostrum and a gently sloping melon. A pair of throat grooves allow the whale to expand this region when sucking in its prey. Cuvier's beaked whale has a short beak in comparison with other species in its family, with a slightly bulbous melon. The melon is white or creamy in color and a white strip runs back to the dorsal fin about two-thirds of the way along the back. The rest of the body color varies by individual: some are dark grey; others a reddish-brown. The dorsal fin varies in shape from triangular to highly falcate, whilst the fluke is about one-quarter the body length. They live for forty years. Culvers beaked whale

Dolphins and porpoises are also classified as toothed whales, but since they appear as a separate group in this requirement, they are not listed here.


1b

Baleen Whales

1c

True Seals

1d

Eared Seals


Callorhinus ursinus

Callorhinus ursinus

Northern Fur Seal (Callorhinus ursinus)

Where found: The Northern Fur Seal is found in the north Pacific Ocean.

Description: The Northern Fur Seal, has substantial physical differences compared to other eared seals: its head is smaller, snout shorter and the hind flippers are proportionately largest of any eared seal. The most conspicuous physical feature of the fur seal is the fur itself; indeed, its genus name comes from the Greek for "beautiful hide". It consists of longer lighter guard hairs and a dense waterproof underfur of about 46,500 hairs per square centimeter.

Arctocephalus gazella

Arctocephalus gazella

Antarctic Fur Seal (Arctocephalus gazella)

Where found: As its name suggests, the Antarctic Fur Seal is distributed in Antarctic waters. Around 95% of the world population breeds at South Georgia.

Description: This fur seal has a short and broad snout compared with others in the family. Adult males are dark brown. Females and juveniles tend to be grey with a lighter underside. Antarctic Fur Seals appear to act alone when foraging and migrating. A strong male may have more than a dozen female partners in a single season. Territories are established on breeding grounds in October to early November, when the musty-smelling males are extremely aggressive in defense of their harems. Females gestate for just over a year - giving birth in November or December. Pups are weaned at about month old. Juveniles may then spend several years in the water before returning to begin their breeding cycle.

Eumetopias jubatus

Eumetopias jubatus

Steller Sea Lion (Eumetopias jubatus)

Where found: The Steller Sea Lion, also known as the Northern Sea Lion, lives in the temperate eastern Pacific.

Description: The Steller Sea Lion is the largest of the eared seals, measuring up to 3.3 m in length, with males weighing up to 1,100 kg while females weigh around 350 kg. Their coloration is lighter than in most sea lions, ranging from a pale yellow to a tawny and occasionally reddish, though they often appear darker in the water. The pups are born almost black and remain dark for several months.

Zalophus californianus

Zalophus californianus

California Sea Lion (Zalophus californianus)

Where found: The California Sea Lion is a coastal sea lion of the northern Pacific Ocean.

Description: The California Sea Lion has a streamlined body that contains a layer of blubber under the skin to provide warmth and buoyancy. Their large eyes help them adjust to low levels of light in underwater environments, while their whiskers augment their sense of touch. Their nostrils automatically close once they hit the water. Their long front flippers rotate outward for better movement on land, and propel them forward in water, where they are most at home.


1e

Dolphins/Porpoises

1f

Walruses (one kind)

1g

Sea Otter (one kind)

1h

Manatees


2

Know and locate the story of how God used a whale in Bible times.


This is, of course, the story of Jonah located in the Biblical Book of Jonah, .


3

What is the largest mammal in the sea?


The largest mammal in the sea, and indeed, the largest animal in the history of the world, is the Blue Whale (Balaenoptera musculus).


4

Explain the following words:


4a

Breaching


Breaching is when a whale leaps into the air and falls on their backs. There are a variety of explanations about why different whales and dolphins perform this artful leap. Some researchers have proposed it may be a behavior to dislodge parasites off of the whale's back, while others have interpreted it as a form of communication. Some believe the whale is just having fun!


4b

Echolocation


Echolocation is the biological sonar used by several mammals such as bats, dolphins and whales.

Animals that use echolocation emit calls out to the environment. They listen to the echoes that return from various objects in the environment. They use these echoes to locate, range and identify the objects. Echolocation is used for navigation and for foraging (or hunting) in various environments.

Toothed whales, including dolphins, porpoises, river dolphins, orcas and sperm whales, use echolocation because they live in an underwater habitat that has favorable acoustic characteristics and where vision is extremely limited in range due to absorption or turbidity.


4c

Spyhopping


Spyhopping is when a dolphin and whales are in a vertical stance so they can look at their surroundings above the water. The whale slowly rises straight out of the water, until its eye is above the water surface. After a few moments, the whale sinks back down. Again, we cannot be sure why whales spyhop, but they may be coming up to take a look around.


