Sperm whale: who he is and how he lives


SPERM WHALE

SCIENTIFIC CLASSIFICATION

Kingdom

:

Animalia

Phylum

:

Chordata

Subphylum

:

Vertebrata

Class

:

Mammalia

Order

:

Cetacea

Suborder

:

Odontoceti

Family

:

Physeteridae

Kind

:

Physeter

Species

:

Physeter macrocephalus

Common name

: sperm whale

GENERAL DATA

  • Body length: female 11 m; male 15 - 18 m
  • Weightfemale 13-14 t; male 35-45 t
  • Lifespan: 70 years
  • Sexual maturity: female 7-13 years of age (8-9 meters in length); male: 10 years or older (10-12m long)

HABITAT AND GEOGRAPHICAL DISTRIBUTION

The sperm whale, Physeter macrocephalus of the family Physeteridae it belongs to the order of the odontocetes, that is to say of the cetaceans with teeth (such as leorcas), contrary to when it happens for example in the blue whale in the humpback whale which instead belong to the order of the mysticetes.

It is the largest odontoceta cetacean that exists on earth and is found in all the seas and oceans of the world. We can say that its habitat is the open sea, that is to say all the waters where the depths reach and exceed 1000 m of depth and that are not covered by ice: from the equator to the higher latitudes even if it has been observed that it is present more frequently in the continental slope (the steep step that exists between the continental shelf and the deep sea) or in deeper waters. It is also found in closed seas such as the Mediterranean Sea, the Sea of ​​Okhotsk, the Gulf of California and the Gulf of Mexico. It seems that only males, alone or in groups, go to higher latitudes while females and juveniles remain in the warmer waters of tropical and subtropical zones all year round (waters with temperatures around or above 15 ° C) at latitudes. less than 40 °.

CHARACTER, BEHAVIOR AND SOCIAL LIFE

They are animals that live in even large groups formed mostly by females with their young.

The groups can reach up to 50 units but generally they are formed by no more than 12 individuals. Generally the adult males move either in groups of only males or, less frequently, alone, joining the females only for short periods, to mate .

PHYSICAL CHARACTERISTICS

The first peculiarity of the sperm whale is the great sexual dimorphism as the adult male is about 3 times higher than the adult female both in length and weight.

Compared to other cetaceans, the sperm whale is easily recognizable as it is characterized by a square head, 1/3 the length of the body.

There is a single S-shaped breather and is located in the front of the head, towards the left.

The skin appears wrinkled and wrinkled and is gray or black, variously streaked with a lighter shade; around the mouth, especially near the corners, it is light in color. The ventral part of the body may also be lighter in color.

The sperm whale has practically no dorsal fin as it is small, large and short. The pectoral fins are at most 2 m long and 1 m wide; the caudal fin is up to 4 m wide and allows the sperm whale to reach a speed of up to 20 km / h even though it normally travels at 5-10 km / h.

It has a relatively small and thin mobile jaw with 18-25 teeth on each side 3 to 8 cm long, while in the jaw they are smaller and able to fit the teeth placed in the jaw.

A peculiarity that exists only in the sperm whale is the presence of a organ of the spermaceti (in the skull in a kind of depression) which in its lower part is formed by a fibrous and elastic mass rich in oil surmounted by another tank full of the real spermaceti which is nothing more than an oily substance (in equal quantities from 1 to 5 t for individuals) colorless and transparent.

What exactly this organ is used for is not known; it is hypothesized that it plays an important role in the hydrostatics of the sperm whale or in the opening and closing of the vent during diving or in the echolocation system.

Another unique feature of the sperm whale is the so-called ambergris, substance that is produced in the intestine appears to be from the remains of ingested cephalopods. Up to 60 kg can be found per sperm whale. When fresh it has an intense and unpleasant aroma but when exposed to air it has a sweet and musky aroma. Due to these characteristics it is highly sought after in perfumery and given the scarcity of its resources it has a very high value.

Sperm whales are among the cetaceans that more than any other go deep, up to 1000 m having a lung capacity that allows them to remain submerged for up to an hour (the average is 20-50 minutes at a depth of 300- 600 m). Once they emerge from this long dive they must stay on the surface for at least 12-15 minutes, breathing regularly to restore oxygen reserves. It goes without saying that when the sunlight does not reach these depths, there is absolute darkness and sperm whales exploit their echolocation abilities to see.

COMMUNICATION

The sperm whale communicates with its peers (intraspecific communication) through the emission of very particular sounds that resemble more a morse code than a real sound modulation, as happens for example in humpback whales and it would seem that every animal has a its particular frequency that would allow each individual to be recognized. These sounds are audible at least 10 km away from the place of emission and this would allow the different groups to keep in contact with each other.

