VOICES OF THE SEA
Chapter Three
SPERM WHALE Physeter macrocephalus
Sperm whales are easily recognized by their massive heads and prominent rounded foreheads. The mighty sperm whale is a multiple record-breaker. It is the largest of the toothed whales with some males reaching 20 metres in length. Its enormous box-like head with left-sided blow hole contains the biggest brain of any living animal known to have lived on Earth. It is also the deepest diving mammal, reaching depths of 3,000 metres (nearly two miles) although the average dive is between 300 and 600 metres. These dives can last for a couple of hours due to the oxygen stored in their muscles before the whale has to come up for breath. Their heads also hold large quantities of a substance called spermaceti. Whalers once believed that the oily fluid was sperm, but scientists still do not understand the function of spermaceti. One common theory is that the fluid—which hardens to wax when cold—helps the whale alter its buoyancy so it can dive deep and rise again. Until recently, no-one knew how sperm whales hunt in the abyss, scientists now have a theory. The reason sperm whales dive so deep is that there’s lots of food down there including giant squid which is over 30 feet long. A mile down, there’s no light. The whale must find its prey through echolocation interpreting the echoes of the clicks it makes. But these are no ordinary clicks. These hunting clicks are the loudest sounds made by any living thing, louder than a thunderclap. Produced in its fiveton nose, the whale’s clicks travel backwards, then are reflected forwards through a series of oil-filled lenses which focus them into a narrow sound beam, like a sonic laser. These toothed whales eat thousands of pounds of fish and squid—about one ton (907 kg) per day.
05
VOICES OF THE SEA
SPERM
12
Sperm whales hunting clicks are the loudest sounds made by any living animal on Earth
Sperm whales are often spotted in groups (called pods) of some 15 to 20 animals. Pods include females and their young, while males may roam solo or move from group to group. Females and calves remain in tropical or subtropical waters all year long, and apparently practice communal childcare. Males migrate to higher latitudes, alone or in groups, and head back towards the equator to breed. Driven by their tale fluke, approximately 16 feet (5 meters) from tip to tip, they can cruise the oceans at around 23 miles (37 kilometers) per hour.
Length - 20 m Wieght - 60 Tons (Max.) Type - Toothed LIfe span - 50~70 years Food - Squid
SPERM
12
Sperm whales sleep in short bursts usually in a vertical position
12
VOICES OF THE SEA
These popular leviathans are vocal and emit a series of “clangs” that may be used for communication or for echolocation. Animals that use echolocation emit sounds that travel underwater until they encounter objects, then bounce back to their senders—revealing the location, size, and shape of their target. Sperm whales were mainstays of whaling’s 18th and 19th century heyday. A mythical albino sperm whale was immortalized in Herman Melville’s Moby Dick, though Ahab’s nemesis was apparently based on a real animal whalers called Mocha Dick. The animals were targeted for oil and ambergris, a substance that forms around squid beaks in a whale’s stomach. Ambergris was (and remains) a very valuable substance once used in perfumes. Despite large population drops due to whaling, sperm whales are still fairly numerous.
SPERM
12
Sea Level
124M Free diving record with fins
DEEP SEA HUNTING Sperm whales dive deep and use their hunting clicks to locate their prey.
330M
500 m
Scuba record
1000 m
1000M Deepest light can penetrate
The hunting clicks are produced at the front of the whales 5 tonne nose. They then travel backwards through the spermaceti and are reflected forwards through a series of oil filled lenses called junk chambers which focuses them into a narrow sound beam, like a sonic laser. 2000 m
3000M Maximum depth Sperm whales dive to hunt
Chainsaw 3000 m
100dB
Inside Sperm Whale Head
Clicks reflected
Spermaceti Blow hole
Clicks produced in the distal sack
Skull
Eye
Junk Chamber
Sperm whales make the loudest sound of any living animal. Their hunting clicks reach 230 dB (Decibels). In the air it would still reach a staggering 170 dB
Jet
Shotgun Blast
130dB 140dB Pain thresh hold for humans (125dB)
Sperm whale
170dB
BOTO RIVER DOLPHIN Inia geoffrensis
Botos live exclusively in the the South America in the Amazon and Orinoco river basins. They have a ridge along their back rather than a dorsal fin and its fat, heavy body is surprisingly flexible. Paddle-like flippers which move in a circular motion provide exceptional manoeuvrability, making up for a lack of speed. Even swimming backwards on some occassions! The Amazon & Orinoco river basins provide all the food in its highly diverse diet, including at least 40 different species of fish. The Botos use two completely separate sound systems. Communication clicks and busses and their echolocation clicks and busses. The Boto’s clicks and buzzes are focused into a sound beam by its bulging forehead melon. The beam works like a sonic head-torch allowing the dolphin to build up a clear picture of its surroundings in the murky water.