4d

Baleen


Baleen

Baleen makes up baleen plates, which are arranged in two parallel rows that look like combs of thick hair; they are attached to the upper jaws of baleen whales. Whales use these combs for filter feeding. Baleen whales scoop vast amounts of water into their mouths, and then push the water back out their mouths through the baleen plates. The baleen plates prevent fish and plankton from flowing out of their mouths. Whales are the only vertebrate group to use this method of feeding in great abundance (flamingos and crabeater seals use similar methods, but do not have baleen), and it has allowed them to grow to immense sizes.


4e

Pod


A pod is a social group of whales, porpoises, or dolphins.


4f

Harem


A harem is a group of female seals, which are corralled together by a male for the purpose of mating. The male Northern Fur Seals are possessive of individual females in their harem, often aggressively competing with neighboring males for females. Some males breed with up to 50 females in a single breeding season. Some types of whales also have harems.


4g

Plankton


Plankton are defined as any drifting organism that inhabits the water column of oceans, seas, and bodies of fresh water. They are widely considered to be one of the most important organisms on Earth, due to the food supply they provide to most aquatic life.



5

Draw a food chain of two different marine mammals.


phytoplankton → copepod → fish → squid → seal → orca

This "chain" can be described as follows: Orca (also known as "killer whales") feed upon seals, that feed upon squid, that eat small fish, that feed on copepods, that feed on microscopic algae.

phytoplankton → krill → baleen whales

Food loses efficiency as it travels up the food chain from prey to predator. This is because each creature in the chain uses some of the energy it gained from its food. By keeping their food chain short, baleen whales are able to efficiently consume enormous amounts of energy, and therefore, they are able to grow to enormous sizes.


6

What is the purpose of blubber?


Blubber is a thick layer of fat found under the skin of all cetaceans, pinnipeds and sirenians. It covers the whole body, except for the appendages, loosely attached to the muscles. It can comprise up to 50% of the body mass of some marine mammals during some points in their lives. Blubber serves several different functions, it is the primary area of fat on some mammals, and essential for storing energy. It is particularly important for species which feed and breed in different parts of the ocean. During these periods the species are operating on a fat-based metabolism.

Blubber also serves as an efficient thermal insulator, making it an essential for thermoregulation. It has advantages over fur (as used in Sea Otters) in this respect; fur can retain heat by holding pockets of air, but under pressure (while diving) the air pockets will be expelled. Blubber, however, does not compress under pressure. It can also aid in buoyancy, and acts to streamline the body.


7

Know two reasons that seals are hunted.


Seals are hunted for their fur, meat and oil. They are also hunted by fishermen to eliminate competition for fish. Seals sometimes take bites out of fish already caught in a fisherman's net, making the fish unfit for sale.


8

Describe why seals and dolphins can move so quickly in the water.


The seal's flippers are enormously long, and the skin between them forms a web which is used like a paddle to propel the seal along. They have long, sturdy claws on their front flippers which they use to help them move on land, especially when they need to grip onto rocks or ice


9

Do one of the following:


9a

Take a trip to an aquarium. Learn about and observe the daily feeding schedule of a marine mammal.


This option will almost certainly be the most rewarding for your Pathfinders, but it will also require the most work on your part to get it organized. Try to contact the aquarium before setting off on your trip so that you can make arrangements to meet with a staff member there. They are usually very willing to help you, and will be delighted to provide you with information regarding the daily feeding schedule. Note that some zoos have aquariums too, so if a zoo is more convenient than an aquarium, you might want to investigate this possibility.

If you are planning to visit a zoo or aquarium, be aware that there are various honors that have requirements which can be met by visiting a zoo or aquarium. Individuals can work on multiple honors in one visit, or parts of your group may work on different honors during the same visit.

Here is a list of honors which have requirements that can be met by visiting a zoo or aquarium:

Animal Camouflage

Bogs & Fens

Creation

Creationism

Dunes

Endangered Species

Harmful Animals

Island Fishing

Marsupials

Migration

Oceans

Palouse

Rainforests

Raptors

Sharks

Taiga

Temperate Deciduous Forests

Temperate Grasslands

Venomous Animals



9b

Write a 500-word report on a marine mammal. Include pictures.


Much of the material for the answers presented here was taken from Wikipedia. You can start your research by reading the full articles:


9c

Write a 500-word report on current events involving marine mammals and their environment and how they could be endangered.


Search Google News for marine mammals to find out about current events. http://news.google.com/news?hl=en&ned=us&q=marine+mammal&btnG=Search+News You can also search http://news.google.com for a particular marine mammal (such as whales, seals, dolphins, or manatees).

Note

This Honor and the Cetaceans Honor have considerable overlap. Consider working on them together.




References

Much of the material here as adapted from numerous Wikipedia articles.