EATING HABITS

The main food source of the sperm whale are squid and in particular the giant squid which it searches in deep waters (even 1000 m) but also feeds on rays, octopuses and fish.

On average, an adult sperm whale consumes around 900 kg of food per day.

In consideration of the fact that the sperm whale generally hunts at great depths, in order to locate the prey it uses echolocation, a system similar to sonar, which produces sounds that strike the prey and return back, making the sperm whale understand what it is in front of him. Some scholars speculate (but it has not been proven) that sperm whales emit sounds of such intensity that they stun fish and molluscs in order to facilitate their subsequent capture.

REPRODUCTION AND GROWTH OF THE SMALL

The females become sexually mature when they reach 8-9 m in length which corresponds approximately to 7-13 years of age while the males when they reach a length of 10-12 m which corresponds approximately to 10-12 years of age. age.

Males do not appear to have an effective role in rearing and caring for the young.

The gestation lasts about 14-16 months at the end of which only one puppy is born weighing about 1 ton and is 3 to 5 m long. The young remain with their mother until they reach two years of age.

PREDATION

If we exclude the man, there are no natural predators for the sperm whale. Only killer whales can attack the young if they can isolate them from the group and the mother.

STATE OF THE POPULATION

The sperm whale is classified on the IUNC Red list among animals vulnerable to extinction in the wild: VULNERABLE (VU).

Now, in the past, sperm whales have been subjected to a very ruthless hunt: during the nineteenth century they were hunted for spermaceti (used as a lubricant), for ambergris (used in perfumery) and for oil, fat and meat in general. Starting from the early 1900s his hunting became even more intense thanks to the Norwegian, Sven Foyn who in 1868 invented the harpoon cannon which, associated with steam boats, had facilitated the hunting of these cetaceans. 1950 was a particularly intense year, so much so that 25,000 kills were recorded in a single hunting season.

Only in 1966 did the IWC (International Whaling Commission) begin to protect whales and only in 1986 did it set commercial catch limits to zero even though Iceland, Norway and the Russian Federation did not join and continue to hunt for whales. these animals and Japan continues hunting for scientific research purposes.

Today the causes that endanger the life of these cetaceans are different: the catches made for the purpose of scientific research; catches made incidentally with fishing nets; the hostility of fishermen as many of these cetaceans steal fish from their nets; noise pollution that appears to disturb sperm whales; collisions with ships especially in the Mediterranean and the Canary Islands.

Another important aspect that is often overlooked is that when a specimen, male or female, dies, being social animals, the balance of the group where the animal lived is broken, with serious consequences on its cohesion and stability.

The Physeter macrocephalus species is listed in Appendix I of CITES (Convention on International Trade in Endangered Species of Fauna and Flora, known as the "Washington Convention" which includes endangered species and trade is permitted only in exceptional cases) and in Appendix I of the CMS (Convention on the Conservation of Migratory Species of Wild Fauna, known as the "Bonn Convention", which reports migratory species that have been classified as endangered in whole or in a significant part of their area and in respect of which individual states must adopt adequate measures for the protection and conservation or restoration of the habitats in which they live, also mitigating the obstacles to their migration).

One aspect that bodes well for the survival of this species is that their main source of food, deep-sea squid, are not threatened by either human fishing or pollution, as they live in such deep waters that both fishing and fishing. pollution for the moment cannot reach them.

CURIOSITY'

In English the sperm whale is known as sperm whale to remember the substance produced by the organ of the spermaceti so called because it was originally thought to be sperm.

The name "sperm whale" means "head of oil" due to the organ of the sparceti.

The sperm whale was the protagonist of one of the greatest novels in world fiction, written in 1851 by Herman Melville entitled Moby Dick, the white whale. The story is told by Ishmael, a young sailor who embarks on the whaler Pequod to travel around the world. The ship is commanded by the Captain Ahab who is haunted by an obsession: to take revenge on Moby Dick, a white whale who a few years earlier had devoured his leg, leaving him numerous wounds in his body and soul that had led him almost to madness and to a hatred so great and deep he had also involved his crew. After various adventures Ahab manages to find the white whale and embarks on an epic fight with her that will lead to the death of Captain Ahab, of all his crew (except Ishmael) and to the destruction of the ship.

Several films have been made of this story: in 1926 for Warner Bros with the direction of Millard Webb and in 1930 with that of Lloyd Bacon but the 1956 version directed by John Huston which saw Gregory Peck as actors in the role of captain. Ahab is the one who was most famous (we report to follow the final sequences of the film).


Video: Sperm Whale Communication: What we know so far. Understanding Whale Communication: First steps


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