11
VOICES OF THE SEA
Length - 2.5 m Wieght - 185 Kg Type - Porpoises LIfe span - 15~20 years Food - Small fish & crabs
BOTO
12
The Botos need all their manoeuvrability and all the sonar skills they possess to operate in the sort of underwater environment that the Amazon provides. It’s as tangled and spiny underwater as it is on the surface and the water is very cloudy and dark like a well brewed tea. While all dolphins can echolocate, Botos’ clicks have a higher frequency and better resolution than any other dolphin, allowing them to distinguish objects as small as a pin. Even in zero visibility, catching fish is child’s play.
13
VOICES OF THE SEA
BOTO
12
12
VOICES OF THE SEA
Boto’s echolocation is so accurate they can distinguish objects as tiny as a pin
NARWHAL
Monodon monoceros
The narwhal is the unicorn of the sea, a pale-colored porpoise found in Arctic coastal waters and rivers. These legendary animals have two teeth. In males, the more prominent tooth grows into a swordlike, spiral tusk up to 8.8 feet (2.7 meters) long. The ivory tusk tooth grows right through the narwhal’s upper lip. Scientists are not certain of the tusk’s purpose, but some believe it is prominent in mating rituals, perhaps used to impress females or to battle rival suitors. Females sometimes grow a small tusk of their own, but it does not become as prominent as the male’s. Narwhals are related to bottlenose dolphins, belugas, harbor porpoises, and orcas. Like some other porpoises, they travel in groups and feed on fish, shrimp, squid, and other aquatic fare. They are often sighted swimming in groups of 15 to 20, but gatherings of hundreds—or even several thousand—narwhals have been reported. Sometimes these groups become trapped by shifting pack ice and fall victim to Inuit hunters, polar bears, or walruses.
17
VOICES OF THE SEA
NARWHAL
12
12
VOICES OF THE SEA
The charismatic narwhal is the legendary ‘unicorn of the sea’. It’s also thought that narwhal horns used in trade or washed up on beaches gave credence to the myth of unicorns on land. The horn is more properly called a tusk. Narwhals only have two teeth and in the males, the left one grows out of the jaw into a long spiralled tusk that can reach 2.5m in length and is prone to breaking. Suggested uses for such an impressive appendage include to spear food, for defence and as a weapon for competing males. However, its most likely use is to impress females, as an indication of the fittest mate. Narwhals are inhabitants of Arctic waters and are found at all depths. They tend to stay close to loose pack ice, where breathing holes are maintained through the sheets of ice. The narwhal is the unicorn of the sea, a pale-colored porpoise found in Arctic coastal waters and rivers. These legendary animals have two teeth. In males, the more prominent tooth grows into a swordlike, spiral tusk up to 8.8 feet (2.7 meters) long. The ivory tusk tooth grows right through the narwhal’s upper lip. Scientists are not certain of the tusk’s purpose, but some believe it is prominent in mating rituals, perhaps used to impress females or to battle rival suitors. Females sometimes grow a small tusk of their own, but it does not become as prominent as the male’s.
Length - 4 m Wieght - 500 Kg Type - vvLIfe span 45~50 years Food - Small fish
NARWHAL
12
KILLER WHALE Orcinus orca
12
VOICES OF THE SEA
Killer whales are actually the largest species of dolphin. Their dorsal fin can be used to recognise individuals, and in males can measure an incredible 1.8 metres in height. Killer whales are found in every ocean on the planet, and as well as being the most widely distributed, they also hold the title for fastest sea mammal, reaching speeds of up to 55kph. A distinguished marine predator, these strikingly marked killers have even been known to hunt down grey and blue whales. Killer whales are found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas.
Length - 9 m Wieght - 9 tonnes Type - Porpoises LIfe span - 50-80 years Food - Fish, seals, walruses and other whales
KILLER
12
Killer whales as a species have a diverse diet, although individual populations often specialize in particular types of prey. Some feed exclusively on fish, while others hunt marine mammals such as sea lions, seals, walruses and even large whales. Killer whales are regarded as apex predators, lacking natural predators. Killer whales are highly social; some populations are composed of matrilineal family groups which are the most stable of any animal species. Their sophisticated hunting techniques and vocal behaviors, which are often specific to a particular group and passed across generations, have been described as manifestations of culture.
KILLER
12
Killer Whales use herding calls to bunch fish together making them easier to catch
KILLER
12